This preview shows page 1. Sign up to view the full content.
Unformatted text preview: ce.
51. A. This answer is arrived at by process of elimination. B is incorrect because one would
expect that an enzyme that breaks down muscle components would increase in a
degenerative disease. C is incorrect because the passage states that heart muscle fibers are
affected, most likely affecting an EKG. D is incorrect because DMD causes a disruption in
dystrophin production, so decreased levels of dystophin are expected. Therefore, answer A is
52. A. There are two things that you need to remember to determine the sequence of DNA that is
complementary to the segment of DNA given in the passage. The first is that DNA strands
are situated antiparallel to one another in a DNA helix, meaning that the 3’ end of one strand
is paired with the 5’ end of the other strand. The next important point is that the DNA there is
complementary pairing of nitrogenous bases; that is, adenine always pairs with thymine, and
cytosine always pairs with guanine. Taking this information, we can start from the 3’ end of
the given strand, which will correspond to the 5’ end of the complementary strand, and match
up the bases with their complements. Therefore, the complementary DNA strand will be
TCGCTCTATGGC in the 5’ to 3’ direction. So, choice A is the right answer. Choice C is
wrong because it has the wrong polarity but the right sequence. Choices B and D are wrong
because they both contain uracil, which is only found in RNA.
53. D. Epistasis is the phenomenon of one gene modifying another’s expression. Polygenes are
the genes involved in that modification. A dilution gene would be an example of a modifying
gene. However, pleiotropy occurs when a single gene influences multiple phenotypic traits
(such as a particular protein found in multiple structures). Page 6 of 12 54. A. Coat length is an autosomal trait with short being dominant to long. Black/red color is an
X-linked trait expressed through X-inactivation. The homozygous short-haired, black male is
of genetype LLXbY and the long-haired, red female is of genotype llXrXr. F1 progeny would
be all heterogygous short-hai...
View Full Document
- Spring '11