276 ❯ STEP 5. Build Your Test-Taking Confidence
- D—Cell walls are present in prokaryotes but not
eukaryotic animal cells. Ribosomes and cell mem-
branes are present in both of them. Chloroplasts
and large central vacuoles are not seen in either of
them. Animal cells have small vacuoles. - A—The oxygen released by plants is produced
during the light reactions of photosynthesis. The
main inputs to the light reactions are water and
light. Water is the source of the oxygen. - B—Endotherms are organisms whose metabolic
rates do not respond to shifts in environmental
temperature. - B—A frameshift mutation is one in which the
reading frame for the protein construction
machinery is shifted. It is a deletion or addition
of nucleotides in a number that is nota multiple
of 3. Often this can lead to premature stop codons,
which lead to nonfunctional proteins. - C
- C—We can see from the data that m and f have
the highest crossover frequency. They must
therefore be farthest apart of any pair along the
chromosome. This leaves only answer choice C. - C—Memory B cells are able to recognize foreign
invaders if they come back into our systems and
lead to a more rapid and efficient attack on the
invader. - C—Polygenic traits are traits that require the
input of multiple genes to determine the pheno-
type. Skin color is a classic example of a poly-
genic trait; three genes combine to provide the
various shades of skin tone seen in humans. - C—This is a classic example of Batesian mimicry.
- D—Crossover is most likely to occur between
two genes that are located far away from each
other on the same chromosome. - C—Meiosis reduces the number of chromo-
somes in an individual by half: 96 ÷ 2 =48. - D—The volume of the container is not a major
factor that affects enzyme efficiency. - C—The original question describes an organism
that can be classified as a K-selected population.
Individuals of this class tend to have fairly con-
stant size, low reproductive rates, and offspring
that require extensive care. - D—A detritivore is an organism that includes
the subcategory of decomposers. Fungi are
decomposers. - C—If 9 percent of the population is homozy-
gous recessive, this means that q^2 =0.09, and that
the square root of q^2 =0.30=q.This means that
p=0.70 since p+q=1. Thus, the percentage of
the population that is homozygous dominant: p^2 =
(0.7)^2 =0.49 or 49 percent. - A—All the other answer choices are violations of
the Hardy–Weinberg equilibrium. - C—Exergonic reactions give off energy, and
hydrolysis reactions are reactions that use water to
break apart a compound. Redox reactions are reac-
tions that involve the movement of electrons.
Dehydration reactions are reactions that bring two
molecules together, releasing water as a product. - D—Herbivores tend to be the primary con-
sumers of trophic pyramids, and thus would take
up the first level up from the bottom. - B—Stabilizing selection tends to eliminate the
extremes of a population, directional selection is a
shift toward one of the extremes, and disruptive
selection is the camel-hump selection in which the
two extremes are favored over the middle.
Sympatric speciation is the formation of new species
due to an inability to reproduce that is not caused
by geographic separation. Sexual selection is evolu-
tion of characters that aid in mate acquisition. - D—This is a lab experiment question based on
the material in Chapter 15. We threw it in here
just to remind you that you should not ignore
the concepts of this very important chapter. You
will be asked about these concepts on the exam. - B—Succession is an ecological process in which
landforms evolve over time in response to the
❯ Answers and Explanations for AP Biology Practice Exam 1
PART A: MULTIPLE-CHOICE QUESTIONS