Review session

Question 1

Chloramphinocol and erythromycin action in tx

Answer 1

inhibit peptydyl transferase

Question 2

what type of enzyme activity does cyclophilin inhibit

Answer 2

peptide prolyl cis-isomerase activity

Question 3

Which of the folowing would NOT typically lead to double-strand breaks in the genome

Answer 3

UV exposure (thymine dimers)

Question 4

Which of these enzymes

Answer 4

skipped over

Question 5

Which of the following statements is true about homologous recombination (HR)?

Answer 5

depends on the availability of the sister chromatid

Question 6

In the Michaelis-Menten description of enzyme kinetics, kcat describes

Answer 6

The number of substrate molecules converted to product at saturating substrate concentrations

Question 7

The mRNA cap serves important roles in splicing, 3’processing, nuclear export, and translation. The first enzymatic step in the addition of the cap to the newly synthesized mRNA is:

Answer 7

Triphosphatase

Question 8

What role does ATP hydrolysis play in chromatin re-modeling by Swi/Snf?

Answer 8

Allows histone-DNA contacts to be broken so the histone can move along the DNA

Question 9

The disease Scurvy results from a deficiency of vitamin C in the diet. This deficiency leads to inadequate modification of which of the following amino acids?

Answer 9

Proline

hydroxylation of proline allows for cross-linking in strains of collagen

Question 10

Which enzyme activity is responsible for synthesizing ribosomal RNAs-18s, 28S, and 5.8S?

Answer 10

RNA pol 1

Question 11

What function does PCNA (proliferating cell nuclear antigen) perform

Answer 11

Acts as a clamp which encircles the DNA and binds the replisome to affect processive synthesis of DNA

Question 12

Which domain contains a Zn finger structure critical for steroid receptor function

Answer 12

DNA binding domain

Question 13

How is synthesis of each Okazaki initiated

Answer 13

DNA primase synthesizes a short oligonucleotide that is extended by the replicative DNA polymerase to form the Okazaki fragment

Question 14

Which of the following is not required for both DNA replication and RNA transcription

Answer 14

Primers

Question 15

Which DNA repair pathway do the MutS and MutL proteins serve?

Answer 15

Mismatch repair

Question 16

In a Southern Blot, what is the purpose of soaking the gel in NaOH?

Answer 16

Denatures the DNA fragments in the gel so the probe can subsequently hybridize to its complementary sequence

Question 17

How do alkylating agents damage DNA?

Answer 17

attack nucleophilic groups on bases, leaving adducts

Question 18

What mismatch repair activity follows the replication fork?

Answer 18

Mismatch DNA repair (i.e., incorrect nucleotide inserted on 3’ terminus)

Question 19

How does tamoxifen antagonize estrogen?

Answer 19

Tamoxifen binds to estrogen receptor and prevents recruitment of HAT co-factors.

Question 20

Chargaff’s rule applies to:

Answer 20

B-form of dup;ex DN A

not single-stranded DNA, rRNA, or mRNA

Question 21

Which protein is a part of the DNA damage checkpoint that facilitates repair following DNA damage?

Answer 21

ATM (Ataxic talentasia mutator)

not DNA ligase, N-glycosidase, or MutY protein

Question 22

How does alpha-amanitin inhibit activity?

Answer 22

Blocks RNA chain elongation by preventing translocation of the RNA pol 2 along the DNA

Question 23

Patients with Cockayne Syndrome, Xeroderma Pigmentosum, and Trichothiodystrophy are all deficient in which of the following DNA repair pathways?

Answer 23

Nucleotide excision repair

vampire syndrome

Question 24

Beta-Amyloid protein production occurs as a result of which enzymatic cleavage sequence?

Answer 24

Beta-secretase followed by gamma-secretase

Question 25

Which of the following amino acids has a polar and -ly charged R group at pH 7?

Answer 25

Glutamate

Question 26

During the initial phase of translation in bacteria, hat guides binding of the mRNA to the 30S subunit of the ribosome?

Answer 26

Pairing of the Shine-Delgarno sequence with the 16S rRNA

Question 27

To which aa do n-linked sugars attach?

Answer 27

asparagine

Question 28

To which aa do o-linked sugars attach?

Answer 28

serine and threonine

Question 29

How does the number of enzymes in a cell affect free energy change in rxns?

Answer 29

It doesn’t. Only lowers activation energy

Question 30

At equilibrium, what is free energy change of a reaction?

Answer 30

zero (already at equilibrium)

Question 31

micro RNAs and snRNAs are examples of

Answer 31

regulatory RNAs