9) According to the negative-pleiotropy model of aging, why are alleles that cau
ID: 145078 • Letter: 9
Question
9) According to the negative-pleiotropy model of aging, why are alleles that cause Altzheimer’s disease, via a failure of the amyloid beta protein, relatively common?
A) We are selected by mechanisms that weed out the old and the sick among us
B) Because the allele arose by mutation
C) Because Altzheimers inevatibly occurs in postreproductive individuals, and is not subject to natural selection.
D) Not true, the amyloid beta protein has nothing to do with Altzheimers.
E) Not true, Altzhemer’s disease is very rare.
14) Which of the following statements, about ectoparasites of obligate endothermic homeotherms, that stay on a single host, are generally true?
a) They generally cannot tolerate cold temperatures, since they exploit the homeostatic abilities of their hosts.
b) They frequently have reduced heads and sense organs.
c) They frequently have grasping hooks or claws, since staying on a host is essential for maintaining homeostasis.
d) All of the above
e) A and C
15) As a steelhead trout acclimates from a temperature of 20oC estuary to 5 oC
mountain stream, which of the following statements would you expect to be true?
a) The maximum temperature it can tolerate will increase.
b)The lipid composition of its cells will change, favoring more unsaturated hydrocarbons in its cell membranes.
c)The trout will be able to survive, and perhaps even reproduce, at temperatures that might have killed it before.
d)The lipid concentration of its cells will change, favoring more saturated hydrocarbons in its cell membrane.
e) B and C
Explanation / Answer
9]B) Because the allele arose by mutation
14] A and C
15]The lipid concentration of its cells will change, favoring more saturated hydrocarbons in its cell membrane.
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