Download Biology-1 Exam Three There are a total of 68 questions on this exam

Biology-1
Exam Three
There are a total of 68 questions on this exam. Questions 1-57 are multiple choice (2 pts. each) and 58-68 are True/False (1 pt.
each). You can write on this exam but please put a ‘W’ on the top of this page if you choose to.
Multiple Choice: Choose the answer that best answers or completes the question.
1.
When animal cells are grown in a petri dish, they typically stop dividing once they have formed a single, unbroken layer on the
bottom of the dish. This arrest of division is an example of
a. cell constraint
b. density-dependent inhibition
c. cell division repression
d. growth factor desensitization
e. anchorage dependence
2.
The shape of a DNA molecule is most like
a. a set of railroad tracks.
b. a diamond ring.
c. a twisted rope ladder.
d. a gold necklace.
e. the letter X.
3. Chromatin fibers are
a. composed of DNA and protein
b. found in the nucleus of a cell
c. composed of microfilaments and actin filaments and are part of the cytoskeleton
d. found in the cytoplasm of the cell anchoring organelles
e. a and b only
4.
Which of the following statements are true concerning human somatic and/or gamete cells?
a. There are 23 homologous pairs in somatic cells
b. There are a total of 46 chromosomes in somatic cells
c. There are 2 sex chromosomes in somatic cells
d. There are 22 autosomes in gamete cells
e. all of the above are true
5.
Which of the following statements is false?
a. A typical body cell is called a somatic cell.
b. Gametes are haploid cells.
c. Somatic cells are diploid.
d. Gametes are made by mitosis.
e. A zygote is a fertilized egg.
6.
Homologous chromosomes:
a. are genetically identical
b. are similar in length
c. code for the same inherited traits
d. are formed during DNA replication
e. b and c are correct
7.
The alternate forms of one gene are called_______________.
a.
8.
chromatin
b. loci
c. alleles
d. codons
e. chromatids
The period between cell formation and cell division is called_________________.
a.
interphase
b. metaphase
c. anaphase
d. prophase
e. cytokinesis
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Biology-1
9.
Exam Three
During which stage of meiosis does crossing over occur?
a. interphase I
b. prophase I
c. interphase II
d. prophase II
e. metaphase I
10. Which of the following statements regarding cell division is false?
a. Cell division can reproduce an entire organism.
b. Cell division is necessary for development to occur.
c. Cell division ensures the continuity of life from generation to generation.
d. Cell division is the basis of both sexual and asexual reproduction.
e. Cell division is common in eukaryotes but rare in prokaryotes.
11. The phase of mitosis during which the nuclear envelope fragments and the nucleoli disappear is called
a.
interphase
b. prophase
c. metaphase
d. anaphase
e. telophase
12. The centromere is a region in which
a. sister chromatids are attached to one another
b. metaphase chromosomes become aligned
c. chromosomes are grouped during telophase
d. the nucleus is located prior to mitosis
e. new spindle microtubules form
13. What is a sister chromatid?
a. a chromosome in G1 of the cell cycle
b. a replicated chromosome
c. a chromosome found outside the nucleus
d. a special region that holds two centromeres together
e. another name for the chromosomes found in genetics
14. Which of the following is a feature of plant cell division that distinguishes it from animal cell division?
a. formation of a cell plate
b. formation of a cleavage furrow
c. lack of cytokinesis
d. production of four (rather than two) new cells per mitotic division
e. disappearance and subsequent reappearance of the nucleolus
15. During which phase of the cell cycle would you expect to see sister chromatids being separated?
a.
metaphase
b. prophase
c. telophase
d. anaphase
e. interphase
16. Which phase follows prophase and involves chromosomes lining up midway between the poles of the cell?
a.
metaphase
b. G1 phase
c. telophase
d. anaphase
e. interphase
17. Which of the following statements regarding mitosis and meiosis is false?
a. Meiosis only occurs in the ovaries and testes.
b. Sexual life cycles involve an alternation of diploid and haploid stages.
c. Mitosis produces daughter cells with half the number of chromosomes as the parent cell.
d. A normal human zygote has 46 chromosomes.
e. A haploid cell has half the chromosomes of a diploid cell.
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Biology-1
Exam Three
18. Nondisjunction occurs when
a. a portion of a chromosome breaks off and is lost
b. two chromosomes fuse into one
c. members of a chromosome pair fail to separate
d. an entire pair of chromosomes is lost during meiosis I
e. none of the above
19. The creation of genetically identical offspring by a single parent, without the participation of sperm and egg, is called
a. asexual reproduction
b. sexual reproduction
c. regeneration
d. spontaneous generation
e. fertilization
20. Eukaryotic chromosomes differ from prokaryotic chromosomes in that they
a. are simpler
b. have fewer genes
c. are circular in structure
d. include fewer proteins
e. are housed in a membrane-enclosed nucleus
21. Mendel conducted his most memorable experiments using
a.
peas
b. roses
c. guinea pigs
d. fruit flies
e. dogs
22. Varieties of plants in which self-fertilization produces offspring that are identical to the parents are referred to as
a. hybrids
b. the F2 generation
c. monohybrid crosses
d. true-breeding
e. parental
23. Which of the following statements regarding cross-breeding and genetic crosses is false?
a. The offspring of two different varieties are called hybrids.
b. A cross between two parental varieties produces the F1 generation.
c. The hybrid offspring of an F1 cross are the F2 generation.
d. In a monohybrid cross only one trait is being considered.
e. In a dihybrid cross no hybrids are produced.
24. What type of cell is shown to the right?
a. plant cell in anaphase
b. plant cell in metaphase
c. plant cell in telophase
d. plant cell in interphase
e. animal cell in telophase
25. Which of the following statements regarding genotypes and phenotypes is false?
a. The genetic makeup of an organism constitutes its genotype
b. An organism with two different alleles for a single trait is said to be homozygous for that trait
c. Alleles are alternate forms of a gene
d. The expressed physical traits of an organism are called its phenotype
e. The phenotypes of organisms with identical genotypes may be different as a result of their interaction with their environment
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Biology-1
Exam Three
26. All the offspring of a cross between a black-eyed mendelien and an orange-eyed mendelien have black eyes. This means that the
allele for black eyes is ________ the allele for orange eyes.
a. codominant to
b. incompletely dominant to
c. recessive to
d. more aggressive than
e. dominant to
27. The alleles of a gene are found at ________ chromosomes.
a. the same locus on non-homologous
b. different loci on homologous
c. different loci on non-homologous
d. the same locus on homologous
e. none of the above
28. The phenotypic ratio resulting from a dihybrid cross of two heterozygote individuals showing independent assortment is expected
to be,
a.
1:2:1
b. 3:1
c. 9:1:1:3
d. 9:3:3:1
e. 2:1
29. Mendel's law of independent assortment states that
a. chromosomes sort independently of each other during mitosis and meiosis.
b. genes sort independently of each other in animals but not in plants.
c. each pair of alleles assorts independently of the other pairs of alleles during gamete formation.
d. genes are sorted concurrently during gamete formation.
e. none of the above
30. Assuming that the probability of having a female child is 1/2 and the probability of having a male child is also 1/2, what is the
probability that a couple's first-born child will be female and that their second-born child will be male?
a.
1/5
b. ¼
c. ½
d. ¾
e. not enough information
31. All the offspring of a cross between a black-eyed Mendelian and an orange-eyed Mendelian have black eyes. What is the
expected phenotypic ratio of a cross between two orange-eyed Mendelian?
a. 3 black-eyed:1 orange-eyed
b. 0 black-eyed:1 orange-eyed
c. 1 black-eyed:3 orange-eyed
d. 1 black-eyed:0 orange-eyed
e. not enough information
32. A carrier of a genetic disorder who does not show symptoms is most likely to be ________ to transmit it to offspring.
a. heterozygous for the trait and able
b. heterozygous for the trait and unable
c. homozygous for the trait and able
d. homozygous for the trait and unable
e. heterozygous for the trait and unlikely
33. A person with AB blood illustrates the principle of
a. incomplete dominance
b. codominance
c. pleiotropy
d. polygenic inheritance
e. none of the above
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Biology-1
Exam Three
34. Which of the following statements best explains why dominant alleles that cause lethal disorders are less common than recessive
alleles that cause lethal disorders?
a. Lethal disorders caused by dominant alleles are usually more severe than lethal disorders caused by recessive alleles.
b. Unlike lethal disorders caused by recessive alleles, lethal disorders caused by dominant alleles usually cause the death of the
embryo.
c. Most individuals carrying a lethal dominant allele have the disorder and die before they reproduce, whereas individuals
carrying a lethal recessive allele are more likely to be healthy and reproduce.
d. The presence of a lethal dominant allele causes sterility.
35. Which of the following terms refers to a situation where a single phenotypic character is determined by the additive effects of two
or more genes?
a. incomplete dominance
b. codominance
c. pleiotropy
d. polygenic inheritance
e. dominant inheritance
36. Imagine that beak color in a finch species is controlled by a single gene. You mate a finch homozygous for orange (pigmented)
beak with a finch homozygous for ivory (unpigmented) beak and get numerous offspring, all of which have a pale, ivory-orange
beak. This pattern of color expression is most likely to be an example of
a. incomplete dominance.
b. codominance.
c. pleiotropy.
d. polygenic inheritance.
e. crossing over.
37. Any gene located on a sex chromosome
a. is called a recessive gene
b. is called a sex-linked gene
c. will exhibit pleiotropy
d. will exhibit codominance
e. is recessive
38. What is the normal makeup of sex chromosomes in a human male?
a. two X chromosomes
b. two Y chromosomes
c. two X chromosomes and one Y chromosome
d. one X chromosome and one Y chromosome
e. one Y chromosome
39. Recessive X-linked traits are more likely to be expressed in a male fruit fly than a female fruit fly because
a. males are haploid.
b. the male's phenotype results entirely from his single X-linked gene.
c. the male chromosome is more fragile than the female chromosome.
d. the male chromosome is more susceptible to mutations.
e. all of the above
40. Dr. Smith's parents have normal hearing. However, Dr. Smith has an inherited form of deafness. Deafness is a recessive trait that
is associated with the abnormal allele d. The normal allele at this locus, associated with normal hearing, is D. Dr. Smith's parents
could have which of the following genotypes?
a. DD and dd
b. dd and dd
c. Dd and Dd
d. DD and DD
e. Dd and DD
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Biology-1
Exam Three
41. The monomers of DNA and RNA are
a. amino acids
b. monosaccharides
c. nucleotides
d. fatty acids.
e. nucleic acids
42. If one strand of DNA is CGGTAC, the corresponding strand would be
a. GCCTAG.
b. CGGTAC.
c. GCCAUC.
d. TAACGT.
e. GCCATG.
43. Which of the following statements regarding DNA is false?
a. DNA uses the sugar deoxyribose
b. DNA uses the nitrogenous base uracil
c. DNA is a nucleic acid
d. One DNA molecule can include four different nucleotides in its structure
e. DNA molecules have a sugar-phosphate backbone.
44. Which of the following statements regarding a DNA double helix is always true?
a. The amount of adenine is equal to the amount of uracil, and the amount of guanine is equal to the amount of cytosine.
b. The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of uracil.
c. The amount of adenine is equal to the amount of guanine, and the amount of thymine is equal to the amount of cytosine.
d. The amount of adenine is equal to the amount of cytosine, and the amount of guanine is equal to the amount of thymine.
e. The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine.
45. Which of the following represents a similarity between RNA and DNA?
a. both are double-stranded.
b. the presence of uracil
c. nucleotides consisting of a phosphate, sugar, and nitrogenous base
d. both are found exclusively in the nucleus.
e. They are both polymers of amino acids
46. DNA replication
a. occurs through the addition of nucleotides to the end of the DNA molecule.
b. results in the formation of four new DNA strands.
c. produces two daughter DNA molecules that are complementary to each other.
d. uses each strand of a DNA molecule as a template for the creation of a new strand.
e. begins when two DNA molecules join together to exchange segments.
47. Multiple origins of replication on the DNA molecules of eukaryotic cells serve to
a. remove errors in DNA replication.
b. create multiple copies of the DNA molecule at the same time.
c. shorten the time necessary for DNA replication.
d. reduce the number of "bubbles" that occur in the DNA molecule during replication.
e. assure the correct orientation of the two strands in the newly growing double helix.
48. Which of the following enzymes catalyzes the elongation of a new DNA strand?
a. helicase
b. primase
c. ligase
d. RNA polymerase
e. DNA polymerase
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Biology-1
Exam Three
49. Which of the following terms describes how the strands (backbones) of the DNA run in opposite directions?
a. semiconservative
b. antiparallel
c. complementary
d. identical
e. none of the above
50. The lagging strand which is formed during DNA replication
a. grows from the 5 prime end
b. is synthesized continuously
c. is synthesized in fragments
d. is antiparallel to the strand of DNA being copied
e. c and d
51. Which of the following is true concerning the 5 prime end of one strand of the DNA double helix?
a. The 5 prime carbon is attached to a hydroxyl group
b. The 5 prime carbon is attached to a phosphate group
c. During DNA replication, the newly synthesized DNA grows from the 5 prime end
d. The 5 prime end of one strand is next to (across from) the 5 prime end of the other strand
e. None of the above are true
52. When one DNA molecule is copied to make two DNA molecules, the new DNA contains
a. none of the parent DNA
b. 25% of the parent DNA
c. 50% of the parent DNA
d. 75% of the parent DNA
e. 100% of the parent DNA
53. How many origins of replication and how many replication forks are shown?
a. 3 origins and 3 replication forks
b. 3 origins and 6 replication forks
c. 6 origins and 3 replication forks
d. 6 origins and 6 replication forks
e. 6 origins and 12 replication forks
54. The genetic material is duplicated during
a. the mitotic phase
b. G1
c. the S phase
d. G2
e. cytokinesis
55. You are asked to culture (grow) an unidentified sample of animal tissue. You notice that the cells seem to fail to exhibit densitydependent inhibition and grow without the addition of growth factors. The source of this tissue sample is most likely
a. a scar
b. a cancer
c. skin
d. a fetal liver
e. the sperm-producing tissue of the testis
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Biology-1
Exam Three
After reading the following paragraph, answer the questions (56-57) below.
A woman has been trying to conceive for several years, unsuccessfully. At a fertility clinic, they discover that she has blocked
fallopian tubes. Using modern technologies, some of her eggs are removed, fertilized with her husband's sperm, and implanted
into her uterus. The procedure is successful, but the couple discovers that their new son is color-blind and has blood type O. The
woman claims that the child can't be theirs since she has blood type A and her husband has type B. Also, neither parent is colorblind, although one grandparent (the woman's father) is also color-blind.
56. As a genetic counselor, you would explain to the parents that
a. the eggs must have been accidentally switched, since the baby's blood type has to match one of his parents.
b. each parent could have contributed one recessive allele, resulting in type O blood.
c. the eggs must have been accidentally switched, since a type A parent and a type B parent can have any type children except
O.
d. it is possible for the baby to have type O blood, since type O is inherited through a dominant allele.
e. the baby is theirs, since the blood types of parents have no relation to their children's blood types.
57. In regard to the baby's color blindness, a sex-linked recessive trait, you explain that
a. color blindness often appears randomly, even if neither parent is color-blind.
b. the baby's father must have a recessive allele for color blindness.
c. since color blindness is sex-linked, a son can inherit color blindness if his mother has the recessive color blindness allele.
d. the eggs must have been accidentally switched, since males inherit sex-linked traits only from their fathers.
e. since color blindness is recessive, both parents can pass it on, even if neither is color-blind.
True/False Questions. Read each statement carefully. If any portion of the statement is false, the entire statement is false.
A=True B=False
58. Malignant tumors can spread from one location of the body to another through blood or lymphatic vessels. (T/F)
59. Mitosis is nuclear division, while cytokinesis is cytoplasmic division. (T/F)
60. The mitotic spindle is composed of microtubules and is formed during prophase of mitosis. (T/F)
61. The formation of a cleavage furrow during cytokinesis suggests that mitosis is occurring in animal cells. (T/F)
62. During meiosis, DNA is duplicated twice. (T/F)
63. Trisomy 21 causes the condition known as Down Syndrome and involves the inheritance of three copies of chromosome 21. (T/F)
64. The second division of meiosis is like mitosis because sister chromatids are separated. (T/F)
65. Heterozygous individuals have the same alleles on both homologous chromosomes. (T/F)
66. Dominant alleles always code for traits that are more common in a population. (T/F)
67. Recessive inheritance means that an individual must inherit one recessive allele to show a trait (disease). (T/F)
68. The diploid number of humans is 46. (T/F)
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