RNA viruses require their own supply of certain enzymes because A) these enzymes translate viral mRNA into proteins.
B) host cells rapidly destroy the viruses.
C) these enzymes cannot be made in host cells.
D) host cells lack enzymes that can replicate the viral genome.
E) these enzymes penetrate host cell membranes.
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 eukaryotic gene has "sticky ends" produced by the restriction endonucleaseEcoRI. The gene is added to a mixture containingEcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics.
Bacteria containing a plasmid into which the eukaryotic gene has integrated would grow in
A) the ampicillin broth and the nutrient broth.
B) the nutrient broth only.
C) the nutrient broth, the ampicillin broth, and the tetracycline broth.
D) the nutrient broth and the tetracycline broth only.
E) all four types of broth.
The first cloned cat, called Carbon Copy, was a calico, but she looked significantly different from her female parent. Why?
A) Fur color genes in cats are influenced by differential acetylation patterns.
B) The environment, as well as genetics, affects phenotypic variation.
C) The telomeres of the parent's chromosomes were shorter than those of an embryo.
D) Cloned animals have been found to have a higher frequency of transposon activation
E) X inactivation in the embryo is random and produces different patterns.
In the figure, at the arrow marked II, what enzyme(s) are being utilized? A) host cell RNA polymerase
B) host cell DNA polymerase
C) reverse transcriptase
D) viral DNA polymerase
E) host cell DNA and RNA polymerases
aD) host cells lack enzymes that can replicate the viral genome
bE) X inactivation in the embryo is random and produces different patterns
cA) the ampicillin broth and the nutrient broth
dB) host cell DNA polymerase
eD) no AUG in any frame
5 Multiple Choice Questions
B) abnormal regulation due to variant methylation
E) abnormalities of mouse embryos
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
E) Beta galactosidase will be produced
A) a pattern shared among some or all of the samples that indicates gene expression differing from control samples
5 True/False Questions
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. Within the first quarter hour, the researcher sees that the intact RNA is found in the cells. After 3 hours, she is not surprised to find that
A) the double-stranded RNA binds to mRNAs to prevent translation.
B) the double-stranded RNA replicates itself.
C) the RNA is degraded by 5' and 3' exonucleases.
D) Dicer enzyme has reduced it to smaller double-stranded pieces.
E) the double-stranded RNA binds to tRNAs to prevent translation. → D) no AUG in any frame
Which of the following is a protein produced by a regulatory gene? A) operon
E) promoter → E) it is an activator for other genes
In large scale, genome-wide association studies in humans, correlation is sought between
A) large inversions that displace the centromere.
B) lengthy sequences that might be shared by most members of a population.
C) single nucleotide polymorphisms in two or more adjacent genes.
D) single nucleotide polymorphisms found only in persons with a particular disorder.
E) single nucleotide polymorphisms found in families with a particular introns sequence. → D) single nucleotide polymorphisms found only in persons with a particular disorder
To cause a human pandemic, the H5N1 avian flu virus would have to
A) become much more pathogenic.
B) spread to primates such as chimpanzees.
C) arise independently in chickens in North and South America.
D) become capable of human-to-human transmission.
E) develop into a virus with a different host range. → C) include a transgenic rice plant that can help prevent vitamin A deficiency
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. → E) it is an activator for other genes