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58. The correct answer is (E). Peroxisomes are intracellular vesicles that are similar to lysosomes. All
peroxisomes contain the enzyme catalase, which catalyzes the degradation of hydrogen peroxide to a
less toxic molecule.
59. The correct answer is (B).
Mitochondria are the so-called “powerhouses” of the cell, producing the
ATP necessary for cellular processes. Mitochondria also reproduce by dividing in two and contain DNA.
60. The correct answer is (A). Ribosomes are composed of protein and RNA. Protein synthesis is cata-
lyzed by this complex structural unit.
61. The correct answer is (C). Centrioles are organizing centers that are composed of a cylindrical array
of microtubules.
62. The correct answer is (D). Malpighian tubules lie in the hemocoel of insects, where the tubules are
bathed in blood. Fluid is absorbed into the tubules and water and salts are reabsorbed. Waste materi-
als then pass into the hindgut.
63. The correct answer is (C). Nephridia filter the extracellular fluid of the earthworm and reclaim valu-
able materials.

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Biology E/M Subject Test
275
ARCO
■ SAT II Subject Tests
w w w . p e t e r s o n s . c o m / a r c o
64. The correct answer is (A). Contractile vacuoles are responsible for maintaining water balance. These
structures are present in some protozoans.
65. The correct answer is (E). The functional unit of the vertebrate kidney is called the nephron. The
nephron consists of Bowman’s capsule and a long tubule. The tubule is divided into several, well-
characterized segments.
66. The correct answer is (D). Questions 66–69 refer to a dihybrid cross that follows simple Mende-
lian laws. The results of this mating can be demonstrated through the use of a Punnett square. Round
(R) and yellow (Y) are dominant traits, while wrinkled (r) and green (y) are recessive traits. Thus, the
parents’ genotypes may be represented as RrYy. The cross is then:
The Punnett square, then, is as illustrated:
Thus, the combination R and Y—yellow, rounded—is present in 9/16 of the offspring. This number
represents the expected proportion of offspring from the dihybrid cross that are yellow and rounded.