What is a regulatory protein for a gene? It binds to specific DNA sequences with high affinity and plays a predominant role in determining if a genome segment is transcribed or not.
a) the terminator
b) the promotor
c) the structural genes
d) the repressor
e) the operator
Ans: d) the repressor
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After growth in tissue culture, the infected cells lyse and the virus may be harvested from
A. the lysate, the liquid supernatant after centrifugation. B. the remainder. C. the quantal layer. D. the monolayer.
In a population of rabbits, those able to outrun predators will survive to reproduce, eventually leading to a population
of faster rabbits. This is an example of ____ selection.
a. directional b. stabilizing c. disruptive d. mutational e. restricted
The classic Hershey and Chase (1952 ) experiment that offered evidence in support of DNA being the genetic material in bacteriophages made use of which of the following labeled component(s)?
A) tritium B) hydrogen C) nitrogen and oxygen D) phosphorus and sulfur E) None of the answers listed is correct.
Gangrene is often caused by anaerobic bacteria deep in tissues that lack adequate blood flow and adequate oxygen supply. Many times, gangrene can be treated by putting the patient into a hyperbaric chamber. Which statement best describes why this type of therapy is effective?
A) The increased pressure drives nitrogen into the system and nitrogen gas poisons the bacteria. B) The increased pressure drives more oxygen into the bloodstream and, therefore, anaerobic bacteria cannot survive in the presence of oxygen. C) The increased pressure creates a higher pressure in the capillaries of the tissue and drives the toxin produced by the bacteria into the bloodstream, where it is diluted. D) The increased pressure destroys the cell wall of the bacteria. E) When the patient is brought back to normal atmospheric pressure, carbon dioxide comes out of solution at high concentrations, which poisons the bacteria.