5 Written questions
5 Matching questions
- Most human-infecting viruses are maintained in the human population only. However, a zoonosis is a disease that is transmitted from other vertebrates to humans, at least sporadically, without requiring viral mutation. Which of the following is the best example of a zoonosis?
B) hepatitis virus
- Most molecular biologists think that viruses originated from fragments of cellular nucleic acid. Which of the following observations supports this theory?
A) Viruses are enclosed in protein capsids rather than plasma membranes.
B) Viruses contain either DNA or RNA.
C) Viral genomes are usually similar to the genome of the host cell.
D) Viruses can reproduce only inside host cells.
E) Viruses can infect both prokaryotic and eukaryotic cells.
- 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.
- 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.
If this virus has capsomeres with 20 facets, how many proteins form each one?
- Which of the following is characteristic of the product of the p53 gene?
A) It causes cell death via apoptosis.
B) It speeds up the cell cycle.
C) It allows cells to pass on mutations due to DNA damage.
D) It slows down the rate of DNA replication by interfering with the binding of DNA polymerase.
E) It is an activator for other genes.
- a B) ~6
- b C) Viral genomes are usually similar to the genome of the host cell
- c A) a pattern shared among some or all of the samples that indicates gene expression differing from control samples
- d D) rabies
- e E) it is an activator for other genes
5 Multiple choice questions
- E) X inactivation in the embryo is random and produces different patterns
- D) A retrovirus is used to introduce four specific regulatory genes
- C) by adding methyl groups to adenines and cytosines
- D) The BAC carries more DNA, the BAC can carry entire genes and their regulatory elements, and larger BACs are easier to store.
- B) decreased chromatin condensation
5 True/False questions
A) are frequently overexpressed in cancerous cells.
B) do all of the above.
C) can encode proteins that promote DNA repair or cell-cell adhesion.
D) often encode proteins that stimulate the cell cycle.
E) are cancer-causing genes introduced into cells by 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
Which of the following can be effective in preventing the onset of viral infection in humans?
A) applying antiseptics
B) getting vaccinated
C) taking nucleoside analogs that inhibit transcription
D) taking vitamins
E) taking antibiotics → B) getting vaccinated
If glucose is available in the environment of E. coli, the cell responds with a very low concentration of cAMP. When the cAMP increases in concentration, it binds to CAP. Which of the following would you expect to be a measurable effect?
A) decreased binding of the RNA polymerase to sugar metabolism-related promoters
B) decreased concentration of alternative sugars in the cell
C) increased concentrations of sugars such as arabinose in the cell D) decreased concentration of the lac enzymes
E) increased concentration of the trp enzymes → C) increased concentrations of sugars such as arabinose in the cell
The fact that plants can be cloned from somatic cells demonstrates that
A) differentiated cells retain all the genes of the zygote.
B) differentiated cells contain masked mRNA.
C) differentiation does not occur in plants.
D) genes are lost during differentiation.
E) the differentiated state is normally very unstable. → E) bind to the repressor protein and activate it
Plants are more readily manipulated by genetic engineering than are animals because
A) plant genes do not contain introns.
B) genes can be inserted into plant cells by microinjection.
C) a somatic plant cell can often give rise to a complete plant.
D) more vectors are available for transferring recombinant DNA into plant cells.
E) plant cells have larger nuclei. → C) a somatic plant cell can often give rise to a complete plant