290 ❯ STEP 5. Build Your Test-Taking Confidence
10.Which of the following statements about post-
transcriptional modification are incorrect?
A. A poly-A tail is added to the 3′end of the
mRNA.
B. A guanine cap is added to the 5′end of the
mRNA.
C. Introns are removed from the mRNA.
D. Posttranscriptional modification occurs in
the cytoplasm.
11.In a certain pond, there are long-finned fish and
short-finned fish. A horrific summer thunder-
storm leads to the death of a disproportionate
number of long-finned fish to the point where
the relative frequency of the two forms has dras-
tically shifted. This is an example of
A. gene flow.
B. natural selection.
C. genetic drift.
D. stabilizing selection.
12.Which of the following cells is most closely asso-
ciated with phagocytosis?
A. Neutrophils
B. Plasma cells
C. B cells
D. Memory cells
13.Which of the following statements about photo-
synthesis is incorrect?
A. H 2 O is an input to the light-dependent
reactions.
B. CO 2 is an input to the Calvin cycle.
C. Photosystems I and II both play a role in the
cyclic light reactions.
D. O 2 is a product of the light-dependent reactions.
14.If a couple has had three sons and the woman is
pregnant with their fourth child, what is the
probability that child 4 will alsobe male?
A. 1 ⁄ 2
B. 1 ⁄4
C. 1 ⁄ 8
D. 1 ⁄ 16
15.Which of the following is an incorrectstatement
about gel electrophoresis?
A. DNA migrates from positive charge to neg-
ative charge.
B. Smaller DNA travels faster.
C. The DNA migrates only when the current is
running.
D. The longer the current is running, the far-
ther the DNA will travel.
16.You are told that in a population of guinea pigs,
4 percent are black (recessive) and 96 percent are
brown. Which of the following is the frequency
of the heterozygous condition?
A. 16 percent
B. 32 percent
C. 40 percent
D. 48 percent
17.Which of the following is known to be involved
in the photoperiodic flowering response of
angiosperms?
A. Auxin
B. Cytochrome
C. Phytochrome
D. Gibberellins
18.Which of the following tends to be highest on
the trophic pyramid?
A. Primary consumers
B. Herbivores
C. Primary carnivores
D. Primary producers
19.A form of species interaction in which one of the
species benefits while the other is unaffected is
called
A. parasitism.
B. mutualism.
C. commensalism.
D. symbiosis.
20.The transfer of DNA between two bacterial cells
connected by sex pili is known as
A. specialized transduction.
B. conjugation.
C. transformation.
D. generalized transduction.