Final: Biochem Genetics & Cell Cycle End of Chapter Questions Flashcards
A nt sequence 5’-TCCGAT-3’ within human genomic DNA underwent spontaneous mutation resulting in nt sub, producing 5’-TTCGAT-3’. Which one of the following chem rxns could account for the nt sub above?
B. deamination of a pyrimidine
Which of the following characteristics of nucleosomes is important for their ability to package genomic DNA into chromatin?
A. histone constituents of nucleosomes contain a relatively high proportion of lysine and arginine amino acids.
which of the following observations is evidence for semiconservative DNA replication?
C. After DNA synthesis, each daughter molecule contains one parental strand and one new strand
The following DNA sequence is the template for synthesis of newly transcribed RNA: 5’-GGGAAAT-3’. Which of the following sequences represents the RNA synthesized from the template?
A. 5’-AUUUCCC-3’
The anticancer drug cytarabine can be metabolically activated into the compound shown below. Which of the following enzymes is inhibited by this compound?
A. DNA polymerase delta
One mechanism of potential mutation is the insertion of an incorrect nt by DNA pol delta and epsilon into the newly synthesized DNA molecule. Which of the following enzymes, present at the replication fork, repairs nt disincorporation by DNA pol delta during DNA synthesis?
D. DNA polymerase delta
The PEPCK-C gene is transcribed in the liver under normal conditions, and its transcription is induced significantly by glucocorticoids. It was reported in the literature that a nt substitution, at a position outside the protein coding region of the PEPCK-C gene resulted in consistently elevated levels of PEPCK-C transcription that were only increased slightly by glucocorticoid treatment. Which of the following regulatory elements is most likely the site of this mutation?
C. silencer element
This was the question thrown out on the last test.
p16 is a member of the INK family of CDK inhibitor proteins (CIP). It functions by binding to CDK4 and CDK6. What effect does the action of p16 have on the cell cycle?
C. p16 blocks passage of cell cycle thru restriction pt in late G1
Strain of bacteria resistant to antibiotic was isolated in hospital lab. Biochem analysis show treatment of sensitive strain w/antibiotic blocks bacterial RNA synthesis, whereas resistant strain, RNA synthesis was unaffected. The resistant strain is unaffected by which of the following drugs?
C. Rifampcin
What effect does damage to DNA have on p53 protein?
B. stabilizes p53; DNA damage triggers phosphorylation and release of p53 from ubiquitin ligase
Which event is characteristic of intrinsic and extrinsic apoptosis?
D. activation of caspases 3, 6, and 7
How do genetic mutations in proto-oncogenes contribute to cancer?
A. They alter the structure or amount of gene’s protein product
Which of the DNA sequences would have greatest thermal stability?
E. CCCGGGA; greatest # G-C pairs
Valproic acid is clinically used to treat seizures. Biochemically, it is an inhibitor of histone deactylases. Treating cells with valproic acid will likely alter the charge of which of the following amino acids in histones?
E. Lysine
Cells from pt that cannot produce GlcNAc phosphotransferase (phosphorylates mannose on asparagine-linked oligosaccharide chains) would be unable to transport newly synthesized glycoporteins to which of the following locations?
B. Lysosomes
The DNA translocation generating the Philadelphia chromosome involves which proto-oncogene and is diagnostic for which disease?
D. ABL tyrosine kinase, chronic myelogenous leukemia
During the elongation phase of prokaryotic translation, for each amino acid added to the growing peptide chain, 2 FTP molecules are hydrolyzed to GDP. Which of the following aspects of ribosome function requires hydrolysis of one GTP?
B. Aminoacyl-tRNA delivery to A site
on last test
The mRNA sequence 5’-GCG ACG UCC-3’, is being translated by a ribosome. Which of the following sequences represents anticodons of aminoacyl-tRNAs that used (in order) during translation?
D. 5’-CGC, CGU, GGA-3’
Which of the following antibiotics will inhibit cytoplasmic protein synthesis in both prokaryotic and eukaryotic organisms?
E. Puromycin
You are cloning BamHI-cut genomic DNA into the plasmid vector pBR322, which has both ampicillin resistance gene and a tetracycline resistance gene. If the inserts are ligated into the BamH1 site in the tetracycline resistance gene vector, the entire population of transformed bacteria should first be grown on
B. media containing ampicillin
When ribosome reaches stop codon on mRNA, release factors act to change specificity of peptidyl transferase so that the growing peptide chain is transferred to which of the following moieties?
A. Water
on last test
Recombinant human granulocyte-macrophage growth factor (GMCSF), a hematopoietic factor used to treat neutropenia, can be produced in a human cell line engineered to synthesize the protein. Analysis of the glycosulation of recombinant GMCSF (rGMCSF) was performed with PNGase F, an enzyme that catalyzes the complete removal of N-linked oligosaccharides from proteins at the site of attachment. Treatment of rGMCSF released an 8 carb oligosaccharide. Which of the following is true regarding the glycosylated rGMCSF?
D. The oligosaccharide is attached to rGMCSF via an acid amide functional group
IF you are screening a library by nucleic acid sequence homology with a radio labeled DNA probe, how are the bacterial colonies of interest identified?
B. X-ray film
Sometimes the gene responsible for a particular genetic disease has not yet been cloned, so researchers must use a probe that is genetically linked to the gene they wish to follow. If a new restriction fragment length polymorphism (RFLP) is detected using a probe linked to the gene, this result may be interpreted to mean ..?
C. that a mutation has occurred in the gene or in the region flanking the gene
