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Unformatted text preview: likely to be homozygous for the deleterious alleles than if out-breeding occurred.
61. C. Transport of sweat electrolytes is accomplished by simple diffusion across a concentration
gradient. Blood plasma has higher electrolyte concentrations than sweat glands. Active
transport is movement of molecules against a concentration gradient. Osmosis involves
movement of water. Page 7 of 12 62. C. Sweating is a response to an increase in body temperature. It is an attempt by the body to
decrease its temperature. Drinking ice water would reduce the core temperature, thus
decreasing the need to sweat.
63. B. This question requires some knowledge of the fate of embryonic tissue. As the disease is
known as ectodermal dysplasia, it is a safe assumption that it affects structures originating
from the ectoderm. From the offered options, only teeth are ectodermal structures and
therefore the most likely to be affected by the dysplasia.
64. B. The extremities of a human are long and thin, maximizing the surface area to volume ratio
of these structures. Since blood vessels loop along the extremity, the counter-current
exchange system can be taken advantage of. Sweating on these extremities accelerates the
heat loss from these large surface area structures, rapidly decreasing the blood temperature
running through them. Answer C is wrong because the entire body is covered in an
ectodermal covering called the skin. D is incorrect because the extremities are actually
located furthest away from the hypothalamus, and it would actually take longer to receive
information from these sources than others in the torso.
65. D. Negative feedback loops involve the product of a reaction inhibiting the reaction itself. It
therefore works to decrease the rate of system, preventing a buildup of product.
66. B. Desert-adapted animals rarely, if ever, sweat. Water is the limiting resource in any desert
and so all animals have mechanisms to minimize water loss. Desert animals have a litany of
other mechanisms to cope with the heat, including being active at n...
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This note was uploaded on 03/23/2011 for the course CHEM 100 taught by Professor Vallis during the Spring '11 term at Dalhousie.
- Spring '11