Basic Molecular Genetic Mechanism

ion concentration

When the ________ is low, this shielding is decreased, increasing the repulsive forces between the strands and reducing the Tm.

RNA polymerases

Transcription of genes by ________ containing o54 is regulated by activators whose binding sites in DNA, referred to as enhancers.

catabolite activator protein

Transcription of the lac operon under different conditions are controlled by lac repressor and ________ (CAP)

Small proteins

________ of 100- 200 amino acids are therefore made in a minute or less.

chemical linkage

The ________ between adjacent nucleotides, commonly called a** phosphodiester bond** actually consists of two phosphodiester bonds, one on the 5 sides of the phosphate and another on the 3 side.

extracellular adhesive protein

Fibronectin**, a multidomain ________ found in mammals, provides a good example of alternative splicing.

protein domains

Individual repeated ________ often are encoded by one exon or a small number of exons that code for identical or nearly identical amino** acid sequences**

Base pairing

________ is apparent between the tRNAs in the A and P sites with their respective codons in mRNA.

gene expression

Proteins are largely responsible for regulating ________, the entire process whereby the information encoded in DNA is decoded into the proteins that characterize various cell types.

Nucleic Acid Strand

# # A(n) ________ Is a Linear Polymer with End- to- End Directionality.

genetic information

Carries the ________ transcribed from DNA in the form of a series of three- nucleotide sequences- called** codons** (each specifies a particular amino acid.

Denaturation

________ and renaturation of DNA are the basis of** nucleic acid hybridization**

E coli

In ________, about half the genes are clustered into operons each of which encodes enzymes involved in a particular metabolic pathway or proteins that interact to form one multisubunit protein.

eukaryotic protein

The** ________- synthesizing** machinery begins translation of most cellular mRNAs within about 100 nucleotides of the 5 capped end as just described.

Watson Crick

The four stems are short double helices stabilized by ________ base pairing; three of the four stems have loops containing seven or eight bases at their ends.

Deoxyribonucleic acid

________ (DNA)** contains all the information required to build the cells and tissues of an organism.

single coat

In some viruses, multiple copies of a(n) ________ protein form a helical structure that encloses and protects the viral RNA or DNA.

7 methylguanylate

A(n) ________ that is connected to the terminal nucleotide of the RNA by an unusual 5, 5 triphosphate linkage.

single eukaryotic mRNA

The translation of a(n) ________** molecule to yield a typical- sized protein takes 30- 60 seconds.

Cells

________ can regulate protein synthesis by phosphorylating a serine residue on the eIF2 bound to GDP.

Eukaryotic

________ proteins** that participate in DNA replication has come largely from studies with small viral DNAs, particularly SV40 DNA, the circular genome of a small virus that infects monkeys.

arrangement of coat

The number and ________ proteins in** icosahedral**, or** quasi- spherical**, viruses differ somewhat depending on their size.

RNA

________ viruses**, which usually replicate in the host- cell cytoplasm, have a(n) ________ genome, and DNA viruses, which commonly replicate in the host- cell nucleus, have a DNA genome.

Polynucleotides

________ can twist and fold into three- dimensional conformations stabilized by noncovalent bonds.

inducer

A small molecule (or molecules), called an** ________**, binds to the repressor.

electron micrographs

Structures that are referred to as** polyribosomes** (or polysomes) were seen to be circular in ________ of some tissues.

Simultaneous translation

________ of an mRNA by multiple ribosomes is readily observable in electron micrographs and by sedimentation analysis, revealing mRNA attached to multiple ribosomes bearing nascent growing polypeptide chains.

Adsorption

________**- Virion interacts with a host cell by binding multiple copies of capsid protein to specific receptors on the cell surface.

DNA

Information stored in ________ is arranged in hereditary units, now known as genes, that control identifiable traits of an organism.

few bacterial mRNAs

In a(n) ________, GUG is used as the initiator codon, and CUG occasionally is used as an initiator codon for methionine in eukaryotes.

Adenine

________ rarely is found in the anticodon wobble position, many tRNAs in plants and animals contain inosine (I), a deaminated product of ________, at this position.

Downstream

________ denotes the direction in which a template DNA strand is transcribed (or mRNA translated); a(n) ________ sequence is toward the 3 ends relative to the start site, considering the DNA strand with the same polarity as the transcribed RNA.

activator proteins

Specific ________, such as CAP in the lac operon, also control transcription of some but not all bacterial genes.

variety of conformations

Most cellular RNAs are single- stranded and exhibit a(n) ________.

DNA of viruses

Introns are present in the ________ that infect eukaryotic cells.

animal

For ________ and plant viruses, viral proteins also enter the host cell.

transcription

Stimulates ________ from the promoter of the glnA gene.

enzyme

The ________ binds to DNA at random sites and breaks a phosphodiester bond in one strand.

lytic replication

Most plant and animal viruses with an RNA genome do not require nuclear functions for ________.

natural DNA

In ________, A always hydrogen bonds with T and G with C, forming A·T and G·C base pairs.

Eukaryotic eRF1

________, whose shape is similar to that of tRNAs, apparently acts by binding to the ribosomal A site and recognizing stop codons directly.

Inosine

________ can form nonstandard base pairs with A, C, and U.

outside of B

On the ________- form DNA, the spaces between the intertwined strands form two helical grooves of different widths described as the major groove and the minor groove.

protein synthesis

In the process of transcription, the information stored in DNA is copied into** ribonucleic acid** (RNA), which has three distinct roles in ________.

GDP

The** phosphorylated** complex is unable to exchange the bound ________ for GTP and can not bind Met- tRNAiMet, inhibiting protein synthesis.

eukaryotic cells

Synthesis of all polypeptide chains in prokaryotic and ________ begins with the** amino acid methionine**

peptide bond synthesis

Following ________, the ribosome is translocated along the mRNA at a distance equal to one codon.

Transcription initiation

________** is considered complete when the first two ribonucleotides of an RNA chain are linked by a** phosphodiester bond**

growth results

Because chain ________ from the formation of a phosphodiester bond between the 3 oxygen of a growing strand and the phosphate of a dNTP.

operons

Transcription of ________, as well as of isolated genes, is controlled by an interplay between RNA polymerase and specific repressor and activator proteins.