chapter 8 exam 4 Flashcards
1
Q
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.
A
A. Asexual reproduction.
2
Q
Which of the following statements regarding sexual and asexual reproduction is true?
A) Cell division only occurs after sexual reproduction.
B) Only offspring from asexual reproduction inherit traits from two parents.
C) Sexual reproduction typically includes the development of unfertilized eggs.
D) Sexual reproduction is more likely to increase genetic variation than is asexual reproduction.
A
D. Sexual reproduction is more likely to increase genetic variation than is asexual reproduction.
3
Q
Asexual reproduction requires a minimum of ________ individual(s).
A) 0
B) 1
C) 2
D) 3
A
B. 1.
4
Q
With the exception of identical twins, siblings who have the same two biological parents are likely to look similar, but not identical, to each other because they have:
A) identical chromosomes, but different genes.
B) identical genes but different chromosomes.
C) the same combination of traits, but different genes.
D) a similar but not identical combination of genes.
A
D. A similar but not identical combination of genes.
5
Q
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 is the basis of both sexual and asexual reproduction.
D) Cell division is common in eukaryotes but rare in prokaryotes.
A
D. Cell division is common in eukaryotes but rare in prokaryotes.
6
Q
Which of the following statements regarding prokaryotes is false?
A) Prokaryotic chromosomes are more complex than those of eukaryotes.
B) Most prokaryotes reproduce by binary fission.
C) Prokaryotic cells are generally smaller and simpler than eukaryotic cells.
D) In prokaryotes, daughter chromosomes are separated by an active movement away from each other and the growth of a new plasma membrane between them.
A
A. Prokaryotic chromosomes are more complex than those of eukaryotes.
7
Q
Eukaryotic chromosomes differ from prokaryotic chromosomes in that they:
A) are simpler.
B) are circular in structure.
C) include fewer proteins.
D) are housed in a membrane-enclosed nucleus.
A
D. Are housed in a membrane-enclosed nucleus.
8
Q
Which of the following helps maintain the structure of chromosomes and control the activity of genes?
A) the nuclear membrane
B) proteins
C) centromeres
D) ribosomes
A
B. Proteins.
Note: DNA wraps around histone proteins to form chromatins. Chromatins fold and condense into chromosomes before mitosis occurs.
9
Q
Sister chromatids are:
A) found right after a cell divides.
B) joined together at a centromere.
C) made only of DNA.
D) unique to prokaryotes.
A
B. Joined together at a centromere.
Note: Chromosomes are usually only seen after DNA replication is already complete and therefore always seen together as sister chromatids.
10
Q
Prior to mitosis, each chromosome of a eukaryotic cell consists of a pair of identical structures called:
A) chromatin.
B) sister chromosomes.
C) nucleoli.
D) sister chromatids.
A
D. Sister chromatids.
11
Q
Eukaryotic cells spend most of their cell cycle in which phase?
A) interphase
B) prophase
C) metaphase
D) telophase
A
A. Interphase.
12
Q
Which of the following occurs during interphase?
A) a reduction in the size of the nuclear membrane
B) cytokinesis
C) cell growth and duplication of the chromosomes
D) separation of newly formed DNA to opposite ends of the cell
A
C. Cell growth and duplication of the chromosomes.
13
Q
The genetic material is duplicated during:
A) the mitotic phase.
B) G1.
C) the S phase.
D) G2.
A
C. The S phase.
Note: S stands for “synthesis”. G stands for gap.
14
Q
The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called:
A) mitosis.
B) cytokinesis.
C) binary fission.
D) telophase.
A
B. Cytokinesis.
Note: Plant cells do not carry out cytokinesis. A cell plate is built to separate the newly divided cells.
15
Q
Looking into your microscope, you spot an unusual cell. Instead of the typical rounded cell shape, the cell has a very narrow middle separating two bulging ends. It sort of looks like the number 8! Then you realize that this cell is:
A) undergoing cytokinesis.
B) in the S phase of interphase.
C) in the G1 phase of interphase.
D) about to undergo mitosis.
A
A. Undergoing cytokinesis.
16
Q
The phase of mitosis during which the mitotic spindle begins to form is:
A) interphase.
B) prophase.
C) metaphase.
D) anaphase.
A
B. Prophase.
17
Q
During which phase of mitosis do the chromosomes line up on a plane equidistant from the two spindle poles?
A) prophase
B) metaphase
C) anaphase
D) telophase
A
B. Metaphase.
18
Q
At the start of mitotic anaphase:
A) the centromeres of each chromosome come apart.
B) the chromatid DNA replicates.
C) nuclear envelopes begin to form around the chromosomes.
D) equivalent and complete collections of chromosomes have reached the two poles.
A
A. The centromeres of each chromosome come apart.
19
Q
During which phase of mitosis does the nuclear envelope re-form?
A) anaphase
B) metaphase
C) prophase
D) telophase
A
D. Telophase.
20
Q
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
A
A. Formation of a cell plate.
21
Q
Which of the following features likely accounts for the difference between plant and animal cell cytokinesis?
A) Animal cells lack the microfilaments required for forming a cleavage furrow.
B) Animal cells lack chloroplasts.
C) Plant cells have cell walls.
D) Plant cells have two sets of chromosomes; animal cells have one set of chromosomes.
A
C. Plant cells have cell walls.
22
Q
Which of the following must occur for a plant or animal to grow and develop normally?
A) The organism must receive a supply of the appropriate hormones from its parents.
B) The organism must be able to control the timing and rate of cell division in different parts of its body.
C) Sufficient light must be available to stimulate cell division.
D) Sufficient oxygen must be available to stimulate cell division.
A
B. The organism must be able to control the timing and rate of cell division in different parts of its body.
23
Q
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.
A
B. Density-dependent inhibition.
Note: Cancer cells don’t follow this rule and start piling on top of regular cells and form a “lump” of cells. Therefore, you frequently see cancer develop as a “lump”.
24
Q
As a patch of scraped skin heals, the cells fill in the injured area but do not grow beyond that. This is an example of:
A) density-independent inhibition.
B) density-dependent inhibition.
C) anchorage independence.
D) growth factor inhibition.
A
B. Density-dependent inhibition.
25
Which of the following is probably the main factor responsible for the phenomenon of density-dependent inhibition?
A) a local accumulation of growth-inhibiting factors
B) cells' innate ability to "sense" when the organ of which they are a part has no need for additional cells
C) a local deficiency of nutrients
D) physical contact of cell-surface proteins between adjacent cells.
D. Physical contact of cell-surface proteins between adjacent cells.
26
Mature human nerve cells and muscle cells:
A) become cancerous more easily than other cell types.
B) continue to divide throughout their lifetime.
C) are permanently in a state of nondivision.
D) cease dividing after a predetermined number of cell generations.
C. Are permanently in a state of nondivision.
Note: They can be said to be in the "G0" phase.
27
Which of the following statements regarding the cell-cycle control system is false?
A) The cell-cycle control system receives messages from outside the cell that influence cell division.
B) The cell-cycle control system triggers and controls major events in the cell cycle.
C) The cell-cycle control system includes three key checkpoints to complete a cell cycle.
D) The cell-cycle control system operates independently of the growth factors.
D. The cell-cycle control system operates independently of the growth factors.
Note: Most cells require growth factors to grow. Common examples of growth factors are EGF and PDGF. On the other hand, most cancer cells do not need growth factors to grow because they either have a constitutively active growth factor receptor (e.g. EGFR) or some downstream signals of the growth factor have become spontaneously active (e.g. Ras, Raf, Myc, etc).
28
You are asked to culture an unidentified sample of animal tissue. You notice that the cells seem to fail to exhibit density-dependent inhibition. The source of this tissue sample is most likely:
A) a cancer.
B) skin.
C) a fetal liver.
D) the sperm-producing tissue of the testis.
A. A cancer.
29
A benign tumor differs from a malignant tumor in that a benign tumor:
A) is cancerous.
B) spreads from the original site.
C) does not metastasize.
D) never causes health problems.
C. Does not metastasize.
30
Which of the following shows the greatest promise as a cancer chemotherapy agent?
A) a drug that interferes with cellular respiration
B) a drug that prevents mitotic spindle from forming
C) a drug that prevents crossing over
D) a drug that prevents tetrad formation
B. A drug that prevents mitotic spindle from forming.
Note: Most traditional chemotherapy drugs inhibit mitotic spindle formation. Therefore, they also kill any cells that tend to divide actively. Your hair follicle cells and intestinal lining are also dividing actively all the time. Therefore, these chemotherapeutic agents also kill those cells, resulting in hair loss and nausea and diarrhea.
31
Which of the following statements regarding the function of mitosis is false?
A) Mitosis allows organisms to grow.
B) Mitosis allows organisms to generate genetic diversity.
C) Mitosis allows organisms to reproduce asexually.
D) Mitosis allows organisms to repair tissues.
B. Mitosis allows organisms to generate genetic diversity
32
1) Two chromosomes in a nucleus that carry genes controlling the same inherited characteristics are:
A) homologous chromosomes.
B) heterologous chromosomes.
C) complementary chromosomes.
D) parallel chromosomes.
A
33
2) Which of the following statements regarding mitosis and meiosis is false?
A) Meiosis only occurs in the ovaries and testes.
B) All 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.
C
Note: meiosis produces daughter cells with half the number of chromosomes, not mitosis
34
3) Which of the following statements is false?
A) Gametes are haploid cells.
B) Two haploid cells fuse during fertilization.
C) An X chromosome is an autosome.
D) A zygote is a fertilized egg.
C
35
4) During which stage of meiosis do synapsis and crossing over occur?
A) interphase I
B) prophase I
C) prophase II
D) metaphase I
B
36
5) Which of the following options correctly describes the behavior of a tetrad during anaphase I of meiosis?
A) It goes intact to one pole of the dividing cell.
B) It splits into two pairs of sister chromatids, and one pair goes to each pole of the dividing cell.
C) It splits into two pairs of homologous, nonsister chromatids, and one pair goes to each pole of the dividing cell.
D) It splits into four chromosomes, which distribute in random pairs to the two poles of the dividing cell.
B
37
6) Which of the following statements regarding the differences between mitosis and meiosis is false?
A) In meiosis four daughter cells are produced, whereas in mitosis two daughter cells are produced.
B) Cells produced by mitosis are diploid, whereas cells produced by meiosis are haploid.
C) In mitosis cytokinesis occurs once, whereas in meiosis cytokinesis occurs twice.
D) Crossing over is a phenomenon that creates genetic diversity during mitosis.
D
Note: crossing over involves exchange of parts of the homologous pair. This substantially increases the genetic diversity of offspring.
38
7) Which of the following statements regarding mitosis and meiosis is false?
A) Mitosis provides for growth and tissue repair.
B) Meiosis provides for asexual reproduction.
C) In mitosis, the chromosomes replicate only once in the preceding interphase.
D) All the events unique to meiosis occur during meiosis I.
B
Note: meiosis is for sexual reproduction
39
8) Both mitosis and meiosis are preceded by
A) prometaphase.
B) interphase.
C) prophase.
D) telophase.
B
Note: Copying of DNA is complete BEFORE the occurrence of both mitosis and meiosis.
40
9) Independent orientation of chromosomes at metaphase I and random fertilization are most like
A) shuffling cards and dealing out hands of poker.
B) cutting up a pie into eight even-sized slices.
C) alphabetizing files in a filing cabinet.
D) pairing up similar socks after washing your clothes.
A
Note: This is called independent assortment
41
10) Independent orientation of chromosomes at metaphase I results in an increase in the number of
A) gametes.
B) homologous chromosomes.
C) possible combinations of characteristics.
D) sex chromosomes.
C
42
11) Which of the following statements regarding genetic diversity is false?
A) Genetic diversity is enhanced by random fertilization.
B) Genetic diversity is enhanced by independent orientation of chromosomes at metaphase I.
C) Genetic diversity is enhanced by mitosis.
D) Genetic diversity is enhanced by crossing over during meiosis.
C
43
12) At a chiasma, two ________ are attached to each other.
A) homologous or non-sister chromatids
B) homologous or sister chromatids
C) non-homologous chromosomes
D) daughter cells
A
Note: crossing over occurs between the paternal chromosome and the maternal homologous chromosome.
44
13) Without crossing over
A) cells could not complete meiosis.
B) meiosis could not produce haploid gametes.
C) only a small number of unique gametes could be produced by a single individual.
D) genetic recombination of linked genes could not occur.
D
Note: linked genes refer to genes located on the same chromosome.
45
14) Karyotyping
A) shows chromosomes as they appear in metaphase of meiosis II.
B) can reveal alterations in chromosome number.
C) examines points of crossing over.
D) reveals the presence of cancerous genes.
B
46
15) Which of the following statements regarding Down syndrome is false?
A) Trisomy 21 is the cause of Down syndrome.
B) Down syndrome is the most common serious birth defect in the United States.
C) People with Down syndrome usually have a shorter life span than normal.
D) Down syndrome is least likely to be seen in the infants of mothers over 40.
D
Note: older mothers are more likely to have babies born with Down syndrome
47
16) 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.
C
48
17) Which of the following statements about nondisjunction is false?
A) Nondisjunction in meiosis can affect autosomes and sex chromosomes.
B) In mammals, extra copies of the Y chromosome are typically inactivated.
C) In general, a single Y chromosome is enough to produce "maleness."
D) Women with a single X chromosome have Turner syndrome and are sterile.
B
49
18) If a chromosome fragment breaks off and then reattaches to the original chromosome, but in the reverse direction, the resulting chromosomal abnormality is called a(n)
A) deletion.
B) inversion.
C) translocation.
D) reciprocal translocation.
B
50
19) Cancer is not usually inherited because
A) the chromosomal changes in cancer are usually confined to somatic cells.
B) people with cancer usually die before reproducing.
C) the causes of cancer are not usually genetic.
D) the cancerous cells usually interfere with the ability to produce gametes.
A
Note: somatic cells mean all cells in the body except for gamete making cells
51
20) For a human egg, meiosis I occurs:
A) during ovulation
B) at the moment of fertilization
C) immediately after oogonium formation
D) during fetal development
E) randomly during egg development
A
52
21) For a human egg, meiosis II occurs:
A) during ovulation
B) at the moment of fertilization
C) immediately after oogonium formation
D) during fetal development
E) randomly during egg development
B
53
22) For human egg development, Meiosis I and II of cytoplasm result in:
A) 1 egg and up to 3 polar bodies
B) identical twins
C) fraternal twins
D) fertilized egg
E) 4 identical eggs
A
Note: Both Meiosis I and II of egg cell division are unequal, resulting in a big egg and 3 much smaller polar bodies
54
23) The tortoiseshell pattern on a cat
A) usually occurs in males.
B) is the result of a homozygous recessive condition.
C) results from X chromosome inactivation.
D) is a result of alleles on the Y chromosome.
C
55
8.2 Art Questions
1) What type of cell is shown?
A) animal cell in metaphase
B) animal cell in telophase
C) plant cell in metaphase
D) plant cell in telophase
D
56
2) According to the graph, at what maternal age does the incidence of Down syndrome begin to increase substantially?
A) about 26 or 27
B) about 31 or 32
C) about 37 or 38
D) about 42 or 43
C
57
3) If these four cells resulted from cell division of a single cell with diploid chromosome number 2n = 4, what best describes what just occurred?
A) normal meiosis
B) translocation
C) inversion
D) nondisjunction
D
58
3) Mendel conducted his most memorable experiments on
A) peas.
B) roses.
C) guinea pigs.
D) fruit flies.
A
59
4) 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.
D
60
5) Which of the following statements regarding cross-breeding and hybridization is false?
A) The offspring of two different varieties are called hybrids.
B) The parental plants of a cross are the P generation.
C) The hybrid offspring of a cross are the P1 generation.
D) The hybrid offspring of an F1 cross are the F2 generation.
C
Note: the hybrid offspring is called F1. F stands for filial
61
6) A monohybrid cross is
A) the second generation of a self-fertilized plant.
B) a breeding experiment in which the parental varieties have only one trait in common.
C) a breeding experiment in which the parental varieties differ in only one character.
D) a breeding experiment in which the parental varieties have only one prominent trait.
C
62
7) 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.
B
Note: That's called heterozygous, homozygous is when the two alleles are the same
63
8) Research since Mendel's time has established that the law of the segregation of genes during gamete formation
A) applies to all forms of life.
B) applies to all sexually reproducing organisms.
C) applies to all asexually reproducing organisms.
D) is invalid.
B
64
9) All the offspring of a cross between a black-eyed fly and an orange-eyed fly have black eyes. This means that the allele for black eyes is ________ the allele for orange eyes.
A) codominant to
B) recessive to
C) more aggressive than
D) dominant to
D
65
10) All the offspring of a cross between a black-eyed fly and an orange-eyed fly have black eyes. What is the expected phenotypic ratio of a cross between two orange-eyed flies?
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
B
Note: you have to homozygous recessive to be orange-eyed in this case. Crossing 2 homozygous recessive will always result in the recessive phenotypes only!
66
11) 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
D
67
12) The phenotypic ratio resulting from a dihybrid cross showing independent assortment is expected to be
A) 1:2:1.
B) 3:1.
C) 9:1:1:3.
D) 9:3:3:1.
D
68
13) If A is dominant to a and B is dominant to b, what is the expected phenotypic ratio of the cross: AaBb × AaBb?
A) 16:0:0:0
B) 8:4:2:2
C) 1:1:1:1
D) 9:3:3:1
D
69
14) Mendel's law of independent assortment states that
A) chromosomes sort independently of each other during mitosis and meiosis.
B) independent sorting of genes produces polyploid plants under some circumstances.
C) each pair of alleles segregates independently of the other pairs of alleles during gamete formation.
D) genes are sorted concurrently during gamete formation.
C
70
16) A testcross is
A) a mating between an individual of unknown genotype and an individual homozygous recessive for the trait of interest.
B) a mating between an individual of unknown genotype and an individual heterozygous for the trait of interest.
C) a mating between two individuals heterozygous for the trait of interest.
D) a mating between two individuals of unknown genotype.
A
Note: the "unknown" genotype should be either homozygous dominant or heterozygous but both showing the dominant phenotype.
71
18) Assuming that the probability of having a female child is 50% and the probability of having a male child is also 50%, what is the probability that a couple's first-born child will be female and that their second-born child will be male?
A) 20%
B) 25%
C) 50%
D) 75%
B
Note: please note that this is theoretical. The probability of having a male child is actually around 50.5% and that of a female child is around 49.5%. This is because Y sperm actually swims a bit faster than X sperms probably because Y sperm carries less genetic material as "cargo"
72
19) 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
C
Note: both parents must be Dd as they have normal hearing but carry the recessive gene
73
20) 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
A
Note: a carrier means someone who don't have symptoms but carry the gene for the condition, usually in the heterozygous condition.
74
21) Most genetic disorders of humans are caused by
A) multiple alleles.
B) recessive alleles.
C) a mutation that occurs in the egg, sperm, or zygote.
D) dominant alleles.
B
75
22) Most people afflicted with recessive disorders are born to parents who were
A) both affected by the disease.
B) not affected at all by the disease.
C) slightly affected by the disease, showing some but not all of the symptoms.
D) subjected to some environmental toxin that caused the disease in their children.
B
Note: Both parents in this case are heterozygous
76
23) 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.
C
77
24) Amniocentesis and chorionic villus sampling allow for ________ and ________ of the fetus so that it can be tested for abnormalities.
A) imaging . . . karyotyping
B) sexing . . . imaging
C) karyotyping . . . biochemical testing
D) direct observation . . . biochemical testing
C
Note: chorionic villus sampling (CVS) is typically done at 10-12 weeks' gestation, and amniocentesis is done at 15-18 weeks' gestation.
78
25) Which of the following statements regarding prenatal testing is false?
A) Results from chorionic villus sampling come faster than from amniocentesis.
B) Chorionic villus sampling is typically performed later in the pregnancy than amniocentesis.
C) Ultrasound imaging has no known risk.
D) Chorionic villus sampling and amniocentesis are usually reserved for pregnancies with higher than usual risks of complications.
B
79
26) Which of the following statements regarding genetic testing is false?
A) Genetic testing before birth requires the collection of fetal cells.
B) Carrier testing helps determine if a person carries a potentially harmful disorder.
C) The screening of newborns can catch inherited disorders right after birth.
D) Most human genetic diseases are treatable if caught early.
D
Note: Most genetic disease are not really treatable. Currently the only option is to have an abortion. Worldwide statistically, 90%+ of parents who choose to do genetic testing usually will opt for an abortion if a genetic disease is detected. Most european and Asian countries have very little restrictions on abortions.
80
27) For most sexually reproducing organisms, Mendel's laws
A) cannot strictly account for the patterns of inheritance of many traits.
B) explain the reasons why certain genes are dominant.
C) help us understand the global geographic patterns of genetic disease.
D) clarify the phenomenon of incomplete dominance.
A
Note: that's true because many traits don't follow the single-gene inheritance pattern.
81
28) All the offspring of a cross between a red-flowered plant and a white-flowered plant have pink flowers. This means that the allele for red flowers is ________ to the allele for white flowers.
A) dominant
B) codominant
C) incompletely dominant
D) recessive
C
82
29) 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.
A
83
30) Which of the following is an example of incomplete dominance in humans?
A) sickle-cell disease
B) hypercholesterolemia
C) skin color
D) ABO blood groups
B
84
31) The expression of both alleles for a trait in a heterozygous individual illustrates
A) incomplete dominance.
B) codominance.
C) pleiotropy.
D) polygenic inheritance.
B
85
32) A person with AB blood illustrates the principle of
A) incomplete dominance.
B) codominance.
C) pleiotropy.
D) polygenic inheritance.
B
86
33) Which of the following statements is false?
A) Incomplete dominance supports the blending hypothesis.
B) The four blood types result from various combinations of the three different ABO alleles.
C) ABO blood groups can provide evidence of paternity.
D) The impact of a single gene on more than one character is called pleiotropy.
A
Note: incomplete dominance does not mean there are blending of gene products. It usually means having one copy of the gene result in less than normal amount of gene product (e.g. enzyme) to produce the phenotype as having 2 copies of the gene.
87
34) Which of the following statements regarding sickle-cell disease is false?
A) Persons who are heterozygous for sickle-cell disease are also resistant to malaria.
B) Sickle-cell disease causes white blood cells to be sickle-shaped.
C) All of the symptoms of sickle-cell disease result from the actions of just one allele.
D) About one in ten African-Americans is a carrier of sickle-cell disease.
B
Note: sickle-cell disease causes RBC to be sickle-shaped when there is not enough oxygen around
88
36) 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
D
89
38) The individual features of all organisms are the result of
A) genetics.
B) the environment.
C) the environment and individual needs.
D) genetics and the environment.
D
90
39) The chromosome theory of inheritance states that
A) chromosomes that exhibit mutations are the source of genetic variation.
B) the behavior of chromosomes during meiosis and fertilization accounts for patterns of inheritance.
C) the behavior of chromosomes during mitosis accounts for inheritance patterns.
D) humans have 46 chromosomes.
B
91
40) Genes located close together on the same chromosomes are referred to as ________ genes and generally ________.
A) linked . . . sort independently during meiosis
B) homologous . . . are inherited together
C) linked . . . do not sort independently during meiosis
D) codependent . . . do not sort independently during meiosis
C
92
41) Linked genes generally
A) do not follow the laws of independent assortment.
B) show incomplete dominance.
C) reflect a pattern of codominance.
D) show pleiotropy.
A
93
42) You conduct a dihybrid cross. A ________ ratio would make you suspect that the genes are linked.
A) 3:1
B) 1:1:1:1
C) 12:1:1:4
D) 9:3:3:1
C
Note: The ratio can be due to crossing over. There are no pre-determined ratios for linked genes. The frequencies of recombinants occurring for linked genes depends on the distance between those genes on the same chromosome.
94
43) Crossing over ________ genes into assortments of ________ not found in the parents.
A) recombines unlinked . . . genes
B) recombines linked . . . alleles
C) combines unlinked . . . alleles
D) combines linked . . . genes
B
95
44) The mechanism that "breaks" the linkage between linked genes is
A) pleiotropy.
B) codominance.
C) independent assortment.
D) crossing over.
D
96
45) Which of the following kinds of data could be used to map the relative position of three genes on a chromosome?
A) the frequencies with which the genes exhibit incomplete dominance over each other
B) the frequencies of mutations in the genes
C) the frequencies with which the genes are inherited from the mother and from the father
D) the frequencies with which the corresponding traits occur together in offspring
D
Note: almost nobody does that anymore. It is just a technique that researcher used before the easy availability of whole-genome sequencing
97
46) What is the normal complement of sex chromosomes in a human male?
A) two Y chromosomes
B) two X chromosomes and one Y chromosome
C) one X chromosome and one Y chromosome
D) one Y chromosome
C
98
47) The sex chromosome complement of a normal human female is
A) XO.
B) XX.
C) XY.
D) YY.
B
99
48) How many sex chromosomes are in a human gamete?
A) one
B) two
C) three
D) four
A
100
50) Given the sex determination system in bees, we can expect that
A) female bees will produce eggs by meiosis, while male bees will produce sperm by mitosis.
B) female bees will produce eggs by mitosis, while male bees will produce sperm by meiosis.
C) male and female bees will produce sperm and eggs by meiosis.
D) male and female bees will produce sperm and eggs by mitosis.
A
Note: males in bees are all haploid (one set of chromosome) and female bees are diploid
101
51) What is meant by the statement that "male bees are fatherless"?
A) Male bees don't play a role in the rearing of bee young.
B) Male bees are produced by budding.
C) Male bees develop from unfertilized eggs.
D) The queen bee's mate dies before the male eggs hatch.
C
Note: when a male bee fertilizes the queen, the queen produces mostly female offspring as "workers' of the colonies. A small portion of the queen's egg are not fertilized and develop into male bees
102
52) 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.
B
Note: X chromosomes carry a lot more gene that Y chromosomes and most of those do NOT have any counterparts on the Y chromosome.
103
53) 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.
B
104
54) A color-blind woman marries a man who is not color-blind. All of their sons, but none of their daughters, are color-blind. Which of the following statements correctly explains these results?
A) The gene for color vision is incompletely dominant to the gene for sex determination.
B) The gene for color vision is codominant with the gene for sex determination.
C) The gene for color vision is found on the X chromosome.
D) The gene for color vision is found on the Y chromosome.
C
Note: You are expected to know all outcome of color-blindness crossings (e.g. carrier female having x normal vision male, carrier female x color-blind male; non carrier female x color-blind male; color-blind female x normal vision male, etc...) There will be a variation to this question and you need to be able to work out ALL possible combinations yourself!
105
55) Sex-linked conditions are more common in men than in women because
A) men acquire two copies of the defective gene during fertilization.
B) men need to inherit only one copy of the recessive allele for the condition to be fully expressed.
C) the sex chromosomes are more active in men than in women.
D) the genes associated with the sex-linked conditions are linked to the Y chromosome, which determines maleness.
B
Note: Men always get Y from the father. Y chromosome is a lot shorter than the X chromosomes and there are no counterparts on the Y chromosome for a lot of functions carried by the X chromosome. Whatever a man inherit on the X chromosome from his Mother will be expressed.
106
57) Female inheritance patterns cannot be analyzed by simply studying the X chromosome because
A) the X chromosome is too large to analyze effectively
B) the X chromosome sometimes exchanges genetic information with the Y chromosome
C) the X chromosome is obtained from both father and mother.
D) one X chromosome is deactivated in females.
C
107
9.2 Art Questions
1) Which plants in this figure must all be heterozygous?
A) purple-flowered plants in the P generation
B) white-flowered plants in the P generation
C) purple-flowered plants in the F1 generation
D) purple-flowered plants in the F2 generation
C
108
2) According to this figure, heterozygotes for this form of hypercholesterolemia suffer from the disease because they
A) produce an abnormally shaped LDL receptor.
B) don't produce any LDL receptors.
C) produce too many LDL receptors.
D) don't produce enough LDL receptors.
D
109
Scenario Questions
1) 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.
B
Note: AOx BO will result in AB; AO; BO; OO at 1:1:1:1 ratio (25% chance of getting all 4 blood types)
You are also expected to know the result of all crossing combination of ABO blood groups. There will be a variation to this question to test your ability to come up with the right combination yourself!
110
2) 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.
C
