An operon is:
a. a molecule that can turn genes on and off.
b. an inducer bound to a repressor.
c. a series of regulatory sequences controlling transcription of protein-coding genes.
d. any long sequence of DNA.
e. a promoter, an operator, and a group of linked structural genes.
Answer: e. a promoter, an operator, and a group of linked structural genes.
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As N approaches K for a certain population, which of the following is predicted by the logistic equation?
A) The growth rate will not change. B) The growth rate will approach zero. C) The population will show an Allee effect. D) The population will increase exponentially. E) The carrying capacity of the environment will increase.
Which of the following is not one of the major transport systems of the inner mitochondrial membrane?
A) sodium-potassium pump B) dicarboxylate carriers C) tricarboxylate carriers D) pyruvate carrier cotransport E) ATP-ADP carrier exchange
Molecules called uncouplers allow protons to cross the inner mitochondrial membrane, which decreases the proton gradient potential. Consequently, ATP production in the mitochondria would
A. not change, because protons cross the outer mitochondrial membrane to produce ATP. B. increase, because this would spontaneously establish a proton gradient for powering ATP synthase. C. decrease, because the proton gradient, for powering ATP synthase, would dissipate. D. increase, because this would make more oxygen available in the mitochondrial matrix. E. decrease, because electrons would not be able to move through the electron transport chain.
An isograft has less chance of rejection than a xenograft because
A. new blood vessels need not be formed in the isograft B. the isograft is not composed of living tissue C. the graft composition of the donor and recipient are identical in an isograft D. there are no antigens in an isograft E. it is an allograft