An example of a purine is
A) thymine.
B) guanine.
C) acridine.
D) cytosine.
E) uracil.
B) guanine.
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Mice lacking the ability to make caspase-9 die as the result of numerous defects. During the necropsy (animal autopsy) of the animal you note that the brains of these mice are
A) unregulated growth of the nerve cells. B) lack of apoptosis of some cells. C) overstimulation of G-protein-mediated transduction. D) overproduction of the Etr1 receptor protein. E) all of the above
Which of the following is a reasonable explanation for why unsaturated fatty acids help keep a
membrane more fluid at lower temperatures?
a. The double bonds form a kink in the fatty acid tail, forcing adjacent phospholipids to be spaced further apart. b. Unsaturated fatty acids have a higher cholesterol content. c. Unsaturated fatty acids permit more water in the interior of the membrane. d. The double bonds block interaction among the hydrophilic head groups of the lipids. e. The double bonds result in a shorter fatty acid tail.
Calcitonin is produced by the ____ and is important for the uptake of ____ by bones
a. anterior pituitary; calcium b. posterior pituitary; phosphorus c. thymus; calcium d. thyroid; calcium e. hypothalamus; phosphorus
In correct chronological order, the three phases of the human uterine cycle are _____
A) follicular ? luteal ? secretory B) menstrual ? proliferative ? secretory C) follicular ? ovulation ? luteal D) proliferative ? luteal ? ovulation