A short segment of a mRNA molecule is shown below. The polypeptide it codes for is also shown:

Assume that a mutation in the DNA occurs so that the fourth base (counting from the 5' end) of the messenger RNA now reads A rather than G. What sequence of amino acids will the mRNA now code for? (You do not need a copy of the genetic code to answer the question.)

A. methionine-valine-leucine-lysine

B. methionine-lysine-leucine-lysine

C. methionine-leucine-leucine-lysine

D. methionine-valine-methionine-lysine

E. methionine-methionine-leucine-lysine

e

The primary structure of a protein is determined by

A. the sequence of amino acids.

B. hydrogen bonds formed between the components of the peptide linkage.

C. a series of helical domains.

D. pleated sheets.

E. covalent bonds formed between fibroin residues.

a

The primary structure of a protein is composed of the sequence of amino acids in that protein.

A. True

B. False

a

Mutant versions of genes which are normally involved in promoting the cell cycle are known as

A. tumor suppressors.

B. proto-oncogenes.

C. oncogenes.

D. malignant genes.

E. attenuators.

c

The genome of humans is remarkably stable, so much so that there are no cancers known to result from genomic instability.

A. True

B. False

b

The gene p53 is called the "guardian of the genome" because it corrects mutations in the spindle apparatus before nondisjunction can occur.

A. True

B. False

b

Proteins are composed of strings of nucleotides connected together by 5'-3' phosphodiester bonds.

A. True

B. False

b

The secondary structure of a protein is dependent on polar interactions among the side chains of the amino acids.

A. True

B. False

b

Sickle-cell anemia is caused by the absence of the alpha chain of hemoglobin.

A. True

B. False

b

The ribonucleic acid components known to exist in eukaryotic ribosomes are the following: 5.8S, 18S, 28S, 5S.

A. True

B. False

a

Which protein class directly controls many of the metabolic reactions within a cell?

A. structural proteins

B. repressor proteins

C. operator proteins

D. enzymes

E. hydrophilic proteins

d

Which of the following are among the major components of prokaryotic ribosomes?

A. 12S rRNA, 5.8S rRNA, and proteins

B. 16S rRNA, 5.8S rRNA, and 28S rRNA

C. 16S rRNA, 5S rRNA, and 23S rRNA

D. lipids and carbohydrates

E. 18S rRNA, 5.8S rRNA, and proteins

c

Any agent which causes damage to DNA is a potential carcinogenic.

A. True

B. False

a

Transcription factors are proteins with at least two functional domains, one that binds to DNA and one that binds to RNA polymerase or to other transcription factors.

A. True

B. False

a

By their experimentation using the Neurospora fungus, Beadle and Tatum were able to propose the far-reaching hypothesis that:

A. Prototrophs will grow only if provided with nutritional supplements.

B.Several different enzymes may be involved in the same step in a biochemical pathway.

C. The role of a specific gene is to produce a specific enzyme.

D. Genetic recombination occurred in Neurospora.

E. More than one codon can specify a given amino acid.

c

Side groups of amino acids are typically grouped under which of the following?

A. polar, nonpolar

B. linear, circular

C. alpha, omega

D. long, short

E. primary, secondary

a

rDNA is that portion of a genome which is involved in the production of ribosomal RNA.

A. True

B. False

a

A retrovirus uses reverse transcriptase to make a DNA copy of RNA.

A. True

B. False

a

Two modular elements which appear as consensus sequences upstream from RNA polymerase II transcription start sites are

A. microsatellites and transposons.

B. rDNA and nucleolar organizers.

C. TATA and CAAT.

D. TTAA and CCTT.

E. enhancers and telomeres.

c

A protein is 300 amino acids long. Which of the following could be the number of nucleotides in the section of DNA that codes for this protein. (Remember, DNA is double stranded.)

A. 3

B. 100

C. 300

D. 500

E. 1800

e

There are two types of retinoblastoma, familial and sporadic. In the familial form, generally one inherits a defective gene from one parent.

A. True

B. False

a

Alternative RNA processing can result in different mRNAs that start with different exons.

A. True

B. False

a

What is the name of the protein that combines with cyclins to exert local control of the cell cycle?

A. cyclin dependent kinase

B. phosphatase

C. ATPase

D. integrase

E. hexokinase

a

Transcription factors are proteins with at least two functional domains, one that binds to DNA and one that binds to RNA polymerase or to other transcription factors.

A. True

B. False

a

Regulation of RNA transport through the nuclear membrane is as common in prokaryotes as in eukaryotes.

A. True

B. False

b

DNA methylation may be a significant mode of genetic regulation in eukaryotes. Methylation refers to

A. altering RNA polymerase activity by methylation.

B. changes in DNA-DNA hydrogen binding.

C. altering translational activity especially of highly methylated tRNAs.

D.alteration of DNA polymerase activity by addition of methyl groups to glycine residues.

E. addition of methyl groups to the cytosine of CG doublets.

e

Which of the following clusters of terms applies when addressing enhancers as elements associated with eukaryotic genetic regulation?

A. cis-acting, variable orientation, variable position

B. trans-acting, fixed position, fixed orientation

C. cis-acting, fixed position, fixed orientation

D. cis-acting, variable position, fixed orientation

E. trans- and cis-acting, variable position

a

The CAAT (CAAT box) sequence appears to be critical to the ability of many eukaryotic promoters to facilitate transcription.

A. True

B. False

a

When a metabolic block occurs in a biochemical pathway, it is common for the substance immediately prior to that block to accumulate in amount.

A. True

B. False

a

Three general mechanisms appear to be involved in the conversion of proto-oncogenes to oncogenes:

A. point mutations, translocations, overexpression.

B. inversions, translocations, methylation.

C. familial, sporadic, phosphorylation.

D. transdetermination, mutation, allosteric interactions.

E. suppression, tabulation, projection.

a

Alternative RNA processing generates different mRNAs which can direct the synthesis of different polypeptides.

A. True

B. False

a

Prokaryotic and eukaryotic ribosomes are structurally and chemically identical.

A. True

B. False

b

There are several checkpoints in the mitotic cell cycle. All occur in the S phase.

A. True

B. False

b