Review session Flashcards
Chloramphinocol and erythromycin action in tx
inhibit peptydyl transferase
what type of enzyme activity does cyclophilin inhibit
peptide prolyl cis-isomerase activity
Which of the folowing would NOT typically lead to double-strand breaks in the genome
UV exposure (thymine dimers)
Which of these enzymes
skipped over
Which of the following statements is true about homologous recombination (HR)?
depends on the availability of the sister chromatid
In the Michaelis-Menten description of enzyme kinetics, kcat describes
The number of substrate molecules converted to product at saturating substrate concentrations
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:
Triphosphatase
What role does ATP hydrolysis play in chromatin re-modeling by Swi/Snf?
Allows histone-DNA contacts to be broken so the histone can move along the DNA
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?
Proline
hydroxylation of proline allows for cross-linking in strains of collagen
Which enzyme activity is responsible for synthesizing ribosomal RNAs-18s, 28S, and 5.8S?
RNA pol 1
What function does PCNA (proliferating cell nuclear antigen) perform
Acts as a clamp which encircles the DNA and binds the replisome to affect processive synthesis of DNA
Which domain contains a Zn finger structure critical for steroid receptor function
DNA binding domain
How is synthesis of each Okazaki initiated
DNA primase synthesizes a short oligonucleotide that is extended by the replicative DNA polymerase to form the Okazaki fragment
Which of the following is not required for both DNA replication and RNA transcription
Primers
Which DNA repair pathway do the MutS and MutL proteins serve?
Mismatch repair
In a Southern Blot, what is the purpose of soaking the gel in NaOH?
Denatures the DNA fragments in the gel so the probe can subsequently hybridize to its complementary sequence
How do alkylating agents damage DNA?
attack nucleophilic groups on bases, leaving adducts
What mismatch repair activity follows the replication fork?
Mismatch DNA repair (i.e., incorrect nucleotide inserted on 3’ terminus)
How does tamoxifen antagonize estrogen?
Tamoxifen binds to estrogen receptor and prevents recruitment of HAT co-factors.
Chargaff’s rule applies to:
B-form of dup;ex DN A
not single-stranded DNA, rRNA, or mRNA
Which protein is a part of the DNA damage checkpoint that facilitates repair following DNA damage?
ATM (Ataxic talentasia mutator)
not DNA ligase, N-glycosidase, or MutY protein
How does alpha-amanitin inhibit activity?
Blocks RNA chain elongation by preventing translocation of the RNA pol 2 along the DNA
Patients with Cockayne Syndrome, Xeroderma Pigmentosum, and Trichothiodystrophy are all deficient in which of the following DNA repair pathways?
Nucleotide excision repair
vampire syndrome
Beta-Amyloid protein production occurs as a result of which enzymatic cleavage sequence?
Beta-secretase followed by gamma-secretase
Which of the following amino acids has a polar and -ly charged R group at pH 7?
Glutamate
During the initial phase of translation in bacteria, hat guides binding of the mRNA to the 30S subunit of the ribosome?
Pairing of the Shine-Delgarno sequence with the 16S rRNA
To which aa do n-linked sugars attach?
asparagine
To which aa do o-linked sugars attach?
serine and threonine
How does the number of enzymes in a cell affect free energy change in rxns?
It doesn’t. Only lowers activation energy
At equilibrium, what is free energy change of a reaction?
zero (already at equilibrium)
micro RNAs and snRNAs are examples of
regulatory RNAs
