E. coli can synthesize the amino acid threonine or absorb it from the environment. In the thr operon, the repressor is active when it is bound to threonine. If an E. coli bacterium is in an environment where threonine is absent, will transcription of
threonine synthesis genes take place? Why or why not?
A) yes, because threonine will not be bound to the repressor, so the repressor will be inactive
B) no, because threonine will not be bound to the repressor, so the repressor will be inactive
C) yes, because threonine will not be bound to the repressor, so the repressor will be active
D) no, because threonine will not be bound to the repressor, so the repressor will be active
Answer: A
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Propionibacterium
A. produces propionic acid. B. produces lactic acid. C. is responsible for the holes in Swiss cheese. D. requires aerobic environments. E. produces propionic acid AND is responsible for the holes in Swiss cheese.
Which statement BEST describes the role and importance of mobile genetic elements in genomes?
A) Mobile genetic elements almost always have either neutral or deleterious consequences for their host. B) Mobile genetic elements are largely beneficial to hosts because they introduce new phenotypic variation into a population via transposition and/or duplication of important genes. C) Mobile genetic elements can have deleterious, neutral, OR beneficial consequences for the host organism, and all three kinds of outcomes are common. D) Mobile genetic elements are especially important for plant genomes such as the tomato, but they are not present in most animal genomes.
During insect complete metamorphosis, a larva forms a ________ before becoming an adult
Fill in the blank(s) with correct word
A potential shortcoming of the probit/logit models is that to get consistent estimates of the parameters:
A. coefficient estimates cannot be evaluated against alternative hypotheses. B. moment conditions are required for each parameter to be estimated. C. the unobservables must be distributed via the standard normal (for probit) and logistically (for the logit). D. the determining function must be linear.