biochemistry carbohydrates

carbohydrates

are polyhydroxy aldehydes or ketones

main functions of carbohydrates in our body ?

1) cell membrane components
2)main source of energy by 75%
3) energy store glycogen in liver and muscles but muscles more
4) included in genetic materials

why body not use lipids as major energy source instead of CHO ?

Because carbohydrates are easily available as respiratory substrate but lipids are richer source of energy

why the cell excess glucose as glycogen ?

because of its high osmotic pressure. the glucose exerts inside the cell causing the entry of water in cell by endomosis

what is the product of aldose cyclization of glucose ?

the nucleophilic alcohol attacks the electrophilic carbonyl carbon allowing the formation of a hemiacetal

pentoses examples:

1) ribose
2)ribulose

hexoses example :

1) glucose
2) galactose
3) mannose
4) fructose

insomers:

compounds the have the same chemical formula but different structures

glucose and galactose are

C-4 epimers

glucose and mannose

C-2

oxidation products:

1) uronic acid
2) aldonic acid
3) saccharic acid

glucose and fructose are isomers but not

epimers

uronic acid:

oxidation of aldose at primary alcohol (COOH) betb2a ta7t

aldonic acid:

oxidation of aldose at carbonyl carbon (COOH) FO2

saccharic acid

oxidation of aldose at both aldehyde and terminal carbons

Reducing and nonreducing sugars

1)all mono are reducing
2) all di are reducing except sucrose
3) olgi and poly are non

Disacharide

1) sweet tasting
2) water soluble

glucose + glucose

= maltose

glucose + fuctose

sucrose

glucose + galactose

= lactose

condensation reaction

occurs when two mono units are joints to form dissacharide

hydrolysis

breaking reaction

what kind of bond is glycosidic linkage ?

polar covelant bond

maltose

malt sugar

sucrose

table sugar

lactose

milk sugar