A strain of Vibrio cholerae lacking the cholera toxin gene (ctxAB) would be
A. unable to survive outside of the human gut.
B. unable to survive inside the human digestive tract.
C. unable to cause watery diarrhea.
D. unable to adhere to the intestinal epithelium.
E. All of these choices are correct.
Answer: C
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Actinomyces spp., Bifidobacterium spp., and Clostridium spp. can be described as:
a. aerotolerant organisms that can grow in the presence of either reduced or atmos-pheric oxygen but grow best under mi-croaerobic conditions. b. strictly anaerobic organisms that cannot grow in the presence of either reduced or atmospheric oxygen but grow only under anaerobic conditions. c. aerotolerant organisms that can grow in the presence of either reduced or atmos-pheric oxygen but grow best under anae-robic conditions. d. facultatively anaerobic organisms that grow in the presence or absence of at-mospheric oxygen.
A substrate is another term for a(n) ____
a. enzyme b. product c. reactant d. active site e. cofactors
The ENCODE project seeks to
A. sequence the genomes of all animals. B. identify the functional elements of the human genome. C. identify the coding sequences of human DNA. D. sequence the DNA of all organisms. E. identify the proteins encoded by the human genome.
Genetics studies of human populations have revealed that
A) it is nearly impossible to determine the relatedness of human populations. B) Homo sapiens probably did not evolve from primates. C) humans have very little genetic variation compared to other mammals. D) all humans are virtually identical. E) human populations vary tremendously at the level of DNA sequences.