BI203 Midterm 2 Wrong Answers Review

Question 1

Unrepaired pyrimidine dimers in humans may lead to melanoma such as Xeroderma pigmentosum, a genetic disease in which the ___ ___ ___ is lacking, resulting in skin discoloration and multiple tumors following exposure to UV light.

Answer 1

nucleotide excision repair

Question 2

What pair of nitrogenous bases might form a dimer in DNA when exposed to UV radiation?

Answer 2

cytosine - cytosine

Question 3

Q: How would mismatch repair fix the incorrect base pair below during DNA replication?

A: The adenine would be replaced by cytosine; ___ only.

Answer 3

prokaryotes

Question 4

___ ___ during the initiation of translation in eukaryotes, allows the small ribosome subunit to scan the codon from the 5’ cap, until it reaches the AUG start codon.

Answer 4

ATP hydrolysis

Question 5

Q: Treatment of cells in culture with an inhibitor of reverse transcriptase activity would affect which of the following?

A: ___ of the 3’ ends of telomeres during DNA replication

Answer 5

extension

Question 6

Termination of translation and release of the polypeptide chain occurs when a protein release factor binds to the ___ ___.

Answer 6

termination codon

Question 7

The ENCODE project revealed that as much as 75% of the human genome is ___.

Answer 7

transcribed

Question 8

The ENCODE project revealed that as much as ___% of the human genome is transcribed.

Answer 8

75%

Question 9

The endogenous ___ sequences are replaced with ___ versions, leading to the dog breeds with short legs and abnormal expression of Fgf4.

Answer 9

regulatory, mutated

Question 10

The ___ is the large multisubunit complex that links the general transcription factors to the gene-specific transcription factors.

Answer 10

mediator

Question 11

Catabolite repression in E. coli is reversed by ___ binding to catabolite activator protein.

Answer 11

cAMP

Question 12

Enhancer elements are generally distance-___ and orientation-___, wheras basal promoter elements such as the TATAA box are BOTH distance and orientation dependent with respect to the transcription start site.

Answer 12

INDEPENDENT

Question 13

Chromatin-remodeling complexes provide access to the DNA molecule by using the energy of ___ ___ to ___ nucleosomes.

Answer 13

ATP hydrolysis, move

Question 14

RNA Polymerase synthesizes in 5’ to 3’ direction, BUT the ANTISTRAND is OPPOSITE!!! (___ to ___) Like EVERY Replication/Transcription STRAND!

Answer 14

3’ to 5’

Question 15

If DNA synthesis proceeded 3’ to 5’ and an incorrect base was added to a growing chain, then the excision of the mismatched terminal 5’ nucleotide during proofreading by DNA polymerase would prevent further incorporation of free nucleotides,

because the ___ ___ of the new ___ ___ has now been excised.

Answer 15

triphosphate group of the new terminal nucleotide

Question 16

Q: Suppose that a single protein in two different cell lines is significantly overexpressed in one of them. The proteins are identical, yet Northern blot analysis has demonstrated that the mRNA for the protein in the overexpressing cell line is about 200 base pairs shorter. Subsequent reverse transcriptase PCR has revealed that the truncation occurs in the 3’ untranslated region. What best explains the overexpression of the protein?

A: A translational repressor recognized a specific sequence in the ___ ___.

Answer 16

3’ UTR

Question 17

Conformation changes in DNA polymerase, 3’ to 5’ exonuclease activity of DNA polymerase, AND the Requirement of a primer for DNA synthesis by DNA polymerase, all

account for the ___ replication error frequency than would be predicted on the basis of complementary base pairing.

Answer 17

lower

Question 18

cAMP activates cAMP-dependent protein kinase by binding the regulatory subunits and inducing the release of the ___ ___.

Answer 18

catalytic subunits