5 Written Questions
5 Matching Questions
- What is the function of reverse transcriptase in retroviruses?
A) It translates viral RNA into proteins.
B) It uses viral RNA as a template for making complementary RNA strands.
C) It uses viral RNA as a template for DNA synthesis.
D) It hydrolyzes the host cell's DNA. E) It converts host cell RNA into viral DNA.
- CML (chronic myelogenous leukemia) results from a translocation between human chromosomes 9 and 22. The resulting chromosome 22 is significantly shorter than usual, and it is known as a Philadelphia (Ph') chromosome. The junction at the site of the translocation causes overexpression of a thymine kinase receptor. A new drug (Gleevec or imatinib) has been found to inhibit the disease if the patient is treated early.
Why would Gleevec most probably cause remission of the disease? A) The drug inhibits the replication of the affected chromosome.
B) It eliminates the Ph' chromosome. C) It removes Ph'-containing progenitor cells.
D) It reverses the chromosomal translocation.
E) The drug inhibits the specific thymine kinase receptor.
- In humans, the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults. This is due to
A) the attachment of methyl groups to cytosine following birth, which changes the type of hemoglobin produced.
B) pseudogenes, which interfere with gene expression in adults.
C) histone proteins changing shape during embryonic development.
D) identical genes that generate many copies of the ribosomes needed for fetal globin production.
E) nonidentical genes that produce different versions of globins during development.
- A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have
A) T4 protein and T4 DNA.
B) a mixture of the DNA and proteins of both phages.
C) T2 protein and T2 DNA.
D) T2 protein and T4 DNA.
E) T4 protein and T2 DNA.
- DNA fragments from a gel are transferred to a nitrocellulose paper during the procedure called Southern blotting. What is the purpose of transferring the DNA from a gel to a nitrocellulose paper?
A) to attach the DNA fragments to a permanent substrate
B) to prepare the DNA for digestion with restriction enzymes
C) to separate the two complementary DNA strands
D) to separate out the PCRs
E) to transfer only the DNA that is of interest
- a E) nonidentical genes that produce different versions of globins during development
- b A) to attach the DNA fragments to a permanent substrate
- c A) T4 protein and T4 DNA
- d C) it uses viral RNA as a template for DNA synthesis
- e E) The drug inhibits the specific thymine kinase receptor.
5 Multiple Choice Questions
- B) increased chromatin condensation
- A) nothing; they self-assemble
- B) interference with viral replication
- B) methylation of the DNA is maintained because methylation enzymes act at DNA sites where one strand is already methylated and thus correctly methylates daughter strands after replication
- B) RNA polymerase must bind to the promoter, and the repressor must be inactive
5 True/False Questions
The host range of a virus is determined by
A) the proteins in the host's cytoplasm.
B) the enzymes carried by the virus. C) whether its nucleic acid is DNA or RNA.
D) the proteins on its surface and that of the host.
E) the enzymes produced by the virus before it infects the cell. → D) rabies
Some viruses can be crystallized and their structures analyzed. One such virus isDesmodium, or yellow mottle virus, which infects beans. This is a member of the tymovirus group and has a single-stranded RNA genome of ~6,300 nucleotides. Its virion is 25—30 nm in diameter, and is made up of 180 copies of a single capsid protein that self-associate to form each capsomere, which has icosahedral symmetry with 20 facets.
In a cell-free system, what other components would you have to provide for this virus to expressits genes?
A) ribosomes, tRNAs, amino acids, and GTP
B) bean cell enzymes
C) RNA nucleotides and GTP
D) RNA nucleotides, RNA polymerase, and GTP
E) ribosomes, tRNAs and amino acids → A) ribosomes, tRNAs, amino acids, and GTP
For a particular microarray assay (DNA chip), cDNA has been made from the mRNAs of a dozen patients' breast tumor biopsies. The researchers will be looking for
A) a pattern shared among some or all of the samples that indicates gene expression differing from control samples.
B) a pattern of fluorescence that indicates which cells are overproliferating.
C) a group of cDNAs that match those in non-breast cancer control samples from the same
D) a group of cDNAs that act differently from those on the rest of the grid.
E) a particular gene that is amplified in all or most of the patient samples. → B) the amino acid acts as a corepressor
Expression of a cloned eukaryotic gene in a bacterial cell involves many challenges. The use of mRNA and reverse transcriptase is part of a strategy to solve the problem of
A) post-translational processing.
B) restriction fragment ligation.
C) nucleic acid hybridization.
D) post-transcriptional processing.
E) electroporation. → D) post-transcriptional processing
Which of the following problems with animal cloning might result in premature death of the clones?
A) use of pluripotent instead of totipotent stem cells
B) abnormal regulation due to variant methylation
C) use of nuclear DNA as well as mtDNA
D) abnormal immune function due to bone marrow dysfunction
E) the indefinite replication of totipotent stem cells → B) abnormal regulation due to variant methylation