5 Written questions
5 Matching questions
- Which of the following is the most probable fate of a newly emerging virus that causes high mortality in its host?
A) The new virus replicates quickly and undergoes rapid adaptation to a series of divergent hosts.
B) The newly emerging virus will die out rather quickly or will mutate to be far less lethal.
C) It is able to spread to a large number of new hosts quickly because the new hosts have no
immunological memory of them.
D) Sporadic outbreaks will be followed almost immediately by a widespread pandemic.
E) A change in environmental conditions such as weather patterns quickly forces the new virus to invade new areas.
- 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 geneticist introduces a transgene into yeast cells and isolates five independent cell lines in which the transgene has integrated into the yeast genome. In four of the lines, the transgene is expressed strongly, but in the fifth there is no expression at all. Of the lines that express the transgene, one is transcribed but not translated. Which of the following is a likely explanation?
A) high histone acetylation
B) no compatible ribosome
C) missing transcription factor
D) no AUG in any frame
E) no promoter
- A researcher introduces double-stranded RNA into a culture of mammalian cells, and can identify its location or that of its smaller subsections experimentally, using a fluorescent probe. Some time later, she finds that the introduced strand separates into single-stranded RNAs, one of which is degraded. What does this enable the remaining strand to do?
A) bind to noncomplementary RNA sequences
B) activate other siRNAs in the cell
C) attach to histones in the chromatin
D) bind to Dicer enzymes to destroy other RNAs
E) bind to complementary regions of target mRNAs
- RNAi methodology uses double-stranded pieces of RNA to trigger a breakdown or blocking of mRNA. For which of the following might it more possibly be useful?
A) to decrease the production from a harmful gain-of-function mutated gene
B) to raise the rate of production of a needed digestive enzyme
C) to raise the concentration of a desired protein
D) to destroy an unwanted allele in a homozygous individual
E) to form a knockout organism that will not pass the deleted sequence to its progeny
- a D) no AUG in any frame
- b A) to decrease the production from a harmful gain-of-function mutated gene
- c A) to attach the DNA fragments to a permanent substrate
- d B) the newly emerging virus will die out rather quickly or will mutate to be far less lethal
- e E) bind to complementary regions of target mRNAs
5 Multiple choice questions
- C) decrease in glucose and increase in cAMP
- B) RNA polymerase must bind to the promoter, and the repressor must be inactive
- D) The BAC carries more DNA, the BAC can carry entire genes and their regulatory elements, and larger BACs are easier to store.
- D) misfolded versions of normal brain protein
- D) antibodies against specific proteins not found in the host membranes
5 True/False questions
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. → D) copies of the herpes virus genome permanently maintained in host nuclei
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. → C) mutation of existing viruses, the spread of existing viruses to new host species, and the spread of existing viruses more widely within their host species
Genetically engineered plants
A) are banned throughout the world.
B) are more difficult to engineer than animals.
C) include a transgenic rice plant that can help prevent vitamin A deficiency.
D) are being rapidly developed, but traditional plant breeding programs are still the only method used to develop new plants.
E) are able to fix nitrogen themselves. → C) allow the expression of many or even all of the genes in the genome to be compared at once
Emerging viruses arise by
A) the spread of existing viruses to new host species.
B) mutation of existing viruses.
C) mutation of existing viruses, the spread of existing viruses to new host species, and the
spread of existing viruses more widely within their host species.
D) the spread of existing viruses more widely within their host species.
E) none of these. → D) the proteins on its surface and that of the host
Poliovirus is a positive-sense RNA virus of the picornavirus group. At its 5' end, the RNA genome has a viral protein (VPg) instead of a 5' cap. This is followed by a nontranslated leader sequence, and then a single long protein coding region (~7,000 nucleotides), followed by a poly-A tail. Observations were made that used radioactive amino acid analogues. Short period use of the radioactive amino acids result in labeling of only very long proteins, while longer periods of labeling result in several different short polypeptides.
What conclusion is most consistent with the results of the radioactive labeling experiment? ]
A) The large radioactive polypeptides are coded by the host, whereas the short ones are
coded for by the virus.
B) The host cell cannot translate viral protein with the amino acid analogues.
C) The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones.
D) Host cell ribosomes only translate the viral code into short polypeptides.
E) The RNA is translated into short polypeptides, which are subsequently assembled into
large ones. → C) The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones