21 Carboxylic Acid Derivatives

Draw the structures of glucose, its anomers, and its epimers, both as Fischer projections and chair conformations.

Draw their structures from their names.

Predict the reactions of carbohydrates with acidic and basic solutions.

Predict the reactions that convert their carbonyl groups to acetals.

Biochemists have found that cells in organisms recognize other cells by the pattern of sugars on their surfaces.

White blood cells can identify foreign cells as pathogens if the polysaccharide sequence on the foreign cell surface does not match the usual sequence.
Red blood cells have patterns of sugar that identify them as different types of blood.
Blood cells with d-galactose at the end of the sequence.
Both types of blood cells have the same sequence.

Carbohydrates are the most abundant organic compounds.

Plants and animals use carbohydrates to store energy and deliver it to their cells.

Most living organisms use water and carbon dioxide as oxidizers.

The plants can get the units from the starch.
The storage unit for solar energy is called the starch.

Carbohydrates are in one form or another in almost every aspect of human life.

Like other animals, we use the energy in our food to produce and store energy in our cells.

In cells, they form links to lipids to make glycoproteins, which serve important functions in the immune system, hormones, and cell membranes.
Cotton and linen are used to make clothing.
We use wood to build houses and as a fuel to heat them.
The page is made from fibers.

Carbohydrate chemistry is one of the more interesting areas of chemistry.

Many chemists are employed by companies that make food, building materials, and consumer products.

All biologists need to understand the roles of Carbohydrates in the plant and animal kingdoms.
The structures and reactions of carbohydrates may seem complicated at first glance.
We can study the simplest organic compounds as easily as we study the more complex structures and reactions.

Sugars have a sweet taste.

C(H2O) is the empirical formula of most simple sugars.

These compounds are called "hydrates of carbon" or "carbohydrates" because of their formulas.

Both sugars are polyhydroxyaldehydes and are projected toward the viewer and ketone.

H OH is the abbreviation for H C* OH.

The IUPAC name is always at the top of the projection.

The second carbon from the top is usually the Fischer projection carbonyl group.

There are mirror images of arabinose and erythrose.

Monosaccharides are O and fructose.

Carbohydrate structures can be drawn using projections.

The disaccharide in table sugar can be used to make two different types of sugar.

The characteristic sweet taste we associate with sugars can be found in both monosaccharides and disaccharides.

There are biopolymers of glucose in them.

Thelysis of either of the two sugars gives the molecule of glucose.

The simplest monosaccharides are examples of how to understand the chemistry of these more complex carbohydrates.

We will apply these principles to more complex disaccharides.
Predicting the chemistry of biomolecules can be done by applying the chemistry of simple organic molecules with similar functional groups.

Most sugars have their own common names.

There are simple ways to remember the structures of these names.
The study of monosaccharides can be simplified by grouping similar structures together.

The first two criteria are reflected in the terms describing monosaccharides.

It is an aldohexose when it has an aldehyde and six carbon atoms.
Fructose has six carbon atoms, but it is also called a ketone.
The ketone on C2 is the second carbon atom of the chain.
The most common monosaccharides are aldohexoses and aldopentoses.

There are two enantiomers of glyceraldehyde.

The structures of natural and synthetic sugars were determined in the 19th century.

They found a way to make larger sugars out of smaller ones by adding a carbon atom.

A tetrose could be converted to a triose by a degradation.

There is only one aldotriose.

The dextrorotatory (+) enantiomer of glyceraldehyde was always given by degradation to the naturally occurring sugars.

Synthetic sugars degraded to the levorotatory enantiomer of glyceraldehyde.
The d and l relative configurations were used to distinguish the naturally occurring d sugars from the unnatural l sugars.

We know the absolute configurations of glyceraldehyde.

The configurational standards for monosaccharides are served by these structures.

Alteration to glyceraldehyde.

A smaller sugar is created by removing the aldehyde carbon atom from an aldose.
The triose is degraded by the sugars of the d series.
The OH group of the d sugars must be on the right in the projection.

The d or l configuration is determined by the bottom asymmetric carbon and the enantiomer of a d sugar.

Most naturally occurring sugars have the d configuration, and most members of the d family of aldoses are found in nature.

The d or l configuration doesn't tell us which way a sugar rotates.
This must be determined in an experiment.
Some sugars have different rotations.

Four aldopentoses and eight aldohexoses are given by adding another carbon to these aldotetroses.

In Section 23-11, we describe the Kiliani-Fischer synthesis, which adds a carbon atom and creates pairs of sugars just like we have drawn them in this family tree.

The d and l system of relative configurations could not be used to determine the absolute configurations of compounds.

All of the sugars are naturally occurring except for threose, lyxose, and allose.

It was not necessary to revise all the old structures after this guess proved to be correct.

The relative should be based on the structures of erythrose configuration and the sign of rotation.

The number of a carbon atom is assumed to be C2.

The C2 epimer of erythrose is threose.

The sugars differ by the stereochemistry of a single asymmetric carbon atom.

The number of the carbon atom is assumed to be C2.

The C4 is the Epimer of d-xylose.

This "epimer" is actually an l-series sugar, and we have seen its enantiomer.
The name for this sugar should be correct.

Cyclic acetals or hemiacetals are the most common types of carbohydrates.

These groups are stable because of their shapes and sizes.

In Chapter 18 we saw that an aldehyde reacts with one molecule of alcohol to give a hemiacetal, and with a second molecule of alcohol to give an acetal.

The hemiacetal is not as stable as the acetal.
Hemiacetals are rarely isolated.

The OH group is a nucleophile.

A hemiacetal is given by deprotonation.

The aldehyde group and the hydroxy group are part of the same molecule.

If they result in five or six rings, cyclic hemiacetals are very stable.
Five- and six-membered hemiacetals are more stable than their open-chain forms.

Aldoses have sev eral hydroxy groups.

The solid form of an aldose is called a hemiacetal.
The equilibrium favors the hemiacetal for most sugars.

There are either five membered or six membered rings in hemiacetals.

The equilibrium favors six-membered rings with a linkage between the aldehyde carbon and the hydroxy group.

There is a new asymmetric carbon atom in the hemiacetal.

Section 23-5 talks about the stereochemistry at C1.

The Haworth projection is used in biology texts, but most chemists prefer the more realistic chair conformation.

The projection is on the right side.

The groups that were on the right in the projection are down in the structure, while the groups that were on the left are up.

C5 and C6 are away from you.

The C5 hydroxy group can form a part of the ring if the bond is rotated.

O bond to 2 oxygens.

The form of Glucose is similar to that of the hemiacetal form.

Draw the result when the ring is closed.

The oxygen is at the back, right-hand corner, and C1 is at the far right.
It is easy to identify C1 because it is the only carbon bond to two oxygens.
Section 23-5 talks about the hydroxy group on C1 being either up or down.

There are differences between the sugar in question and theglucose.

The following procedure can be used to draw d-hexoses.

The hemiacetal carbon is drawn at the far right and the ring oxygen is at the back right corner.

There are substituents on both sides of the ring.

Put all the ring substituents in the middle of the chair.

If you notice how other sugars differ fromglucose, you can make the appropriate changes.

In Draw the cyclic hemiacetal forms of d-mannose and d-galactose, both as chair conforma the Fischer projection and in the tions, you can learn to draw.

All substituents are the C4 epimer of glucose.

The chair conformations are easier to draw, so we will do them first.

The structure of the carbon atoms needs to be numbered.

The substituent on C2 is Mannose, which is the C2 epimer.

Galactose is the C4 epimer of C2 mannose, C3 allose, and C4glucose.

Let's take a look at the projection for galactose.

The groups on the right should follow along with your models.

The projection should be left and right.

Draw the final hemiacetal after closing the ring.

Section 23-5 talks about the hydroxy group on C1 being either up or down.
A wavy line is a sign of ambiguous stereochemistry.

Lay down the Fischer projection and draw the Haworth projection for the structure of d-mannose.

The C3 epimer is called Allose.

The form of d-allose should be drawn first in the chair and then in the projection.

Some sugars are not six-membered rings.

Five-membered rings are formed by many aldopentoses.
Five-membered rings are usually depicted as flat projections because they are not puckered as much.

A five-membered hemiketal is formed by Fructose.

Flat Haworth structures are usually represented as five-membered rings.

Carbohydrates and Nucleic Acids are drawn with the ring oxygen in back and the hemiacetal carbon on the right.

There is a CH2OH at the back left.

The Cyclic structures of monosaccharides are named after their rings.

The ring is in the sugar.

The C4 Epimer is called Talose.

The degradation of d-glucose gives d-arabinose.

Arabinose is the most stable form.

Ribose is most stable in its furanose form.

The carbonyl group in d-galactose can be isomerized from C1 to C2 with brief treatment.

The product is called the C4 epimer.
Draw the structure of the product.

The flat carbonyl group is converted to an asymmetric carbon when a pyranose or furanose ring closes.

The group can either be directed up or down.

The figure shows the anomers.

The anomeric carbon has a hydroxy group that is down in the anomer and up in the b anomer.

All of the substituents of the b anomer are in the equator.

The OH group is called the anomeric hydroxy group.

The b anomer is called the OH group up.
We can draw the a and b anomers of most aldohexoses by remembering that the b form has all of its substituents in the equator.

The a anomer has the CH2OH group in it.

This rule works for all sugars, from the d and l series to furanoses.

The following monosaccharides can be drawn using chair conformations for the pyranoses and Haworth projections for the furanoses.

omers have different properties because they are diastereomers.

b-d-glucopyranose has a melting point of 150 degC, while a-d-glucopyranose has a melting point of 146 degC.
There is a pure form of a-d-glucopyranose whenglucose iscrystallised from water.
Pure b-d-glucopyranose can be formed if the water is allowed to evaporate at a temperature of 98 degC.

The two anomers are in equilibrium through a small amount of the open-chain form, and this equilibrium continues to supply more of the anomer that is crystallizing out of solution.

An interesting change in the specific rotation is observed when one of the pure glucose anomers is dissolved in water.

The anomer's specific rotation gradually decreases from an initial value of +12deg to +62deg.
The rotation of the b ano mer increases when it is dissolved.

The two anomers convert in solution.

The b anomer is given by crystallization below 98 degC.

The value for the equilibrium mixture of anomers is listed in the specific rotation of glucose.

It is reasonable that the more stable b anomer should take the lead when we remember that the anomeric hydroxy group is in the a anomer and the b anomer.

galactose muta rotates when it is in water.

The b anomer has a specific rotation of +52.8deg.
The rotation of the pure anomers gradually changes when they are dissolved in water.

Determine the percentages of the two anomers.

A nickel catalyst is the most common reagent.

A new asymmetric carbon atom is created by the reduction of a ketose.

Food Additives and Sugar Substitutes are some of the uses of sugar alcohols.

Sorbitol is made by hydrogenation.
Mannitol can be made from seaweed or mannose.

A new asymmetric carbon atom can be created by reduction of fructose.

The products are made from mannitol and glucitol.

When d-glucose is reduced, it results in active glucitol.

The product is not active when the d-galactose is reduced.

l-gulose is an aldohexose that reduces to give d-glucitol.

A variety of reagents oxidize monosaccharides.

Oxidation is used to identify the functional groups of a sugar, to help to determine its stereochemistry, and as part of a synthesis to convert one sugar into another.

The aldehyde group of an aldose is oxidized by bromide water.

The alcohol groups don't oxidize with bromide water, which is why it is used for this oxidation.
The carbonyl group is not affected by bromine water's acidic nature.
Because bromine water oxidizes aldoses, it serves as a useful test to distinguish between them.
bromine water oxidizes gluconic acid.

The oxidizers are nitric acid and glucaric acid.

An aldose has an aldehyde group which reacts with Tollens reagent to give an aldonic acid and a silver mirror.

This oxidation is not a good synthesis of the aldonic acid because Tollens reagent is basic and promotes rearrangements.

Tollens test can't distinguish between aldoses and ketoses because the basic Tollens reagent promotes rearrangements via an enediol form.

Diabetes leads to fast isomerizations and must be monitored.

The enolate ion is no longer asymmetric when the group is reversibly removed.

A mechanism for the base-catalyzed equilibration of glucose to a mixture of chamber is proposed.

The isomerization of a ketose to an aldose can be done via the enediol intermediate.

Two different enolate ion are created by removing one or the other protons.

The Tollens reagent must react with the open-chain form of the sugar to be effective.

The sugar does not react with Tollens reagent if the cyclic form cannot open.
The acetal is stable under neutral or basic conditions.
The sugar gives a negative Tollens test if the carbonyl group is in the form of a cyclic acetal.

Because they are stable acetals, they cannot open their open-chain forms.

They are locked in a form.

The Tollens test distinguishes between sugars that are reduced and sugars that are not.

Nonreducing sugars are acetals.

It's called D-fructofuranoside.

ribose is the C2 epimer of arabinose.

An alcohol and a trace of acid catalyst are used to convert aldehydes and ketones to acetals.

The acetals we call glycosides are also converted by these conditions.
Both anomers of the glycoside are formed under these acidic conditions, regardless of the anomer used as the starting material.
The mixture of methyl glucosides is created by the acid-catalyzed reaction of glucose with methanol.

Like other acetals, glycosides are stable to basic conditions, but they hydrolyze in a free sugar and alcohol.

Glycosides are stable with basic reagents and basic solutions.

Methanol is aglycone in a conjugate.

Some aglycones are bonded through an oxygen atom, while others are bonded through a nitrogen atom or some other Heteroatom.

Disaccharides and Polysaccharides will be considered in Sections 23-12 and 23-13.

An aglycone is a group of carbons.

A true acetal is an oxygen atom and a nitrogen atom.

The second part of the mechanism for acetal formation is the same as the first part.

There is a mechanism for the formation of b-d-glucopyranoside.

The mixture of the a and b anomers of ethyl-d-fructofuranoside may be caused by the glycosylation of the proteins.

Draw the beginning of diabetes.

Sugars are insoluble in organic solvents because they contain several hydroxy groups.

Sugars form syrups like honey and molasses because they are difficult to recrystallize from water.
sugars behave like simpler organic compounds if they are alkylated to form ethers.
The ethers are easy to purify by recrystallization and simple chromatographic methods.

The totally methylated ether is given by the treatment of an aldose or a ketose.

Stereochemistry at the anomeric carbon is usually preserved if the conditions are carefully controlled.

The OH group gives the ether.

The configuration at the anomeric carbon is not broken.

The most common method for forming simple ethers is the Williamson ether synthesis.

A simple sugar would isomerize.
If the sugar is first converted to a glycoside by treatment with an alcohol and acid catalyst, a modified Williamson method may be used.
The acetal is stable to base.
The methylated carbohydrate is given by the treatment of a glycoside with sodium hydroxide and dimethyl sulfate.

The ring sizes of sugars can be determined with the help of methylation and hydrolysis.

The five groups are not the same.
There are four different types of ethers, one of which is the glycosidic methyl group of an acetal.

ethers are stable under these con ditions.

Acid hydrolyzes only the acetal methyl group when it is treated.
The six-membered ring of a pyranose can be seen in the cyclic form of b-d-glucose.

When fructose is treated with an excess of silver oxide, show the product that results.

Show what happens when the product of part a is used.

Hydroxy groups can be converted to silyl ethers.

The conversion of sugars to their silyl ethers can be done with the use of chlorotrimethylsilane and tertiary amine.

Sugars are usually converted to silyl ethers to make them more volatile and easier to handle.

It would be more likely for glucose to char and decay inside the gas chromatograph than it would be to flow through the column with the gas phase.
The trimethylsilyl is more volatile and can survive gas chromatography and mass spectrometry at a low temperature.

Watersoluble, not volatile organic-soluble, volatile Oxidation of glucose at C6 produces glucuronic acid.

NaOH and dimethyl sulfate were used to make the glucuronide derivative a-d-glucopyranoside.

To form esters, acylate the hydroxy groups.

Sugar esters can be easily dissolved in common organic solvents.
The hemiacetal on the anomeric carbon is acetylated by this reaction.

All the hydroxy groups of a sugar are converted to acetate esters with the help of acetic anhydride and pyridine.

The stereochemistry at the anomeric carbon is usually preserved.

The product is the same as the anomer of the acetate if we start with a pure b anomer.

Predict the products formed when sugars react with acetic anhydride and pyridine.

The method for shortening the chain of an aldose was briefly mentioned in our discussion of d and l sugars.

The bromine-water oxidation of the aldose to its aldonic acid is the first step of the degradation process.

The oxidizer of the carboxyl group to CO2 is hydrogen peroxide and the oxidizer of the carbon atom is ferric sulfate.
The degradation is used for structure determination.

The structure of d-lyxose should be given.

D-threose comes from degradation of d-lyxose.
The structure of d-threose should be given.

D-allose and d-allose degradation give the same aldopentose.

The structure of d-altrose should be given.

A chain-lengthened sugar with a new carbon atom at C1 and the former aldehyde group now at C2 is the result of this process.

For determining the structure of existing sugars and for synthesizing new sugars, this synthesis is useful.

The asymmetric aldehyde carbon atom is the first step in the formation of the cyanohydrin.

D-arabinose reacts with HCN to give the following cyanohydrins.

The hydrogenation of these cyanohydrins gives two imines.

The hydrogenation is done using a poisoned catalyst of palladium on barium sulfate.

The synthesis accomplishes the opposite of the degradation.

The Kiliani-Fischer synthesis converts the shortened aldose back into a mixture of the same two C2 epimers.

Both glucose and mannose go through degradation to give arabinose.
The Kiliani-Fischer synthesis converts arabinose into a mixture of glucose and mannose.

D-erythrose comes from degradation of d-arabinose.

Give the structure of d-ribose by drawing out the reactions.

The oxime is converted to a nitrile by acetic anhydride.

The equations for the individual reactions in the degradation of d-arabinose to d-erythrose can be given using the following sequence of reagents.

There are no mechanisms required.

All degraded should be written out to (+)@glyceraldehyde.

In 1891, the structures of glucose and the seven other daldo-hexoses were determined using only simple chemical reactions and clever reasoning.

He received a prize for this work.
D-glucose is an aldohexose, and he degraded it to ( +)-glyceral dehyde.

Arabinose is the same as aldopentose after degradation.

Aldaric acid is an oxidizer of arabinose.

Arabinose gives the aldotetrose erythrose.

The hydrolyze gives the same anomer as the starting material.

The silyl ethers are hydrolyzed by floride salts.

There are three common bonding arrangements in naturally occurring disaccharides.

The oxygen atom on C4 of the second sugar is bonded to the anomeric carbon.

The prime symbol indicates that C4 is on the second sugar.

The oxygen atom on C6 of the second sugar is bonded to the anomeric carbon.

The oxygen atom bonds the anomeric carbon of the first sugar to the anomeric carbon of the second sugar.

We will look at some naturally occurring disaccharides.

An acetal is a sugar and alcohol mixture.

The alcohol is a disaccharide.

The 1,4' link is the most common linkage.

The oxygen atom on C4 of the second ring is bonded to the anomeric carbon of one sugar.

The anomeric carbon of one unit is linked through a carbon-oxygen bond to another unit.

Its structure is given by (b-d-glucopyranosyl)-b-d-glucopyranose.

A b-d-glucopyranose ring is replaced in its 4-position by an oxygen ring on the left, according to this name.
Cellobiose has aglucose unit in the hemiacetal form and therefore is in equilibrium with its open-chain aldehyde form.

The equilibrium mixture of the two anomers can be seen when sugars are shown with a wavy line.

The first step in making beer is the malting process.

Like cellobiose, maltose has a 1,4' linkage between two units.
The stereochemistry of the glucosidic linkage is different in maltose.

There is a free hemiacetal ring on the right of maltose.

Maltose is a reducing sugar because it is in equilibrium with an open-chain aldehyde.

The structures of the individual mutarotating a and b anomers of maltose can be drawn.

The reduction of Tollens reagent by maltose is shown in the equation.

Lactose is composed of two units.

Lactose is found in the milk of mammals.

A b@galactosidase is needed to hydrolysis of lactose.

Some humans are able to synthesise a b@galactosidase.
Normal infants hydrolyze their mother's milk with the help of this enzyme.

The child stops drinking milk after a while.

In most parts of the world, people don't use milk products after early childhood, and the adult population can't digest Lactose.
Lactose-intolerant infants need to drink soy milk or another formula.

There are two forms of lactose.

The 1,6' linkage is also found in naturally occurring carbohydrates.

The anomeric carbon of one sugar is linked to the oxygen of the other in a 1,6' linkage.
The hydroxy group on C6 is one carbon atom removed from the ring, so this linkage gives a different sort of stereochemical arrangement.
A b@1,6' glucosidic linkage is found in gentiobiose.

The 1,6' linkage is a rare one in disaccharides.

Section 23-13B states that branching in amylopectin occurs at 1,6' linkages.

There is a 1,1' linkage between sugars and their carbon atoms.

The linkage is in the a position with respect to the glucose ring and the b position with respect to the fructose ring.

There are two monosaccharide units in sucrose.

Sucrose does not reduce Tollens reagent and it cannot mutarotate because neither ring is in equilibrium with its open-chain aldehyde or ketone form.
It is more useful for on the other side because both units of the two sugars are glycosides.
Even though it is a nonreducing sugar, a reducing sugar ends.
Common names are not reliable.

The most common form of invert sugar is honey, a supersaturated mixture of sugars.

Tollens reagent reacts with formula C12H22O11 to form a silver mirror.

A b@galactosidase hydrolyzes it to d-galactose and d-mannose.
Propose a structure for something else.

The formula shows that this is a disaccharide.

Blood types O, A, B, andAB are linked by a b@galactosidase.

One of the hexoses must be in a free hemiacetal form since the original carbohydrate is a reducing sugar.
The surface of the red blood cells are made of Galactose.

The type O cells have no antigenic car.

The point of attachment of the bond to mannose is shown in the procedure.

All of the hydroxy groups are methylated except C1 and C5.
The hemiacetal of the pyranose ring is formed by acetylgalactosamine and Type B and C5 oxygen.
All cells have an antigenic galactose.

The structure is called the universal and systematic name.

There is no reaction when trehalose is treated with a b@glucosidase.

Provide a complete structure and systematic name for trehalose.

Tollens reagent is not reduced by Raffinose.

d-glucose, d-fructose, and d-galactose are produced by complete hydrolysis of raffinose.
An a@galactosidase hydrolyzes it to d-galactose and sucrose, which is unaffected by treatment with a b@galactosidase.
Give a systematic name for melibiose and determine the complete structures of raffinose.

There are hundreds or thousands of sugar units linked together.

All the anomeric carbon atoms of the polysaccharides are involved in the acetal glycosidic links.
Polysaccharides give no reaction with Tollens reagent.

Plants usecellulose as a structural material to support their weight.

Roughly 50% of dry wood and 80% of cotton fiber is made from wood.

d-glucose units are linked by b@1,4' glycosidic bonds.

This bonding arrangement is very stable and rigid, making it a good structural material.

Humans and other mammals don't have the b@glucosidase needed to hydrolyze cellulose, so they can't use it for food.

Several groups ofbacteria and protozoa can hydrolyze.
Colonies of thesebacteria are found in the gut of ruminants.
When a cow eats hay, the bacteria convert some of it to food.

A fiber of insoluble cellulose is regenerated when a solution of an aqueous sodium bisulfate is held.

The thickness of cotton is the same as that of rayon, but the graduated nature of the thread makes it much stronger.

Plants use a substance to store energy.

When treated with acid, it is pro tose, sucrose, and other sugars.

The stereochemistry of the linkage is different.

Amylose around teeth and protectsbacteria has a@1,4' links.

There are some striking physical and chemical differences between the two.

hydrogen bonding is increased with a@1,3' linkages.
Candy makers use water.
Amylose is in water, but sorbitol and mannitol lulose are not.
Amylose is not stiff and sturdy ascellulose is.
Amylose is an excellent food source.
The a@1,4' glucosidic linkage is easily hydrolyzed by gum becausebacteria cannot easily a@glucosidase, found in all animals.

The basis of dextran can be found in the structure of amylose.

The inside of the helix is the right size to accept an I2 molecule.

A dark blue charge-transfer complex is formed by the amylose helix.

The material to be tested is added to a solution.

The blue complex with amylose can be formed if the oxidizer oxidizes some of the iodide.

There is a difference between amylose and amylopectin because of the branched nature of amylopectin.

The main chain is connected by another chain at each branch point.
A partial structure of amylopectin leads to rapid weight loss.

The muscles have a large amount of glycogen in them.

Amylopectin is a branched a-1,4' polymer.

The attachment point for another chain is provided by a single a-1,6' linkage at the branch points.
The structure of Glycogen is similar, but it has more branching.

The structure of glycogen is similar to that of amylopectin.

There are many end groups that can be used for quick hydrolysis to provide glucose needed for metabolism.

Chitin forms a matrix in crustaceans.

Chitin is different from the others.
The hydroxy group on C2 of glucose is replaced by an acetyl group.

The b@1,4' links of the glycosidic bonds give the chitin structural rigidity, strength, and stability that surpasses that of cellulose.

The strong, rigid polymer cannot be easily expanded, so it must be shed periodically as the animal grows.

It is tively nontoxic to mammals.

The fully developed animal has physical characteristics.

A frog and a human are both contained in a small part of the genome.

The nucleus is where the permanent genetic code is found in a typical cell.

The molecule of DNA has a weight of up to 50 billion.
Two copies of the daughter cells are created when the cell divides.
The medium for transmission of genetic information from one generation to the next is provided by DNA.

The smaller the RNA molecule, the easier it is to break down.

The nuclear DNA is being decoded and a working copy of it is served by the RNA.
After it has served its purpose, the messenger RNA is cleaved to its component parts, which are available for assembly into new RNA molecules.

The ribofuranoside rings of a nucleic acid are linked by a group ofphosphate ester groups.

There is a genetic component to HIV.

The anti-AIDS structure is similar to the 0 and 1 bits used by drugs to stop reverse transcription.

The structure of individ, the bonding of the monomers into single-stranded nucleic acids, and the base pairing that bind two strands into the double helix of nuclear DNA are considered first.

ribofuranoside units are linked byphosphate esters.

Section 23-8 shows that a nitrogen atom may be present in a glycoside.

A ribonucleoside is a b-d-ribofuranoside, which is a b@glucosidase of d-ribofuranose.

Purines can be used to form waste products.

The four bases make up the ribonucleosides cytidine, uridine, adenosine, and guanosine.

The base and sugar are numbered separately, and the carbons of the sugar are given primed numbers.
The C3 of the ribose ring is the 3' carbon of cytidine.

There are four ribonucleosides.

There are aromatic hydroxy groups in the tautomeric forms of Cytosine, uracil, and guanine.

It is stable to base, but quickly hydrolyzed by acid.

There is a mechanism for acid-catalyzed hydrolysis.

Ribonucleosides require strong acid.

Ribonucleic acid consists of ribonucleosides.

The glycosidic bonds are already used to attach the Heterocyclic bases, so they can't be used to bond this polymer.
The ribonucleoside units are linked.
The ribofuranoside has a 5'@hydroxy group.

The ribonucleotides can be found in any of three states, depending on the solution's pH.

At the neutral pH of 7.4, there is a single protons on the phosphate group.
These groups are written completely ionized.

Major functional differences can be found in the structure of Carbohydrates and Nucleic Acids Ribonucleic acid and deoxyribonucleic acid.

The primary genetic material in living cells is DNA.
A short-lived copy of part of the larger DNA molecule can be found in the synthesis of RNA.
Then, the cellular machinery converts the nucleotide sequence of the RNA molecule into a sequence of amino acids.

The end carbon of ribose and the hydroxy group are on the 3' carbon.

There is a linkage between the 5'@phosphate group of one nucleotide and the 3'@phosphate group of another.

The 5' end of one nucleoside is linked to the 3' end of another by a phos phate ester.

Unless it is in the form of a large ring, a molecule ofRNA has two ends.
There is a free 3' group at one end and a free 5' group at the other.

All of the descriptions of ribonucleosides, ribonucleotides, and ribonucleic acid apply to the components of DNA.

The d-ribose found in the RNA is different from the sugar found in the DNA.

The number 2 means that the oxygen atom is missing.

The presence of uracil inRNA is different to the presence of thymine in DNA.

It is simply uracil with an additional group.
There are four common bases of DNA.

The bases in ribonucleosides and ribonucleotides are similar to these four bases.

The structures show the common nucleosides.
The same structures with different groups are found at the 5' positions.

There are no hydroxy groups on the 2' carbon atoms of the ribose rings in the structure of the DNA.

The bases attached to the deoxyribose units carry the genetic information.

We now consider how the nucleotide sequence is reproduced or transcribed into another molecule.

The hydrogen-bonding interaction between specific pairs of bases is what transfers this information.

Each pyrimidine base forms a stable hydrogen-bonded pair with only one of the two purine bases.

Each purine base has a hydrogen-bonded pair with a specific pyrimidine base.

The maps show that hydrogen bonding takes place between nitrogen and oxygen atoms.

Two hydrogen bonds are joined by a base pair of uracil and adenine.

The lengths of hydrogen bonds have to be the same in order to form a structure.
In 1950, it was suspected that various DNAs, taken from a wide variety of species, had about equal amounts of adenine and thymine and guanine and cytosine.

The rings of the four bases are aromatic.

James D. Watson and Francis C. Crick were the first to use X-ray diffraction patterns to determine the structure of DNA.

They found that there are two hydrogen bonds between the pairs of bases.

One strand runs from the left to the right while the other runs from the left to the right.

There are two strands of DNA with all the base pairs hydrogen bonding together.

The strands are running in opposite directions.

The two strands of DNA are coiled around the same axis and have a 20 A in diameter.

The helix makes a complete turn for every tenth of a second.
The two sugar-phosphate backbones form the vertical double helix in this drawing.
The attractive stacking forces between the pi clouds of the aromatic pyrimidine and purine bases help to stable the arrangement.

Two strands are joined by another.

C. G A.

A strand is assembled.

A A.

A double electron micrograph.

There is a lot of knowledge about the translation of the DNA/RNA sequence of bases into proteins.

The versatile biomolecules serve a variety of additional functions, even though we generally think of them as the monomers that form DNA and RNA.

There are a few additional uses of nucleotides.

The 3'@ and 5'@hydroxy groups are both esterified by the samephosphate group.

One of the main oxidation-reduction reagents in biological systems is nicotine adenine dinucleotide.

One ribose has nicotinamide and the other has adenine.

It is possible that adenosine acts as a neurotransmitter that causes sleep.

The wakefulness cal oxidation of an alcohol is caused by the oxidizing agent in the biologi receptor being NAD+.

The nicotinamide portion of NAD is shown in the picture.

The alcohol dehydrogenase is the catalyst for this reaction.

Most anhydrides are exothermic.

The products that are used in the process are adenosine diphosphate.

The heat of hydration explains the exothermic nature of the products.

The heat of hydration is different between the two, with the former being hydrated about as well as the latter.
The three negatively charged groups in ATP are reduced by hydrolysis.
31 kJ of energy per mole ofATP is freed by hydrolysis.
The energy that muscle cells use to contract is the same energy that all cells use to drive their chemical processes.

The acetal form of a sugar is the anomeric carbon of a glycoside.

Oxygen or nitrogen can be used to bond aglycones to sugar.

A dicarboxylic acid is formed by oxidation of carbon atoms.

Reduction of the carbonyl group of a monosaccharide formed a polyalcohol.

A monocarboxylic acid is formed by the oxidation of an aldose.

A monosaccharide has an aldehyde carbonyl group.

Glucosamine is a sugar in which the hydroxy group is replaced by the amino group.

The anomeric carbon is the only carbon with two bonds to oxygen atoms.

The sugar stereoisomers have the same configuration at the anomeric carbon.

Polyhydroxy aldehydes and ketones are derivatives.

The cell walls of plants are made of wood and cotton.

The strength and rigidity of insects and crustaceans is due to the presence of acetylglucosamine.

The loss of a carbon atom is caused by a reaction.

A template for the synthesis of ribo nucleic acid can be found in a biopolymer.
Through uncoiling and the linking of bases, DNA is the template for its own replication.

A sugar that has a hydrogen in it.

The presence of a methylene group or a methyl group is indicative of deoxy sugars.

D-( +)-glucose is the common dextrorotatory isomer.

The asymmetric carbon atom in d-( +)-glyceraldehyde has the same configu ration as the asymmetric carbon atom in sugars.

The sugars in the d series are naturally occurring.

Two monosaccharide molecules are created by the hydrolysis of a carbohydrate.

A base-catalyzed tautomerization that converts aldoses and ketoses with an enediol as an intermediate.

C2 and other carbon atoms are epimerized by this enolization.

There are two sugars at a single asymmetric carbon atom.

If no carbon is specified, it is assumed to be C2.

There are groups on the same side and opposite sides of the projection.

A side derived from sugar.

Nonreducing sugars are stable to base.

An acetal bond is a bond between two monosaccharide units.

The acetal bond from the anomeric carbon of glucose is used in the linkage.

The acetal bond from the anomeric carbon of galactose is used in the linkage.

The projection shows the cis and trans relationships, but it doesn't show the pyranose's positions.

A monosaccharide has a carbonyl group.

A method for longating an aldose.

The carbon atom is added to the aldose to make it two epi meric aldoses.

The asymmetric carbon atom in l-( -)-glyceraldehyde has the same configu ration as the asymmetric carbon atom in sugars.

Nature doesn't like sugar from the l series.

The smaller sugar molecule is given by a carbohydrate that does not undergo hydrolysis.

A change in optical rotation occurs when a pure anomer of a sugar in its hemiac etal form equilibrates with the other anomer to give an equilibrium mixture with an averaged value of the optical rotation.

One of the derivatives of pyrimidine or purine is the aglycone.

It gives two to ten monosaccharide units, but not as many as a polysaccharide.

Many monosaccharide molecules are given by a carbohydrate.

The main structure of a nucleic acid is the sequence of nucleotides.

The genetic characteristics of the nucleic acid are determined by this sequence.

There is a commercial fiber made from regenerated cellulose.

Any sugar that gives a positive Tollens test.

Both aldoses and ketoses give positive Tollens tests.
A biopolymer controls the synthesis of ribonucleotides.
The synthesis of RNA is controlled by the cell's genes.

A method for shortening the chain of an aldose by one carbon atom by treatment with bromine water, followed by hydrogen peroxide and Fe2(SO4)3.

The class of a-1,4'glucose is used in plants and animals.

The d-glucopyranose is a linear a-1,4' polymer.

The d-glucopyranose is a branched a-1,4' polymer.

Branching takes place at a-1,6' glycosidic linkages.

A-1,4' of d-glucopyranose is used for animal storage.

Branching takes place at a-1,6' glycosidic linkages.

A generic term for monosaccharides and disaccharides that are found in foods.

The silver-ammonia complex is used as a test for alde hydes.

A silver mirror is a result of a positive test.
Tollens reagent promotes enediol rearrangements that interconvert ketoses and aldoses.

Both aldoses and ketoses give positive Tollens tests if they are in their hemiacetal forms.

Each skill is followed by problem numbers.

From memory, draw the projections and the chair conformations of the anomers and epimers.
You can name the sugars based on their structure.

Correctly name monosaccharides and disaccharides, and draw their structures from Problems 23-47, 48, 49, 53.

Predict which carbohydrates mutarotate, which reduce Tollens reagent, and which undergo epimerization and isomerization under basic conditions.

Predict the reactions of sugars.

Predict the reactions that convert their carbonyl groups to acetals.

The structure of an unknown carbohydrate can be determined by its reactions.

Determine its ring size from the results of the problems.

You can identify the types of linkages by drawing them.

Draw the structures of the common ribonucleotides and deoxyribonucleotides.

Fructose can be found in many fruits.

The C2 oxygen atom is replaced by a formylated amino group.

The following aldoses can be named using Figure 23-3.

Classify the monosaccharides.

When HCN reacts, give the products expected.

You are aware of the absolute configuration of d-(+)-glyceraldehyde.

Predict the products obtained when d-galactose reacts with each reagent.

The following sugar derivatives can be drawn.

The structures of the following disaccharides can be drawn.

An unknown sugar is isolated from the reaction mixture after a series of Kiliani-Fischer synthesises.

Aldonic acid is created by reacting with bromine water.

HNO3 reacts with aldaric acid.

HNO3 oxidation and ruff degradation give an inactive aldaric acid.

The original sugar is treated with CH3I and Ag2O.

There is a free hydroxy group on C5.

The open-chain form of this sugar is unknown.

To name the sugar, use Figure 23-3.

Give the structure a complete systematic name by drawing the most stable conformation of the most stable form of this sugar.

An unknown reducing disaccharide is unaffected.

One molecule of d-fructose and one molecule of d-galactose is given by treatment with an a@galactosidase.
Give a complete systematic name to this disaccharide if you propose a structure for it.

Does not react to bromine water.

Tollens reagent is reduced to give d-galactonic acid and d-talonic acid.

The open-chain form of tagatose has a projection structure.

Draw the most stable form of tagatose.

The other configuration of the stereoisomer is at this center.

An acetonide can block reaction at the 2' and 3' oxygens of a ribonucleoside.

The tetraisopropyldisiloxanyl group, abbreviated TIPDS, protects two alcohol groups in a molecule.

The structures of the nucleotides can be drawn.

The structure of a four-residue segment of DNA can be drawn.

HIV, the pathogen responsible for AIDS, has a template that is copied into DNA.

The anti-HIV drug AZT (3'@azido@2',3'@dideoxythymidine), which becomes phosphorylated and is incorporated by reverse transcriptase into DNA, is exploited by its lack of selectivity.

The toxicity of mammalian DNA polymerases is low because it has a low affinity for AZT.

Draw the structures of AZT.

Draw the structure of AZT 5'@triphosphate.

Section 19-16) states that exposure to nitrous acid can convert cytosine to uracil.

The mechanism for this conversion should be proposed.

Explain how this conversion would change.

uracil is found in RNA, but not in DNA.

Explain that the nitrous-acid-induced mutations of cytosine to uracil is easier to repair in DNA than it is in RNA.

H. G. Khorana won the Medicine Prize in 1968 for his work on the synthesis of DNA and the decoding of the genetic code.

The 5' OH group of nucleosides were part of the chemistry he developed.

The 5' OH group's trityl ether derivatives are obtained by reacting the nucleoside with trityl chloride, MMT chloride, or DMT chloride.

Aqueous acid can be used to remove the trityl ether derivative.

DMT derivatives hydrolyze fastest, followed by MMT derivatives and trityl derivatives.

The product should be drawn on the 5' oxygen.

Explain why the 5' OH group is not included in the trityl derivative.

Which of the following are acidic, basic, and neutral?

The isoelectric point can be used to predict the charge on an acid.

Show how to combine the two acids in the correct sequence to make apeptide.

The structure of an unknown peptide can be determined using information from terminal residue analysis and partial hydrolysis.

The levels of the most abundant organic molecule in animals are identified in the introduction.

Spider web is composed mostly of fibroin, a protein with a bunch of amino acids.

The amide secondary structure is joined by the individual amino acid subunits.

Figure 24-1 shows the general structure of the arrangement.

The great strength of the molecule is due to the amazing range of structural and catalytic properties.

Spider silk has the same strength as steel, but it has six different functions in living organisms.

The amide linkages are called peptide bonds.

One of the major branches of biochemistry is the study of proteins, and there is no clear division between their organic chemistry and their biochemistry.

In this chapter, we learn about the amino acids.
We talk about how the properties of aProtein depend on those of its constituent amino acids.
These concepts are needed for the study of the function and structure of the human body.

The side chains are replaced on the a carbon atom.

There is a side chain of the amino acid alanine.

The a@amino acids are all different.

The asymmetric a carbon atom is the center of all of the chiral acids.

The sign of the optical rotation, called racemases, is not implied by it.

The compounds carboxylic acids are used by mammals because they combine many of the properties and reactions of amines.

Some unique properties and reactions can be found in the combination of a basic amino group and an acidic carboxyl.
The mammals and show promise as side chains of some acids lend themselves to antibiotics.

The side chains that bond the carbon atoms to the standard amino acids are different.

L-amino acids are the standard for the amino acids.

The table shows the chemical properties of the side chains.

A three-letter abbreviation and a one-letter symbol are given to each of the amino acids.

Proline is different from the other standard acids.

Its carbon atom is fixed in a ring.

Humans are able to synthesise half of the amino acids needed.

Adult humans need about 50 g of complete protein per day.

The amount of human protein that can be synthesised is limited by the amount of incomplete sources, such as proline and glycine.

There are incomplete plant proteins.
Corn and wheat are deficient in lysine.
Corn and rice lack threonine and are low in vitamins.
Among the many essential amino acids, beans, peas, and other legumes are the most complete.

If you eat many different plant foods, you can get an adequate intake of the essential amino acids.

Some foods have some of the same amino acids as others.
Rice and beans are often combined because they are both low in methionine and high in lysine.
Adding milk or eggs to the vegetarian diet is an alternative.

The plant can't make the proteins it needs because it can't get phenylalanine.

The human toxicity of a small amount ofGlyphosate is very low.
Why does this powerful pesticide have little effect on humans?

There are other amino acids found in smaller quantities.

4-Hydroxyproline and 5-Hydroxylysine are hydroxylated versions of standard amino acids.

Some of the less common d enantiomers are found in nature.

In many organisms, d-glutamic acid and d-serine are found.

One of the neurotransmitters in the brain is g@Aminobutyric acid, and b@alanine is a component of thevitamin pantothenic acid.

The NH2) group's structure is ionic and depends on the pH.

The carboxyl group has a carboxylate ion and the amino group has an Ammonium ion.

The main form of the acid depends on the solution's pH.

The molecule has a positive charge.
COOH has a pH 2.
The NH+3 group loses its protons at a rate of about 9 or 10.
The molecule has a negative charge above the pH.

The figure shows a curve for glycine.

The curve begins at the bottom left.
The base is slowly added.
Half of the cationic form has been converted to the zwitterionic form.
All of the glycine is in the zwitterionic form.
Half of the zwitterionic form has been converted to the basic form.
The graph shows that glycine is mostly in the cationic form at pH values below 2.3, and in the zwitterionic form at pH values between 2.3 and 9.6.
We can control the charge on the molecule by changing the solution's pH.
Section 24-4 describes how this ability to control the charge of an anhydride is useful for separation and identification of anhydride from anhydride.

The isoelectric pH is 6.0

An acidic solution has a positive charge in it and a negative charge in it.

The dipolar zwitterion with a net charge of zero is an intermediate pH where the amino acid is evenly balanced between the two forms.

Table 24-2 contains the isoelectric points of the standard amino acids.

The isoelectric pH depends on the structure of the amino acid.

There are acidic isoelectric points around the pH 3.

An acidic solution is needed to prevent deprotonation of the second carboxylic acid group.

There are isoelectric points at pH values of 7.6, 9.7, and 10.8 for basic amino acids.

The weak basicity of the imidazole ring, the intermediate basicity of an amino group, and the strong basicity of the guanidino group are reflected in these values.
In each case, a basic solution is needed to keep the basic side chain neutral.

The other amino acids are neutral.

The COO group is basic.

Explain why arginine acid has a net charge of zero, with a strongly basic isoelectric point, by drawing the resonance forms of a protonated guanidino group.

NH+3 and COO are balancing each other.

A streak of the amino acid mixture is placed in the center of a layer of acrylamide gel or a piece of filter paper wet with a buffer solution.

A potential of several thousand volts is applied to the edges of the gel or paper after two electrodes are placed in contact with it.
Positively charged (cationic) and negatively charged (anionic) amino acids are attracted to each other.
There is no net charge at the isoelectric point.

An example would be a mixture of alanine, lysine, and aspartic acid in a buffer solution.

Alanine has a net charge of zero and is a dipolar zwitterionic form.
lysine is in the cationic form because of the isoelectric pH of 6.
The anionic form of aspartic acid has an isoelectric pH of 2.8.

Alanine does not move because it is at its isoelectric point.

A mixture of alanine, lysine, and aspartic acid does not move when a voltage is applied.

Aspartic acid moves toward the positively charged anode.
The separated amino acids can be recovered by cutting the paper or removing the bands from the gel.
The paper or gel is treated with a reagent such as ninhydrin to make the bands visible if it is being used as an analytical technique.
The positions of the amino acids are compared with those of standards.

At pH 9.7, draw the separation of Ala, Lys, and Asp.

The separation of Trp, Cys, and His at pH 6.0 was drawn.

Naturally occurring amino acids can be obtained by hydrolyzing proteins.

It is often less expensive to synthesise the pure amino acid.
An unnatural enantiomer is needed in some cases.
In this chapter, we look at four ways to make amino acids.
We have already studied all of these methods.

One of the best ways to make amines iseductive amination.

It forms some acids.
An imine forms when an a@ketoacid is treated with ammonia.
The imine is reduced by hydrogen and a catalyst.
The carboxylic acid is not reduced.

The entire synthesis is accomplished by treating the a@ketoacid with ammonia and hydrogen in the presence of a palladium catalyst.

The product has a racemic a@amino acid in it.
The reaction shows the synthesis of racemic phenylalanine.

A@ketoglutaric acid is an intermediate in the metabolism of carbohydrates and is used as the aminating agent and reducing agent in Amino Acids, Peptides, andProteins.

The pure l enantiomer is the product of this reaction.

L-glutamic acid is used as the source of the group.

The reaction shows the synthesis of aspartic acid using a nitrogen source.
The pure l enantiomer of the product is given by the enzyme-catalyzed biosynthesis.

The Hell-Volhard-Zelinsky reaction can be used to introduce bromine at a position of a carboxylic acid.

A large amount of ammonia is used to convert the racemic a@bromo acid to a racemic a@amino acid.

In Section 19-11, we saw that direct alkylation is often a poor synthesis of amines, giving large amounts of overalkylated products.

In this case, the reaction gives acceptable yields because a large amount of ammonia is used.
The product has a carboxylate ion in it.
The following sequence shows the bromination of 3-phenylpropanoic acid and the displacement of bromide ion to form the ammonium salt of racemic phenylalanine.

In 1850, the first known synthesis of an amino acid took place in the laboratory of Strecker.

Strecker added acetaldehyde to the solution.
The product was a@amino propionitrile.

Next, the mechanism is shown.

The aldehyde reacts with ammonia.
The imine is a nitrogen analogue of a carbonyl group.
The a@amino nitrile is given by the attack of cyanide ion on the imine.
This mechanism is similar to that for formation of a cyanohydrin, except that in the Strecker synthesis ion attacks an imine rather than the aldehyde itself.

The ion attacks the imine.

The a@amino nitrile is given an a@amino acid in a separate step.

CH3 is the side chain when CHO undergoes Strecker synthesis.

Isoleucine should be given by CHO.

How would a Strecker synthesis be used to make phenylalanine?

The mechanism for each step in the synthesis should be proposed.

Racemic products are produced by all of the laboratory products described in Section 24-5.

The l enantiomers are biologically active.
It is possible that the d enantiomers are toxic.
If the product is to have the activity of the natural material, pure l enantiomers are needed.

We must be able to resolve a racemic acid into its enantiomers.

The methods we have already discussed can be used to resolve amino acids.

Two diastereomeric salts are formed if a racemic amino acid is converted to a salt.
The salts can be separated by physical means.
Pure enantiomers are regenerated from the separated diastereomeric salts.
Strychnine and brucine are naturally occurring bases, and tartaric acid is used to resolve racemic mixtures.

There are specific catalytic activities for the kerosines.

The acyl group can be cleaved from just the molecule having the natural (l) configuration by an acylase.
The d-amino acids are unaffected because the enzyme doesn't recognize them.

The mixture of the two acids is easy to separate.

There is a hog kidneys acylase that deacylates only the natural l-amino acid.

Both amines and carboxylic acids undergo many standard reactions.

The conditions for some of these reactions must be carefully selected so that the carboxyl group reaction is not interfered with.

Two of the most useful reactions are acylation and esterification of the carboxyl group.

These reactions can be used to protect either the carboxyl group or the amino group while the other group is being modified.
There are specific reactions that occur to the a@amino acid structure.
Section 24-7C discusses the formation of a colored product on treatment with ninhydrin.

Like monofunctional carboxylic acids, amino acids are esterified by treatment with a large excess of alcohol and an acidic catalyst.

It does not interfere with esterification.
The following example shows the process of esterification.

The carboxyl group can be prevented from reacting in a way that is undesirable with the use of derivatives of amino acids.

The most common protecting groups are ethyl and benzyl.
Aqueous acid hydrolyzes the ester.

The benzyl group is converted to toluene and left with the deprotected amino acid.

The ease of formation of benzylic intermediates is what determines the mechanism of hydrogenolysis.

There is a mechanism for acid-catalyzed hydrolysis.

Give equations for the formation and hydrogenolysis.

As an acylating agent, decarboxylation is similar to the alcohol esterification of the carboxyl group of an amino acid.

Acylation is done to protect biological processes.
There is a wide variety of acid chlorides and anhydrides used for acylation.
The decarboxyl carbonyl derivative is often used as a protecting group in the synthesis of peptides.

The amide half of a carbamate ester is more easily protected than most other amides.

The half of this urethane that undergoes hydrogenolysis is a benzyl ester.
benzyloxycarbonyl amino acid gives an unstable acid that quickly decarboxylates.

The purple dye produced by ninhydrin is the same as the original one.

The side chain is lost as an aldehyde.

A wide range of substrates can be detected with the reaction of ninhydrin.

If a kidnapper touches a ransom note with his fingers, the ridges on his fingers will leave traces of a substance from his skin.
Treatment of the paper with ninhydrin and pyridine causes it to turn purple.

There is a negative charge in the purple anion.

There are many common reactions of amines and acids.

There are two monomers that combine to form polymers.

The various types of proteins are essential to life.

The formation of peptide bonds is the most important reaction.

The loss of water can cause amines and acids to form amides.
Industrial processes often make amides by mixing acid and amine and heating the mixture to drive off water.

Amides are the most stable acid derivatives.

The stability is due to the strong resonance interaction between the nonbonding electrons on nitrogen and the carbonyl group.
The partial double-bond charac ter has restricted rotation.

Six atoms are held in a plane by this partial double-bond character.

An amide linkage can be formed by having both an carboxyl group and an amino acid.

The carboxyl group of another molecule condenses under the proper conditions.
Although it has a special name, a peptide bond is the same as other amide bonds we have studied.

Any number of amino acids can be bonded in a continuous chain.

The names of the amide linkages are reflected in the names of the peptides.

The following dipeptide is called alanylserine.

This is a difficult name.

A three-letter abbreviation is more convenient than a shorthand system.
The first three letters of the name are given in these abbreviations.
The N and C end points are arranged from the left to the right.

The single-letter symbols are widely used.

There are Amide linkages that form the basis of the amino acid chains.

A second kind of bond is possible.

Mild oxidation forms a disulfide linkage between the two thiol molecules.

The disulfide is cleaved by a mild reduction.

There are groups that give disulfide-linked bridges.

Orexin A is a pair of acids.
cystine is a disulfide-linked dimer of cysteine.

Two cysteine residues may form a disulfide bridge within a single peptide chain.

A nonapeptide eating, hoping to learn more about with two cysteine residues linking part of the molecule in a large causes and potential treatments for ring.
Anoremia nervosa is often connected by arrows in drawing the structure of a complicated peptide.

There is a difference between a free carboxyl group and a primary amide.

The molecule is held in a large ring by a disulfide linkage.

The structure of a more complex peptide hormone is shown in Figure 24-10.

The A and B chains are joined by disulfide bridges, and the A chain has an additional disulfide bond that holds six amino acid residues in a ring.
Both chains have the C-terminal amino acids as their primary amides.

Two chains are joined at two positions by disulfide bridges, and a third disulfide bond holds the A chain in a ring.

Disulfide bonds make hair tough and rigid.

The disulfide bridges are cleaved.
These new positions hold the hair in a bent position.

There is a complicated organic structure to lnsy.

Chemists have come up with a way to determine the sequence of the amino acids.
Some of the most common methods will be considered.

Break all the disulfide bonds, open any disulfide-linked rings and separate the individual peptide chains are the first steps in structure determination.

The individual peptide chains are analyzed separately.

Reducing cystine bridges to the thiol form is easy.

There is a tendency to re-form disulfide bridges.
The disulfide linkages are oxidized with peroxyformic acid.

The structure of each chain must be determined once the disulfide bridges have been broken.

The first thing to do is to find out which of the two are present.
The peptide chain is completely hydrolyzed by boiling it for 24 hours.

The components of the hydrolysate are dissolved in a buffer solution and separated in an ion-exchange column.

The solution emerging from the column is mixed with ninhydrin to give it a purple color.

The absorption of light is recorded as a function of time.

The retention time is determined by the purity of the amino acids.

The retention times of the amino acids in the sample are compared to known values.
The area under each peak is related to the amount of amino acid present in that peak.

Figure 24-13 shows a standard trace of an equimolar mixture of amino acids, followed by the trace produced by human bradykinin.

The composition of human bradykinin can be determined with the use of an amino acid analyzer.

The sequence is destroyed.

We must leave the rest of the chain intact in order to determine the sequence.
The process of separation and identification of the cleaved amino acid can be repeated on the rest of the chain.
One method may be used for each end of the peptide, since the N and C ends may be cleaved.

Acid hydrolysis is followed by the treatment of a peptide.

There are three stages to this reaction.

The free group of the N-terminal amino acid reacts with phenylisothiocyanate to form a phenylthiourea.

The shortened peptide chain is expelled by the phenylthiourea.

The phenylthiohydantoin isomerizes to the more stable thiazolinone.

The free group on phenyl isothiocyanate gives a phenylthiourea after a protons transfer.

In acid, the isomerizes to the stable phenylthiohydantoin.

The phenylthiohydantoin derivative is identified by the way it is compared with the standard amino acids.

The identity of the original N-terminal amino acid is given by this.
The Edman degradations are used to identify additional amino acids in the chain.

Several types of automatic sequencers have been developed, and this process is well suited to automation.

The first two steps are shown in Figure 24.

The sample is treated with peroxyformic acid to convert the disulfide bridge to cysteic acid.

The first two steps are related to oxytocin.

Edman degrades the N-terminal amino acid and forms its phenylthiohydantoin derivative.
For the next step, the shortened peptide is available.

Edman degradations could sequence any length.

Further accurate analysis becomes impossible after about 50 cycles of degradation.
A small peptide such as bradykinin can be completely determined by Edman degradation, but larger proteins must be broken into smaller fragments before they can be completely sequenced.

The peptide is treated with 2,4-dinitrofluorobenzene and then hydrolyzed by reaction with 6 M.

The 2,4-dinitrophenyl derivative is recovered and identified as the N-terminal amino acid.

There is a mechanism for the reaction of the N terminus of the peptide with 2,4-dinitrofluorobenzene.

There isn't an efficient way to sequence several amino acids from the C terminus.

There are two products, the free C-terminal amino acid and the shortened peptide.
The new C terminus of the shortened peptide has been cleaved by further reaction.
The entire peptide is s hydrolyzed.

It's difficult to determine if a certain amount of a certain amount of a certain amount of a certain amount of a certain amount of a certain amount of a certain amount of a certain amount of a certain amount of a certain amount of a certain amount of a certain amount of a certain amount There is a clotting second in the chain.

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The entire structure of theProtein is deduced by fitting the short chains together like pieces of a jigsaw puzzle.

There is a mixture of short fragments resulting from the different positions of the acid-catalyzed cleavage.

The chain has predictable points in the chain.

The chain is left at the carboxyl groups of the basic acids.

The chain at the carboxyl groups of the aromatic amino acids is called chymtRYPSIN.

Let's use an example of partial hydrolysis to show how it can be used.

A simple example of how a structure can be pieced together from fragments is provided by roxtocin.

The disulfide bridges may be linked by the two Cys residues in oxytocin.

By measuring the molecule's weight, we can see that it contains only one of the two peptide units.

The peptide hormone vasopressin is partially hydrolyzed after being treated with peroxyformic acid.

The fragments have been recovered.
A structure for vasopressin should be proposed.

Total synthesis of peptides is not an economical method for commercial production.

The important peptides are usually derived from biological sources.
It was taken from the pig pancreas.
The quality and availability of peptide pharmaceuticals have improved.
Amino Acids, Peptides, andProteins are inserted into a bacterium to cause it to produce aProtein.

An important area of chemistry is laboratory peptide synthesis.

If the synthetic peptide turns out to be the same as the natural one, it proves that the structure is correct.

The synthesis provides more products.
Synthetic peptides can be made with altered amino acid sequence to compare their biological activity with natural peptides.
The critical areas of goat's milk can be pointed out by these comparisons.
Hemophiliac factor may suggest causes and treatments for genetic diseases with similar VIII and tissue abnormal peptides.

Peptide synthesis requires the formation of amide bonds between the proper amino dissolving clot.

We would form an amide with simple acids and amines by converting the acid to an activated derivative.
Adding amine and vaccines for diseases.

Genetically modified yeasts and tobacco.

There is a carboxyl group and an amino group in each of the acids.

The carboxyl group reacts with its own group.
Every conceivable sequence can be formed if we mix some amino acids and add a reagent.
There are side chains that might interfere with peptide formation.
There is an extra carboxyl group and an extra amino group inglutamic acid and lysine.
As a result, peptide synthesis always involves the formation of desired bonds and the blocking of unwanted bonds.

Chemists have developed many techniques.

They used typical solution techniques before 1963.

The chemists would apply protecting groups, add activated groups, and then purify the product.

Robert Bruce Merrifield of Rockefeller University developed a method for making peptides without having to purify the intermediates.

He attached the growing chains to the beads.
The excess reagents are washed away by rinsing the beads.
Merrifield was able to synthesise ribonuclease in 6 weeks using this machine.
Merrifield won the chemistry prize in 1984.

The way we usually draw peptides is to start from the C end and work toward the N end, which is the opposite of Merrifield's method.

The protected C-terminal amino acid is attached to the bead.

The NH2 group must be protected.

After the protecting group is removed, the next protected acid is coupled to the first.
Until the entire peptide is formed, there are many more deprotection andcoupling reactions.
It is cleaved from the bead.

Attach the protected C-terminal amino acid to the bead.

Then de protect the next protected amino acid.

The finished peptide can be cleaved from the bead.

We will only consider one set of reagents for each step.

Regardless of the specific reagents, the general principles are the same.

Solid-phase peptide synthesis requires three reactions.

These reactions attach the first protected amino acid to the solid support and form the bonds between the amino acids.

The synthesis is done in the reverse direction.

It begins at the C end and ends at the N end.

Some of the aromatic rings have chloromethyl groups, which is found in a special polystyrene bead.

The chloromethyl groups are similar to other benzyl halides.

The carboxyl group of an N-protected amino acid is what gives the polymer it's ester.
The alcohol part of an ester protecting group for the carboxyl end of the C-terminal amino acid is served by the polymer.
If the chloromethyl groups are attacked, the amino group must be protected.

The chain is built after the C-terminal amino acid is fixed.

The Fmoc group is made up of NH2 groups.

The structure of a protected amino acid is shown below.

We will usually refer to it as Fmoc.

The!NH2 group of the protected amino acid is now an amide.

The Fmoc protecting group is easy to remove.

Most chemists don't make their own Fmoc-protected amino acids.

They buy and use commercially available Fmoc amino acids because they use all their protected form.

The Merrifield procedure requires a final reaction.

The amine and the acid couple form an amide.

It is not as complicated as it may seem.

The activated acyl derivative of the acid is given by the carboxylate ion.
The activated derivative reacts quickly with the amine.
DCU is an excellent leaving group in the final step.

For clarity, the cyclohexane rings are small.

At the end of the synthesis, the ester bond is cleaved.

The amide bonds of the peptide are more difficult to cleave than the ester bonds.

Solid-phase synthesis goes C S N.

Remove the Fmoc group from the N terminus and add the next Fmoc-protected amino acid with DCC.

Propose a way to make acetic acid and aniline work together.

An example is presented to show how the procedures are combined in the Merrifield synthesis.

A simple tripeptide with no problematic side chains will be considered.

The way we write the peptide structure leads to the opposite direction of the solid-phase synthesis.

The first step is attachment of the N-protected C-terminal amino acid.

Ppiperidine cleaves the Fmoc protecting group of phenylalanine so that it can be coupled with the next one.

Vline is added in its N-protected Fmoc form so that it can't couple with itself.

The chain is protected by treatment with piperidine.

The N-protected Fmoc-alanine and DCC are added.

The DMF should be used to protect the amino group at the end of the growing chain.

Add the next Fmoc-amino acid.

The final Fmoc protecting group must be removed and the peptide cleaved once it is completed.

The Fmoc protecting group is removed when Anhydrous HF cleaves the ester linkage.

Depending on their chemical composition, their shape, or their function, there are different types of proteins.

In a biochemistry course, the composition and function of genes are treated.
We briefly look at the types of proteins and their classifications.

All of the structures we have considered are simple.

Some examples are bradykinin and ribonuclease.

Structural parts of the organisms are what they function as.

keratin is found in hooves and fingernails.

They function as hormones or transport proteins.
The body uses hormones to regulate its processes.
Diabetes is a condition in which the body does not produce enough of the sugar in the blood.
Transport proteins can be found in the blood or in the cell.
hemoglobin transports oxygen from the lungs to the tissues.

Each level has a role to play in determining the function.

This definition also includes the sequence of disulfide bridges.

The primary structure determines the properties of theProtein.
The proper primary structure is what determines folding, hydrogen bonding, and catalytic activity.

We often think of peptide chains as linear structures, but they tend to form orderly hydrogen-bonded arrangements.

H) hydrogens.

The side chains on the outside of the helix are similar to the thread on a right-handed screw.

The a@helical structure is where most of the globular proteins are found.

A side-by-side arrangement of hydrogen bonds can be formed by segments of peptides.

Green atoms represent side chains in the space-filling structure.

Silk fibroin is the main Fibroin in the silks of insects and arachnids.

The arrangement is made of pleats.

There is a chance that the secondary structure of aProtein may not be the same throughout its length.

Some parts may be curled into a helix while others are lined up in a sheet.

There may be no orderly secondary structure in parts of the chain.
The helix or pleats of the molecule allow it to fold into its shape.

The a@helical structure of some parts may be different from the other parts.

The tertiary structure includes the secondary structure and the folds in between.

There are segments of a helix with random coil at the points where the helix is folded.

The X rays that are appropriate to be Coiling of an enzyme can give three-dimensional shapes that can be diffracted by the regular atomic spac catalytic effects.

There are not all proteins with quaternary structure.

Those that associate together are the ones that do.
hemoglobin, the oxygen carrier in the blood, is made up of four peptide chains.

The correct structure of a molecule is needed for it to be biologically active.

The disulfide bridges that link the cysteines on the chains must be correct.

The secondary and tertiary structures are important.
The appropriate areas of a helix and pleats are needed for the folding of theProtein.
The active site must have the right shape with the right functional groups.

The right combination of individual peptides is required for conjugated and multichain proteins.

The levels of structure are maintained by weak solvation and hydrogen-bonding forces.

The most common factors that cause denaturation are heat and pH.

Egg white cooking is an example of high temperature denaturation.

The rubbery mass can be produced when egg white is heated.
There are different ways to resist the heat.
Egg albumin is sensitive to heat, butbacteria that live in hot springs can retain their activity in boiling water.

Some of the side-chain carboxyl groups lose their ionic charge when they are subjected to an acidic pH.

Changes result in denaturation.
In a basic solution, deprotonated groups lose their ionic charge and cause changes to their structure.

Milk becomes sour because of the conversion of sugars to acids.

Chunks of milk are denatured and precipitated when the pH is acidic.

Some proteins are more resistant to basic conditions than others.
amylase andtrypsin remain active under acidic conditions in the stomach, even at a pH of 1.

denaturation is irreversible in many cases.

Egg white does not become raw when it is cooled.
Curdled milk does not break down when it is neutralized.

The egg white doesn't become clear when it cools down, but it can be reversed if theprotein has undergone mild dena.

When the precipitatedProtein is redissolved in a solution with a lower salt concentration, it usually regains its activity.

People thought that all infectious diseases were caused by microbes.

They were aware of diseases caused by organisms.
No one had isolated or cultured the strange diseases.
The brains of the victims all had plaques of amyloid.

Workers studying these diseases thought there was an infectious agent involved (as opposed to genetic or environmental causes) because they knew that scrapie and TME could be spread by feeding healthy animals the ground-up remains of sick animals.

Slow viruses were blamed for these diseases.

Stanley B. Prusiner, a neurologist at the University of California at San Francisco, made a Homogenate of scrapie-infecting sheep brains in the 1980's and found that the remaining material was still infectious.

He found a sample of the human brain that was still infectious.
It was suggested that scrapie and similar tissue.

Most of the workers who were skeptical of Prusiner's work came to the same conclusion after repeating his work.

The 1998 Nobel Prize in Medicine or Physiology was won by Prusiner.

Prusiner's work has made prion diseases more important because of their threat to humans.

Some cows in the United Kingdom developed "mad cow disease" in 1996 and eventually died from it.

It is a misfolded, denatured version of a normal protein that forms amyloid plaques in the brains of animals that have been exposed to it.

When an animal ingests food, it resists digestion.
The infectious prion does not cause the host's immune system to attack the pathogen because it is a misfolded version of a normal protein.

When the abnormal prion interacts with the normal version of the molecule on the nerve cells, it causes them to change their shape.

We don't know much about this part of the process.
The newly misfolded molecule causes more molecule to change shape.

The plaques and tissue associated with TSEs are caused by the build up of the abnormal protein in the brain.

We used to think that a correct primary structure would fold into the correct tertiary structure and remain that way.

Prion diseases have shown that there are many factors that can cause the folding of a molecule, and that the folding of the molecule can have a major effect on its biological properties.

The region of the enzyme that makes the reaction happen.

A synthesis is patterned after a biological one.

The synthesis of amino acids by reductive amination is similar to the production ofglutamic acid.

All of the essential amino acids are provided by the right proportions of the right kinds of the right kinds of the right kinds of the right kinds of the right kinds of the right kinds of the right kinds of the right kinds of the right kinds of the right kinds of the right kinds of the

Meat, fish, milk, and eggs are examples.

Most plant proteins are not complete.

There is a sugar, nucleic acid, lipid, or metal ion.

The C terminus is usually on the right.

The rest of the peptide is linked by the C-terminal amino acid.

As in cooking an egg, detaturation can be reversed.

Mild oxidation of their thiol groups to a disulfide formed a bond between two cysteine residues.

A method for removing the N-terminal amino acid from a peptide without damaging the rest of the chain.

The phenyl isothiocyanate is used to convert the N-terminal amino acid to the phenylthiohydantoin derivative.
The Edman degradation can be used to determine the sequence of many residues.

A procedure to separate charged molecule by their migration in a strong electric field.

The average charge on the molecule governs the direc tion and rate of migration.

The enantiomers of an acid can be acylated and then treated with a drug.

The acyl group is hydrolyzed, but it does not react with the d-amino acid.
The mixture of the two acids is easy to separate.

The diet needs to provide ten standard amino acids that are not biosynthesized by humans.

A class of proteins that are insoluble in water.

A class of proteins that are spherical.

The lower the molecular weights, the more water is in it.

On the next turn, H hydrogens.

This arrangement is stable because of hydrogen bonding.

benzyl esters can be cleaved by catalytic hydrogenolysis.

The pH is the point at which an amino acid does not move.

The average charge on the molecule is zero, with most of the molecule in its zwitterionic form.

There is a stereochemical configuration similar to that of l-(-)@glyceraldehyde.

The l configuration is what most naturally occurring amino acids have.

The N terminus is usually on the left.

The rest of the peptide is linked by the carboxyl group of the N-terminal amino acid.

There is a small polypeptide with four to ten amino acid residues.

There are amide bonds between the carboxyl group of the neighboring amino acid and the amino acid group.

There are linkages between the two acids.

The two-dimensional peptide is lined up side-by-side.

The side chains are arranged on the sides of the sheet.

There is a peptide containing many acids.

The structure of a molecule is made up of the sequence of acids and disulfide bridges.

amyloid plaques and destruction of nerve tissue are thought to be caused by an infectious agent that promotes misfolding and polymerization.

Prosthetic groups include sugars, lipids, nucleic acids, and metal complexes.

The weights of the polypeptides are higher than 5000 amu.

A type of structure in which the chain is not curled into a helix or lined up in a sheet.

There are segments of random coil that fold the molecule into its shape.

A method for determining the N-terminal amino acid.

The peptide is treated with 2,4-dinitrofluorobenzene.
The rest of the peptide is destroyed in the process of derivatizing.

The secondary structure is usually a helix or random coil.

The order in which amino acids are linked together is a word.

To determine the sequence of a peptide.

There are only two types of Proteins, composed of only amino acids.

The peptide is cleaved from the solid support when it is complete.

The 20 a@amino acids are found in almost all naturally occurring proteins.

A@amino acids can be synthesised by reaction of an aldehyde with ammonia and cyanide ion.

It is possible to remove and identify the residue at the N and C end points.

Transamination is a common method for the synthesis of amino acids.

A structure with an overall charge of zero but two negatively charged substituent.

The majority of the amino acids are in zwitterionic forms.

Each skill is followed by problem numbers.

Draw the structures from the names of the two acids.

Information from terminal and partial hydrolysis can be used to determine the structure of a peptide.

The isoelectric point of phenylalanine is 5.

The major form of phenylalanine has pH values of 1, 5.5, and 11.

Take the complete structure of the peptide and draw it.

How would you make any of the standard amino acids?

You can use any necessary reagents.

Suggestions for a method for the synthesis of the natural l enantiomer of alanine from the readily available l enantiomer of lactic acid.

The Strecker synthesis can be used to make isoleucine.

The structures for the following peptides should be written.

Tell us if the peptide is acidic, basic, or neutral.

The structure is drawn in a different way.

You need to identify and label each acid.

The full name and abbreviated name should be given.

phenyl alanine, aspartic acid, and methanol are given by complete hydrolysis of aspartame.

There is no effect on aspartame.
The phenylthiohydantoin of aspartic acid is given after treatment with phenyl isothiocyanate.

There is a proposal for a structure for aspartame.

One Gly, two Ala, one Met, and one Phe are found in an unknown peptide that has been shown to be a pentapeptide.

The first free amino acid released after treatment of the original pentapeptide is alanine.

The structure for the unknown pentapeptide should be proposed.

The steps and intermediates are shown in the picture.

There are functional groups other than carboxyl groups at the C terminus.

The hydrolysate is found to contain Ala, Phe, Val, and Glu.

There is an unknown pentapeptide that gives leucine, valine, and isoleucine.

When the hydrolysate is neutralized, there is no smell of ammonia.

A long, flexible amide linkage is usually used to bind the peptide to the active sites of the enzymes.

It can be drawn in both of its forms.

Show how a disulfide bridge can be formed with two Cys residues.

Give a balanced equation for a hypothetical oxidation or reduction of an aldehyde by lipoic acid.

Histidine is found at the active sites of many enzymes.

Histidine can be used to transfer protons from one location to another.

The basic nitrogen atom of the histidine Heterocycle is not shown.

The stable form of histidine is shown in resonance forms.

Ornithine has an isoelectric point.

There is a structure for ornithine.

Glutathione (GSH) is a tripeptide that acts as a mild reducing agent to detoxify peroxides and maintain the cysteine residues of hemoglobin and other red blood cell proteins in the reduced state.

Glutathione gives Gly, Glu, and Cys.
Glycine is the first free amino acid to be released.

The 2,4-dinitrophenyl derivative ofglutamic acid is given by the treatment of glutathione with 2,4-dinitrofluorobenzene.

phenyl isothiocyanate does not give a recognizable phenylthiohydantoin.

The structure for glutathione should be consistent with this information.

Glutathione disulfide is oxidation of glutathione.

Write a balanced equation for the reaction of glutathione with hydrogen peroxide and propose a structure for glutathione disulfide.

An unknown basic decapeptide gives Gly, Ala, Leu, Ile, Phe, Tyr, Glu, Arg, and Ser.

The terminal analysis shows that the N and C are related.
The following results are given by terminal residue analysis.

A carboxylic acid can be activated in a number of ways.

Explain the difference between a simple alkyl ester and an NHS ester.

There is a mechanism for the reaction shown.

Sometimes a drug or an insect needs the unnatural d enantiomer of an acid.

The d-amino acids are rarely found in natural proteins.
One of the possible methods is a synthetic scheme.

In this scheme, draw the structures of intermediates 1 and 2.

A student used the instrument to suppress the DOH solvent peak after taking the phenylalanine in D2O solution.

The spectrum is shown.
The peaks' relative areas are 5:1.

Unsaturations affect the properties of oils and fats.

Saturated fats have the same properties as those of polyunsaturated oils and partially hydrogenated vegetable oils.

Explain how detergents and soaps work.

The most important product of whaling was whale oil.

The whalers hunted many species that were close to extinction.

Your mother is rushed to the hospital to have her gallbladder removed.

There was cholesterol in whale oil.
You use carnauba wax to wax your car.
When your father's lamp oil was replaced by kerosene, it was cheaper to use a prostaglandin to lower his blood pressure.
An artist uses turpentine to clean her.
After painting the brilliant autumn colors, whale oil was also used.

The use, misuse, or manipulation of lipids are all involved in these actions.

Steroids, pros mechanical parts, including early auto taglandins, fats, oil, waxes, and even the colorful carotenes in the falling matic transmission fluid.
There are synthetic oils and leaves.
There is no need for compounds according to their functional groups in our study of organic chemistry, because classified lubricants are available for all of these applications.
Lipids are classified by whale oil or other whale products.

A wide variety of functional groups are contained in many types of compounds.

A solution of lipids can be prepared by grinding a T-bone steak in a blender and then pureeing it with chloroform or diethyl ether.
A lot of compounds would be contained in the solution of lipids.
The large family of lipids has been divided into two major classes.

Waxes and glycerides are two types of alcohols.

Many so-called "simple" lipids are quite complex.

Steroids, prostaglandins, and terpenes are important groups of simple lipids.

Simple lipids are hard to hydrolyzed.

They are found in nature and serve a number of purposes.

It is possible that it will amplify high-frequency sounds for locating prey.
The carnauba plant makes a waxy substance to protect its leaves from excessive loss of water.
Waxes are found in arthropods, mammals' fur, and birds' feathers.
Theparaffin wax used to seal preserves is a mixture of high-molecular-weight alkanes, which is not a true wax.

Natural waxes were used to make many materials.

Synthetic materials have replaced natural waxes for most of these uses.

The OH groups have been esterified.

Plants often have a wax coating on their leaves.

Most of the triglycerides derived from mammals are fat.

The warm body temperature of the animal allows for movement, even though the fats are solid at room temperature.
Corn oil, peanut oil, and fish oil are some of the oils that are found in plants and animals.
A fish needs liquid oils because it can't move if its triglycerides solidify when it swims in a cold stream.

Plants and animals use fat and oils for long-term energy storage.

The metabolism of a gram of fat releases about 9 food calories, but each gram of sugar, starch, orProtein releases only about 4 food calories of energy.

The two-carbon acetic acid units make up most of the fat acids.

One or more carbon-carbon double bonds can be found in some of the common fatty acids.

Table 25-1 shows the structures of some common fat acids.

One equivalent of glycerol and three equivalents of myristic acid can be found in Trimyristin.

The structure of trimyristin should be given.

Table 25-1 shows the melting points of saturated fatty acids.

The 18-carbon saturated acid has a melting point of 70 degC, while the 18-carbon acid with a cis double bond has a melting point of 4 degC.
The melting point is lowered because of the "kink" of the double bond.
The uniform zigzag chains of a saturated acid can pack as tightly together as Kinked Molecules.

The cis double bonds of linolenic acid have a bigger effect on the melting point than the trans double bonds of Eleostearic acid.

The geometry of a trans double bond is similar to that of a saturated acid, so it does not cause as much damage to the chain as a cis double bond.

The melting point is lowered by 66 degrees by the cis.

The melting points of oils and fats are dependent on the degree of unsaturation in their acids.

A triglyceride derived from saturated fatty acids has a higher melting point because it is easier to pack into a lattice.

The same number of carbon atoms as tristearin, but triolein has three cis double bonds that prevent optimum packing in the solid state.

The majority of naturally occurring fats and oils are made up of triglycerides.

The individual triglycerides can be mixed with two or three different acids.
Plants and cold-blooded animals have more unsaturations than warm-blooded animals.
Table 25-2 shows the composition of the acids obtained from the hydrolysis of some fats and oils.

A solid lattice does not pack as well as a lattice with O unsaturated fatty acids.

Consumers were unwilling to use vegetable oils because they were used to using white, creamy lard.

This vegetable oil was mostly used for cooking and baking.

Consumers have learned that polyunsaturated vegetable oils may be more healthful, prompting many to switch to natural vegetable oils.

The catalyst lowers the activation energy of both the forward and reverse processes during the hydrogenation process.
The cis double bonds in vegetable oils can hydrogenate and dehydrogenate.

There are either cis or trans stereochemistry with the double bonds.

The white, creamy product has fewer double bonds overall, but some may be in positions or stereochemical configurations that are not found in nature.

The FDA recommends a nationwide ban on trans fats and requires them to be listed on food labels.

More and more national and local governments are banning the use of partially hydrogenated vegetable oils in food.

Give an equation for the complete hydrogenation of trilinolein.

Predict the melting points for the starting material and the product by naming it.

Diesel engines can run on cooking oil if it's warm, but it's not enough to start a cold diesel engine.

A base-catalyzed transesterification uses alcohol and NaOH as the catalyst and converts fats and oils to the three individual fatty acids.
The methyl esters are more volatile than the original triglyceride and work well in diesel engines.

There are environmental advantages to using biodiesel over conventional diesel fuel.

It converts waste cooking oil into a useful product and reduces the amount of waste going into landfills.

The cycle of production and use of biodiesel might not add as much carbon dioxide to the atmosphere as the burning of petroleum-based diesel fuels because of the recent synthesis of atmospheric carbon dioxide.

Several countries have enacted laws mandating the use of biodiesel in blended diesel fuels, hoping to slow the increase in atmospheric carbon dioxide that is thought to contribute to global warming.

Simple solutions are rarely used for complex problems.
The supply of waste fats and oils isn't enough to meet the requirements of these laws.
Food-grade oils sell for several times the price of diesel fuel, so it's not economically sound to convert new food-grade fats and oils.
Fuel suppliers have turned to the world market for vegetable oils, encouraging the clearing of rain forests in tropical countries to produce palm oil and soybean oil for transesterification to biodiesel.

Give an equation for the complete transesterification of triolein using an excess of methanol as the alcohol and sodium hydroxide as the catalyst.

The process of sphaonification was discovered before 500 b.c., when people found that fat from animals was heated with wood ashes.

The acids in the ashes cause the fat to break down.
The soap is made by boiling animal fat or vegetable oil.
The formation of soap is a result of tristearin, a component of beef fat.

The negatively charged carboxylate end of the molecule has a high electron density.

The carboxylate oxygen atoms are involved in strong hydrogen bonding with water.
The rest of the molecule can't participate in hydrogen bonding with water.

The micelle is a stable particle because the groups are hydrogen-bonded to the surrounding water, and the groups are shielded inside the micelle.

The different affinities of a soap's two ends make it useful for cleaning.

Greasy dirt can't be easily removed by pure water because it's insoluble in water.

A micelle can form around a small grease droplet if it is covered by soap.

The soap molecule has high electron density in the negatively charged head and green in the hydrocarbon tail.

In water, soap forms a cloudy solution of micelles with the heads in contact with water and the tails in the interior.
The water surrounding the micelle has Na+ ion dissolved in it.

The conjugate groups of the soap cover the suspended conjugates in water.

The grease goes with the wash water when it is washed away.

The soap's tendency to leave solu tion in hard water limits its usefulness.

The soap molecule is bound to the free fatty acids in acidic water.

Many areas have household water that has calcium, magnesium, and iron in it.

The carboxylate groups of the soap are shown in the equation.

The reactions of sodium myristate can be shown with the following equations.

The most widely used class of detergents are the salts of sulfonic acids.

The salts of carboxylic acids are not protonated, even in strongly acidic wash water.
sulfonate salts can be used in hard water without forming a scum.

Synthetic detergents have the same regions as soaps.

A alkyl group or aromatic ring is a hydrophobic region.
There are anionic groups, cationic groups, and nonionic groups inphilic regions.

Synthetic detergents may have functional groups.

Gardol is a carboxylate salt and forms a precipitate in hard water.

One of the fatty acids of a triglyceride is replaced by a phosphoric acid group in a phosphoglyceride.

A phosphatidic acid is deprotonated at a neutral pH.

The structure of the phospholipids gives them some interesting properties.

Like soaps, they form micelles and other aggregations with their polar heads on the outside and non polar tails on the inside.

In a bilayer, the heads coat the two surfaces and the tails are protected.

A barrier that restricts the flow of water and dissolved substances can be formed by cell membranes.
Studies show that the two tails of phospholipids occupy the right amount of space to make the strongest bilayers.
The single tails of soaps leave too much space, while the triple tails of triglycerides leave too little space for optimum bilayers.

The polar heads of phosphoglycerides can be exposed to the solution and protected from the hydrocarbons.

A part of the cell is the bilayer.

Steroids are found in plants and animals.

Steroids include hormones, emulsifiers, and components of membranes.
The carbon atoms are numbered beginning with the A ring and ending with the two "angular" groups, and the four rings are designated A, B, C, and D.

Section 3-16B shows that fused ring systems can have either trans or cis stereochemistry at each ring junction.

All three of the ring junctions are trans in the androstane structure shown above.
The trans isomer is quite rigid and flat if you make a model of it.

The cis isomer has two rings that are at a sharp angle to each other.

The three ring junctions are trans in androstane.

The all-trans structure of most steroids results in a stiff, nearly flat molecule.
The A ring has to fold down below the rest of the ring system in some steroids.
Natural steroids are used to trans in the B-C and C-D ring junctions.

The second ring and junction hydrogens arecis.

Steroids may have a cis or trans A-B ring junction.

The other ring junctions are not always trans.

The androstane ring system is the basis of andsterone.

There is a side chain at C17 and a double bond between C5 and C6.

Sex hormones have been studied extensively.

The C19 group must be lost.

In mammals, testosterone is converted to estradiol in the female's ovaries, where the aromatic A ring can be found.

When steroid hormones were first isolated, people thought they couldn't compete with natural steroids.

Steroids are hundreds or thousands of times more potent than natural steroids.

ethynyl estradiol is a synthetic female hormone that is more potent than estra.
Ethynyl estradiol is used in oral contraceptives.

The adrenocortical hormones have either a carbonyl group or a hydroxy group at C11 of the steroid skeleton.

Cortisol is used for the treatment of inflammatory diseases of the skin, joints, and lungs.

Fluocinolone acetonide and beclomethasone are more potent for treating asthma than Cortisol is.

Determine whether each red group is an axis or an equator by drawing each molecule in a stable chair.

They have a carbonyl group on C9.

There are hormones for oral contraceptives.

The market for barbasco collapsed.

The cis double bond between prostaglandins and steroids was found in the 1970s.
The number of double bonds is also given in the name, as shown here for in soybeans, a cheaper and more prostaglandins.

Arachidonic acid is a 20-carbon fatty acid with four cis double bonds.

Lowering the inflammatory response is one of the functions of aspirin.

Prostaglandins are difficult to remove from animal tissues because of their small concentrations.

The process of making them is long and difficult, and only a small amount of product is obtained.
This coral prostaglandin is a starting material for efficient prostaglandins.

This compound can be used to grow plants.

They have pleasant tastes and are widely used as flavor to medically useful prostaglandins.

Hundreds of essential oils were used as perfumes, flavorings, and medicines.

Prostaglandins oil of turpentine has a C:H ratio of 5:8 and many other essential oils have similar ratios.

Otto Wallach, a German chemist, determined the structures of several terpenes in the 19th century.

The isoprene unit is used for the treatment of wounds.

The essential oils of fragrant plants are the source of many terpenes.

The isoprene molecule and isoprene unit have heads and tails.

Myrcene can be divided into two isoprene units, with the head of one unit bonding to the tail of the other.

There are three isoprene units in b@selinene.

The head-to-tail arrangement is more difficult to see because of the additional bonds used to form the rings.

carboxyl groups and hydroxy groups are found in many terpenes.

A terpene aldehyde, a terpene alcohol, a terpene ketone, and a terpene acid are shown.

They are brightly colored because of their extended system of double bonds.

Carotenes help to give tree leaves their fiery colors in autumn, and they are responsible for the pigmentation of carrots, tomatoes, and squash.
It can be divided into two diterpenes.

Cholesterol has lost three carbon atoms from the original six isoprene units of squalene.

There is a carbon atom between rings C and D.

Carotenes are thought to be the biological precursors of retinol.

Each of the diterpene fragments can be converted to retinol if a molecule of b@carotene is split in half at the tail-to-tail linkage.

Natural products that do not have carbon skeletons composed exclusively of C5 isoprene units are derived from terpenes.

They could have been altered by loss of carbon atoms or introduction of additional carbon atoms.
Some of the isoprenoid carbon atoms have been lost inCholesterol is an example of a terpenoid that has lost some of the isoprenoid carbon atoms.

cholesterol is a triterpenoid formed from six isoprene units with loss of three carbon atoms.

There are six isoprene units with the exception of one tail-to-tail linkage.
squalene is believed to be the triterpene precursor of cholesterol.
An acid-catalyzed cyclization of squalene can give an intermediate that is later converted to cholesterol with loss of three carbon atoms.

A mixture of ethyl and methyl acids are produced from fats and oils.

This mixture can be used in diesel engines.

A compound is an emulsifying agent.

A few of the common classes of synthetic detergents are alkylbenzenesulfonate salts, alkyl sulfate salts, alkylammonium salts, and nonionic detergents.

The formation of an emulsion is promoted.

A mixture of two liquids dispersed in small droplets.

There is a solid at room temperature.

The numbers of carbon atoms in most naturally occurring fatty acids are between 12 and 20.

The water has acids or ion that react with soaps to form precipitates.

It was attracted to the water.

The two surfaces of a structure are formed by an aggregation of phosphoglycerides with the hydrophilic heads.

Substances can be taken from cells and tissues.

Cholesterols that are easy to make are usually simpler to make.

It is not easy to lysosomal to simpler constituents.

A group of compounds suspended in a solvent, usually water.

The heads of the molecule are in contact with the solvent, and the tails are in the cluster.
There is a chance that the micelle does not contain an oil droplet.

There is a liquid at room temperature.

The three hydroxy groups are esterified by two fatty acids and a phosphoric acid derivative.

There is a variety of glycerol esterified by two fatty acids and one free phosphoric acid group.

A variety of compounds with the same name are in the group.

A variety of conjugates with a group of acids called the phosphoric acid group.

There are at least one or more groups derived from phosphoric acid.

There are multiple carbon-carbon double bonds.

Usually applied to fish oils and vegetable oils that contain double bonds.

A class of biochemical regulators consists of a 20-carbon carboxylic acid with a cyclone ring.

It was used to describe the process of making soap.

There are few or no carbon-carbon double bonds in glycerol.

Saturated fats are found in butter, lard, and tallow.

The compound is based on the ring system.

A family of compounds composed of two or more 5-carbon isoprene units.

A family of compounds with altered or rearranged carbon skeletons.

The trans isomers of fatty acids are unnatural.

Trans fats are formed in the partial hydrogenation of vegetable oils to make margarine and vegetable shortening.

Each skill is followed by problem numbers.

Determine the number of carbon atoms in the isoprene units.

Explain how detergents and soaps work.

Predict the products from the reaction of oleic acid.

How would you convert linoleic acid to the following derivatives?

The general classification of each compound is given.

The structure of a phospholipid needs to be drawn.

Draw the products that would come from it.

Show how you would make a compound from tristearin.

A triglyceride can be active if it has more than one type of fat.

One equivalent of myristic acid and two equivalents of oleic acid are contained in the structure of an optically active triglyceride.

Draw the structure of a triglyceride with the same composition.

One equivalent of stearic acid and two equivalents of oleic acid are contained in the structure of an optically active triglyceride.

When this triglyceride reacts with the following reagents, draw the products expected.
Predict whether the products will be active.

Predict the products formed when a-pinene reacts with some reagents.

The previous fat replacements did not give as good a sensation in the mouth and were not suitable for frying.

The glycerol molecule of a fat is replaced by sucrose with Olestra(r).
In Olestra, the sucrose molecule has six, seven, or eight hydroxy groups.
The vegetable oils that produce the fatty acids are soybean, corn, palm, coconut, and cottonseed oils.
The fat-like molecule doesn't pass through the walls of the sphinx and the sphinx can't get close to the center to bind it to their active sites.
It provides zero calories when Olestra passes through the system.
Draw an Olestra molecule using any of the fatty acids found in vegetable oils.

The structure of bile's major component, cholic acid, is shown.

Draw the structure of cholic acid, showing the rings in their chair CH3 H conformations, and label each methyl group and hydroxy group.

Cholic acid is produced in bile as an amide.

Explain why it is a good emulsifying agent.

Circle the isoprene units in the following terpenes and label them as monoterpene, sesquiterpene, or diterpene.

Pure stearic acid can be given by hydrogenation.

Dodecanoic acid and adipic acid are the only organic products when the acid is treated with warm potassium permanganate.
The spectrum shows the absorption of vinyl protons by the constants of 7 and 10.
Show how your structure is consistent with the observations.

Two lactones are shown.

Circle the isoprene units if that is the case.

In plants that need fire to reproduce, the main ingredient in burning plants is catnip.

There are five compounds found in Vapo-Rub.

linolenic acid undergoes oxidation in the air.

Saturated fats are preferred for deep fat frying because of the oxidation reaction.

A diradical is a molecule of oxygen.

There is a plausible mechanism for this reaction.

The oxidation mechanism is interrupted by the addition of BHA and BHT.

Suggestions on how these molecules might work.