vv) Chapter 15 Brooker - using chapter 13 Campbell, chapters 10 & 13 Mader and others
4) If the DNA content of a diploid cell in the G1 phase of the cell cycle is x, then the DNA content of the same cell at metaphase of meiosis I will be A) 0.25x. B) 0.5x. C) x. D) 2x. 5) If we continue to follow the cell lineage from question 4, then the DNA content of a single cell at metaphase of meiosis II will be A) 0.25x. B) 0.5x. C) x. D) 2x.
4) D 5) C
1) A human cell containing 22 autosomes and a Y chromosome is A) a sperm. B) an egg. C) a zygote. D) a somatic cell of a male.
A
13) Which of the following processes might produce a human zygote with 45 chromosomes? A) an error in meiotic anaphase occurring in either an egg or sperm B) failure of the egg nucleus to be fertilized by the sperm C) failure of an egg to complete meiosis II D) incomplete cytokinesis during spermatogenesis after meiosis I
A
23) If a cell has completed meiosis I and the first cytokinesis, and is just beginning meiosis II, which of the following is an appropriate description of its genetic contents? A) It has half the amount of DNA as the cell that began meiosis. B) It has half the chromosomes but twice the DNA of the parent cell. C) It has one-fourth the DNA and one-half the chromosomes as the parent cell. D) It is genetically identical to another cell formed from the same meiosis I event.
A
27) Which of the following events happens at the conclusion of meiosis I? A) Homologous chromosomes of a pair are separated from each other. B) The chromosome number per cell remains the same. C) Sister chromatids are separated. D) Four daughter cells are formed.
A
3) Meiosis II is similar to mitosis in that A) sister chromatids separate during anaphase. B) DNA replicates before the division. C) the daughter cells are diploid. D) homologous chromosomes synapse.
A
45) Which of the following statements describes a major difference between mitosis and meiosis I in a diploid organism? A) Sister chromatids separate in mitosis, while homologous pairs of chromosomes separate in meiosis I. B) Sister chromatids separate in mitosis, while homologous pairs of chromosomes separate in meiosis II. C) DNA replication takes place prior to mitosis, but not before meiosis I. D) Only meiosis I results in daughter cells that contain identical genetic information.
A
50) During which of the following processes does independent assortment of chromosomes occur? A) in meiosis I only B) in meiosis II only C) in mitosis and meiosis I D) in mitosis and meiosis II
A
52) Independent assortment of chromosomes is a result of which of the following processes? A) the random way each pair of homologous chromosomes lines up at the metaphase plate during meiosis I B) the random combinations of eggs and sperm during fertilization C) the random distribution of the sister chromatids to the two daughter cells during anaphase II D) the diverse combination of alleles that may be found within any given chromosome
A
54) How does natural selection apply to sexual reproduction as opposed to asexual reproduction? A) Sexual reproduction results in many new gene combinations, some of which will lead to differential reproduction. B) Sexual reproduction results in the greatest number of new mutations. C) Sexual reproduction allows the greatest number of offspring to be produced. D) Sexual reproduction utilizes far less energy than asexual reproduction.
A
57) Imagine that there are 25 different species of protists living in a tide pool. Some of these species reproduce both sexually and asexually, and some of them can reproduce only asexually. The pool gradually becomes infested with disease-causing viruses and bacteria. Which species are more likely to thrive in the changing environment? A) The sexually reproducing species is likely to thrive. B) The asexually reproducing species is likely to thrive. C) Sexually and asexually reproducing species are equally likely to thrive. D) Neither species will be able to thrive.
A
57. During _______________ the homologous chromosome pairs separate in a random fashion leading to genetic diversity among the offspring. A. independent assortment B. metaphase C. anaphase II D. mitosis
A
58. If the diploid number of chromosomes for an organism is 52, what will the haploid number of chromosomes be? A. 26 B. 48 C. 112 D. 24
A
59. Which of the following statements is correct about the chromosomal position during mitosis and meiosis? A. During metaphase of mitosis the duplicated chromosomes are at the metaphase plate while during metaphase I of meiosis the bivalents are present at the metaphase plate. B. During metaphase I of meiosis the duplicated chromosomes are at the metaphase plate while during metaphase of mitosis the bivalents are present at the metaphase plate. C. During metaphase of mitosis the homologues separate while during metaphase I of meiosis the sister chromatids separate. D. During metaphase I of meiosis the homologues separate while during metaphase of mitosis the sister chromatids separate.
A
61. Which of the following statements is true about the life cycle of animals? A. The gametes are the haploid phase of the animals life cycle. B. The gametes are the diploid phase of the life cycle. C. The products of the haploid phase of the life cycle are larger than those of the diploid phase. D. Meiosis is not a necessary component of the animal life cycle.
A
62. Which statement is true about the life cycle of plants but not of animals? A. The gametophyte can be larger than the diploid generation. B. They use sexual reproduction to produce new offspring. C. They use meiosis in order to produce the gametes. D. They will have a haploid and diploid phase of the life cycle.
A
9. During which stage of meiosis does crossing-over occur? A. prophase I of meiosis I B. anaphase I of meiosis II C. telophase I of meiosis I D. prophase II of meiosis II E. anaphase II of meiosis I
A
60. During which phase of mitosis and meiosis will the state of the chromosome be the same? A. anaphase II and Anaphase B. prophase II and Prophase C. metaphase I and Metaphase D. telophase I and Telophase
A It is only during Metaphase II and Metaphase that the state of the chromosomes is the same.
21. Which does NOT occur in meiosis? A. two daughter cells at completion B. four daughter cells at completion C. two nuclear divisions D. formation of bivalents
A Meiosis produces four haploid daughter cells, includes two nuclear division and the formation of bivalents.
56. Which of the following events occurs during prophase I but does not occur during prophase of mitosis? A. crossing over B. nuclear envelope dissolves C. chromatin condenses into chromosomes D. centrioles appear in animal cells
A Crossing over is unique to Prophase I of Meiosis.
55. Identify which event will occur during Prophase I of meiosis but does not occur during prophase of mitosis. A. bivalents will form B. nuclear envelope will dissolve C. centrioles will form in animal cells D. chromatin will condense into chromosomes
A The formation of bivalents is unique to Prophase I of meiosis.
3. Some studies suggest that in patients with Alzheimer's disease, there is a defect in the way the spindle apparatus attaches to the kinetochore fibers. At which stage of mitotic division would one first expect to be able to visualize this problem? A. Prophase B. Metaphase c. Anaphase D. Telophase
A To ensure that the labeled deoxyadenine will be incorporated into the DNA of one of the daughter cells, we have to insert the nucleotide before DNA replication has been completed. Because replication occurs during S stage, we could introduce the deoxyadenine during G1 or S stage. Because G1 precedes S, the latest point the deoxyadenine could be added is the S stage.
47. Identify the chromosomal abnormalities as well as the physical features present in a person suffering from Turner syndrome.
An individual who inherits XO will show symptoms of Turners syndrome. Turner females are short with a broad chest and widely spaced nipples. They have a low posterior hairline and neck webbing. The ovaries, oviducts and uterus are very small and underdeveloped. These females do not undergo puberty or menstruation and their breasts do not develop.
1. Which of the following steps would NOT lead to variation of genetic material? A. crossing over of homologous chromosomes B. crossing over of sister chromatids C. the random alignment of the chromosomes during metaphase I D. the combination of sperm and egg genes
B
10) Which of the following statements describes an example of alternation of generations? A) A grandparent and grandchild each have dark hair, but the parent has blond hair. B) A diploid plant (sporophyte) produces a spore by meiosis that gives rise to a multicellular, haploid pollen grain (gametophyte). C) A diploid animal produces gametes by meiosis, and the gametes undergo fertilization to produce a diploid zygote. D) A haploid mushroom produces gametes by mitosis, and the gametes undergo fertilization, which is immediately followed by meiosis.
B
11. What is the importance of crossing-over? A. It provides extra genetic material for the daughter cells. B. It increases the likelihood that daughter cells contain different genetic material. C. It produces the proteins that are associated with DNA in chromosomes. D. It increases chromosome condensation. E. It separates the homologous chromosomes.
B
12) A triploid cell contains three sets of homologous chromosomes. If a cell of a diploid species that normally has 42 chromosomes per cell is triploid, this cell would be expected to have which of the following sets of chromosomes? A) 63 chromosomes in 31 1/2 pairs B) 63 chromosomes in 21 sets of 3 C) 63 chromosomes, each with 3 sister chromatids D) 21 chromosome pairs and 21 unique chromosomes
B
17. During which stage of meiosis does the homologue separation occur? A. prophase I B. anaphase I C. telophase I D. prophase II E. anaphase II
B
19) Which of the following characteristics do homologous chromosomes exhibit? A) They carry information for different traits. B) They carry information for the same traits. C) They carry the same alleles. D) They align on the metaphase plate in meiosis II.
B
2) The two homologs of a pair move toward opposite poles of dividing cell during A) mitosis. B) meiosis I. C) meiosis II. D) fertilization.
B
2. Which of the following is NOT a difference between anaphase I and anaphase II? A. At the end of anaphase I, each chromosome is composed of two chromatids and at the end of anaphase II, sister chromatids have separated, becoming daughter chromosomes B. Anaphase I occurs in a haploid cell while anaphase II occurs in a diploid cell. C. Sister chromatids separate during anaphase II while homologous chromosomes separate during anaphase I. D. The cell undergoing anaphase II is genetically different from what it contained while undergoing anaphase I.
B
22) Which of the following statements correctly describes a karyotype? A) It is a display of all of the cell types in an organism. B) It is an organized image of a cell's chromosomes. C) It reveals the appearance of an organism. D) It is a display of a cell's mitotic stages.
B
28. There is a species of desert lizard where only females are known to exist-there are no males known. It is nevertheless necessary for two females to court and for one to assume the posture of a male to stimulate the female to produce eggs. No fertilization can occur, and the eggs develop into female lizards. What is the probable evolutionary mechanism for this occurring? A. The species is probably going extinct. B. The desert is relatively uniform and there is little advantage to maintaining variation, but the animal has not been able to completely evolve away from its heritage of sexual reproduction. C. This switch in mating behavior is the direct physical reflection of crossing-over. D. This is probably an asexual organism attempting to mimic sexual reproduction.
B
29) Which of the following processes occurs in meiosis but not in mitosis? A) chromosome replication B) synapsis of chromosomes C) alignment of chromosomes at the equator D) condensation of chromosomes
B
29. In human females, when is meiosis II completed? A. at ovulation B. immediately after the sperm penetration of the secondary oocyte C. immediately after the sperm penetrates the primary oocyte D. None of the choices are correct.
B
3) Asexual reproduction occurs during which of the following processes? A) meiosis B) mitosis C) fertilization D) the exchange of chromosomes between organisms of different species
B
41) Somatic cells of roundworms have four individual chromosomes per cell. How many chromosomes would you expect to find in an ovum from a roundworm? A) four B) two C) eight D) a diploid number
B
46) Crossing over of chromosomes normally takes place during which of the following processes? A) meiosis II B) meiosis I C) mitosis D) mitosis and meiosis II
B
47) Which of the following statements describes one characteristic of each chromosome in a cell during the entire process of meiosis I? A) Each chromosome is paired with a homologous chromosome. B) Each chromosome consists of two sister chromatids joined by a centromere. C) Each chromosome consists of a single strand of DNA. D) Each chromosome is joined with its homologous pair to form a synaptonemal complex.
B
48) During which of the following processes do homologous pairs of chromosomes align adjacent to one another at the metaphase plate of a cell? A) metaphase of mitosis B) metaphase I of meiosis C) telophase II of meiosis D) metaphase II of meiosis
B
5) Which of the following statements is correct in comparing sexual and asexual reproduction? A) Asexual reproduction, but not sexual reproduction, is characteristic of only plants and fungi. B) In sexual reproduction, individuals transmit half of their nuclear genes to each of their offspring. C) In asexual reproduction, offspring are produced by fertilization without meiosis. D) Asexual reproduction produces only haploid offspring.
B
6) At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype? A) prophase B) metaphase C) anaphase D) interphase
B
7. Another name for a tetrad is a/an A. homologue. B. bivalent. C. öocyte. D. gamete. E. polar body.
B
8) Eukaryotic sexual life cycles show tremendous variation. Which of the following characteristics do all sexual life cycles have in common? I. Alternation of generations II. Meiosis III. Fertilization IV. Gametes V. Spores A) I, II, and IV B) II, III, and IV C) II, IV, and V D) I, II, III, IV, and V
B
9) Which of the following processes occurs in a plant's sexual life cycle? A) sporophytes produce gametes by meiosis B) gametophytes produce gametes by mitosis C) gametophytes produce gametes by meiosis D) sporophytes produce gametes by mitosis
B
10. Homologous chromosomes are similar in all of these characteristics EXCEPT A. similar in size. B. carry the same alleles for all traits. C. carry genes for the same traits. D. similar in shape and location of the centromere.
B Homologous chromosomes are similar in size, carry genes for the same traits, and are similar in shape and centromere location. They may carry different alleles for a trait.
26. Species X reproduces asexually by fission and species Y reproduces sexually. Consider that all other relevant characteristics are similar between these species. When the environment changes, then A. species X and Y will have an equal chance of surviving. B. species Y should have a better chance of surviving than species X. C. species X should have a better chance of surviving than species Y. D. neither species should have an advantage in surviving since organisms often become extinct when the environment changes.
B The value of sexual reproduction is the resulting genetic variation, which provides a species with a greater potential for survival in changing environments.
1. Which of the following is the correct sequence of the development of a mature sperm cell? A. Spermatid->spermatocyte->spermatogonium-> 2°spermatocyte->spermatozoan B. Spermatogonium-» 1°spermatocyte-> 2°spermatocyte-» spermatid -> spermatozoan C. Spermatozoan-» 1°spermatocyte-» 2°spermatocyte->spermatogonium ->spermatid D. Spermatogonium-» 1°spermatocyte-» 2°spermatocyte->spermatozoan ->spermatid
B Diploid cells called spermatogonia differentiate into primary spermatocytes, which undergo the first meiotic division to yield two haploid secondary spermatocytes. These undergo a second meiotic division to become immature spermatids. The spermatids then undergo a series of changes leading to the production of mature sperm, or spermatozoa.
9. What is the last point in the meiotic cycle in which the cell has a diploid number of chromosomes? A. During interphase B. During telophase I C. During interkinesis D. During telophase II
B The first meiotic division (reductional division) separates homologous chromosomes to opposite poles of the cell during anaphase I. Near the end of telophase I, cytokinesis occurs, resulting in two haploid (n) daughter cells. Thus, during interkinesis and anaphase II, the daughter cells are already haploid, eliminating choices (C) and (D). The cell is diploid during interphase, choice (A), but remains diploid up until the end of telophase I.
1) If a horticulturist breeding gardenias succeeds in having a single plant with a particularly desirable set of traits, which of the following would be her most probable and efficient route to establishing a line of such plants? A) Backtrack through her previous experiments to obtain another plant with the same traits. B) Breed this plant with another plant with much weaker traits. C) Clone the plant. D) Force the plant to self-pollinate to obtain an identical one.
C
14) In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosomes of the pair have in common? A) length and position of the centromere only B) length, centromere position, and staining pattern only C) length, centromere position, staining pattern, and traits coded for by their genes D) They have nothing in common except that they are X-shaped.
C
16. At which stage of meiosis is each chromosome composed of a single chromatid? A. prophase I B. metaphase II C. anaphase II D. prophase II E. metaphase I
C
18. Which statement is NOT true about homologues in meiosis I? A. Homologous chromosomes pair to form a tetrad. B. Homologous chromosomes separate and go to different daughter cells. C. Each homologue's centromere splits to form two chromosomes. D. Homologues exchange genetic material between non-sister chromatids. E. Homologues interact with the spindle as if they were one chromosome.
C
19. The genus Lacerta is composed of a species of lizards that are female and do not mate. They undergo "endomitosis" where one extra chromosome replication results in a tetraploid cell before meiosis begins. Normal female 2n offspring result without fertilization. What change(s) from regular meiosis (in preparation for fertilization) would be required to produce this system? A. The haploid cell products of meiosis II fuse. B. Meiosis stops after meiosis I and does not proceed to meiosis II. C. Cytokinesis does not follow "endomitosis" that results in a tetraploid cell. D. During anaphase II, the sister centromeres fail to separate and daughter cells will not form. E. During anaphase II, the daughter chromosomes are non-disjunctive and are all pulled to one daughter cell.
C
20. Interkinesis is different from interphase in which way? A. Interkinesis occurs after a cell finishes a nuclear division. B. Interkinesis is the stage that precedes a prophase stage. C. Interphase involves DNA replication and interkinesis does not. D. Interkinesis can be variable in length.
C
21) Which of the following statements is correct regarding the human X chromosomes? A) It is present in every somatic cell of males and females. B) It is the same size as other chromosomes and has the same number of genes. C) It carries genes that determine an individual's biological sex. D) It is referred to as an autosome.
C
22. Meiosis occurs during all of the following EXCEPT A. gametogenesis. B. oogenesis. C. pangenesis. D. spermatogenesis. Meiosis occurs during gametogenesis, oogenesis, and spermatogenesis.
C
23. The polar body is A. another name for an egg cell. B. a precursor cell that becomes an egg cell. C. a nonfunctional cell rudiment formed at the same time as an egg cell. D. the cell produced when fertilization occurs.
C
24) The somatic cells of a privet shrub each contain a total of 46 chromosomes. How do the chromosomes of this plant differ from the chromosomes of humans, who also have a total of 46? A) Privet shrub cells cannot reproduce sexually. B) Privet shrub sex cells have chromosomes that can synapse with human chromosomes in the laboratory. C) Genes of privet shrub chromosomes are significantly different than those in humans. D) Privet shrubs must be metabolically more like animals than like other shrubs.
C
26) How do cells at the completion of meiosis compare with cells that are in prophase of meiosis I? A) The cells have half the number of chromosomes and half the amount of DNA. B) The cells have the same number of chromosomes and half the amount of DNA. C) The cells have half the number of chromosomes and one-fourth the amount of DNA. D) The cells have half the amount of cytoplasm and twice the amount of DNA.
C
27. Before the time of Gregor Mendel and genetics, sexual reproduction was thought to produce a blending or equal mixing of the parents' traits. Today we know that A. offspring will be identical to one another and demonstrate traits exactly halfway between the parents' traits. B. offspring can vary from receiving over 99% of one parent's genes to receiving over 99% of the other parent's genes. C. offspring inherit essentially 50% of their genes from each parent, but two sibling offspring may share with each other from zero to 23 chromosomes in common from each parent, and further variation may occur due to crossing-over. D. offspring inherit copies of the same 23 pair of chromosomes from each of their parents but the rate of crossing-over makes them very dissimilar. E. there is one chance in 23 of getting identical sets of chromosomes from one parent, times two because there are two parents; therefore, two siblings out of every 46 are really identical except for crossing-over.
C
3. It could be said that males are able to provide gametes with more genetic diversity than females for reproduction. One main reason would be A. males provide more genes in sperm than females provide in eggs. B. crossing over occurs more often in the formation of sperm than in eggs. C. spermatogenesis in males results in four functional sperm while oogenesis in females results in only one egg and three structures that contain genetic information that is lost when they disintegrate. D. sperm that contain a recombination of genes are usually more successful in fertilizing an egg.
C
30) When chiasmata can first be seen in cells using a microscope, which of the following processes has most likely occurred? A) meiosis II B) anaphase II C) prophase I D) the separation of homologs
C
4. The cell formed through fertilization of an egg by a sperm is called a/an A. gamete. B. sperm cell. C. zygote. D. egg cell. E. ovum.
C
42) Which of the following processes occur during meiosis but not mitosis? A) Haploid cells fuse to form diploid cells. B) Haploid cells multiply into more haploid cells. C) Diploid cells form haploid cells. D) A diploid cell combines with a haploid cell.
C
44) Which of the following statements describes a major difference between meiosis II and mitosis in a diploid animal? A) Homologous chromosomes align on the metaphase plate in meiosis II. B) Sister chromatids separate in mitosis, and homologous chromosomes separate in meiosis II. C) Meiosis II occurs in a haploid cell, while mitosis occurs in diploid cells. D) Crossing over of chromosomes takes place in meiosis II.
C
49) During which of the following phases of meiosis do centromeres split and sister chromatids migrate to opposite poles of the cell? A) anaphase I B) telophase I C) anaphase II D) telophase II
C
53) Which of the following processes occurs when homologous chromosomes cross over in meiosis I? A) Two sister chromatids get tangled, resulting in one re-sequencing its DNA. B) Two sister chromatids exchange identical pieces of DNA. C) Corresponding segments of non-sister chromatids are exchanged. D) Maternal alleles are "corrected" to be like paternal alleles and vice versa.
C
55) The bulldog ant has a diploid number of two chromosomes. Therefore, following meiosis, each daughter cell will have a single chromosome. In addition to mutations, how might genetic diversity be generated in this species? A) crossing over only B) independent assortment only C) crossing over and random fertilization D) nothing else
C
56) Which of the following processes facilitates the fastest way for organisms to adapt to a changing environment? A) mutation B) asexual reproduction C) sexual reproduction D) mitosis
C
58) In eukaryotes, genetic information is passed to the next generation by processes that include mitosis or meiosis. Which of the following explanations correctly identifies the process and supports the claim that heritable information is passed from one generation to another? A) During mitosis, DNA replication occurs twice within the cell cycle to insure a full set of chromosomes within each of the daughter cells produced. B) Mitosis, followed by cytokinesis, produces daughter cells that are genetically different from the parent cell, thus insuring variation within the population. C) In asexual reproduction, a single individual is the sole parent and passes copies of its genes to its offspring without the fusion of gametes. D) Single-celled organisms can fuse their cells, reproducing asexually through mitosis to form new cells that are not identical to the parent cell.
C
7) Which of the following statements is true of a species that has a chromosome number of 2n = 16? A) The species is diploid with 32 chromosomes per cell. B) The species has 16 sets of chromosomes per cell. C) Each diploid cell has eight homologous pairs of chromosomes. D) A gamete from this species has four chromosomes
C
8. If a cell contains 12 chromosomes at the end of meiosis I, how many chromosomes will the daughter cells contain at the end of meiosis II? A. 3 B. 6 C. 12 D. 24
C
5. Certain ovarian tumors called granulosa cell tumors are known to produce excessive levels of estrogen. A physician who diagnoses a granulosa cell tumor should look for a secondary cancer in which of the following parts of the reproductive tract? A. Fallopian tube B. Cervix C. Endometrium D. Vagina
C Estrogen is known to cause growth of the endometrial lining during the follicular phase of the menstrual cycle, and its levels stay high during the luteal phase to promote vascularization and glandularization of this tissue. Excessive levels of estrogen may provide a strong enough signal for cell growth to promote tumor formation, or even cancer. The other tissues listed in this question require estrogen for development, but are not strongly associated with rapid tissue growth due to estrogen.
2. Which of the following correctly pairs the stage of development of an egg cell with.the relevant point in a woman's life cycle? A. From birth to menarche-prophase II B. At ovulation-metaphase I C. At ovulation-metaphase II D. At fertilization-prophase II
C From the time of birth until shortly before ovulation, all egg cells are arrested at the prophase stage of meiosis I. These cells are referred to as primary oocytes. At ovulation, the egg cell has completed meiosis I and is now arrested in met- aphase II as a haploid cell called a secondary oocyte. When a sperm penetrates the outer layers of the secondary oocyte, it completes meiosis II to become a mature ovum.
13. An individual who is phenotypically female is found to have only one copy of a disease-carrying recessive allele on the X chromosome, yet she demonstrates all of the classic symptoms of the disease. Geneticists determine she has a genotype that likely arose from nondisjunction in one of her parents. What is the likely genotype of this individual? A. 46,XX (46 chromosomes, with XX for sex chromosomes) B. 46,XY C. 45,X D. 47,XXY
C Nondisjunction refers to the incorrect segregation of homologous chromosomes during anaphase I, or of sister chroma- tids during anaphase II. In either case, one daughter cell ends up with two copies of related genetic material, while the other receives zero. Immediately, this should eliminate choices (A) and (B), which show a normal complement of chromosomes (46). An individual who has only one recessive disease-carrying allele, and yet still expresses the disease, likely does not have a dominant allele for the given trait. This is seen in males, who are hemizygous for many X-linked genes, and can also be seen in women with Turner syndrome (45,X), who have only one X chromosome. Thus, choice (C) is the answer.
6. Upon ovulation, the oocyte is released into the: A. fallopian tube. B. follicle. C. abdominal cavity. D. uterus.
C This subtle point about ovulation eludes most students and remains hard to believe until the organs are examined in anatomy class in medical school. The ruptured ovarian follicle releases an oocyte into the abdominal cavity, close to the entrance of the fallopian tube. With the aid of beating cilia, the oocyte is drawn into the fallopian tube, through which it travels until it reaches the uterus. If it is fertilized in the fallopian tube, it will implant in the uterine wall. If fertilization does not occur, it will be expelled along with the uterine lining during menstruation.
11) A particular organism has 46 chromosomes in its karyotype. Which of the following statements is correct regarding this organism? A) It must be human. B) It must be an animal. C) It reproduces sexually. D) It produces gametes with 23 chromosomes.
D
12. The overall function of meiosis includes all of the following EXCEPT A. gamete production. B. reduction of chromosome number (from 2N to N). C. providing genetic variation in sexually reproducing organisms. D. growth of the overall individual.
D
13. Sources of genetic variation in a sexually reproducing population include(s) which of the following? A. crossing over in Prophase I of meiosis B. independent assortment in Metaphase I of meiosis C. fertilization D. All of the choices are sources of genetic variation. E. None of the choices are sources of genetic variation.
D
14. To what does the term chiasma refer? A. the process of fertilization B. the life cycle of a fungus C. the process of crossing-over D. a structure that holds together homologues during crossing-over E. the period between meiosis I and meiosis II
D
2) Which of the following statements defines a genome? A) the complete set of an organism's polypeptides B) the complete set of a species' polypeptides C) a karyotype D) the complete set of an organism's genes and other DNA sequences
D
20) Many organisms spend most of their life cycle in the diploid state. If meiosis produces haploid cells, how is the diploid number restored for these types of organisms? A) by DNA replication B) through the transcription of DNA to RNA C) by synapsis of the homologous pairs of chromosomes during prophase of meiosis I D) by fertilization
D
24. Why do polar bodies form? A. They nurse the egg as it leaves the follicle. B. This is extra chromosomal material representing the X chromosome in each female cell. C. They orient the sperm toward the egg. D. They allow a reduction in chromosomes while preserving most of the cytoplasm for one egg. E. They orient the egg for penetration by the sperm. Polar bodies are a way to dispose of extra chromosomes while preserving most of the cytoplasm for one egg.
D
25) Which of the following statements describes the chromosomal makeup of each daughter cell after telophase of meiosis I? A) The cells are diploid, and the chromosomes are each composed of a single chromatid. B) The cells are diploid, and the chromosomes are each composed of two chromatids. C) The cells are haploid, and the chromosomes are each composed of a single chromatid. D) The cells are haploid, and the chromosomes are each composed of two chromatids.
D
28) During which of the following processes do sister chromatids separate from each other? A) during meiosis I only B) during meiosis II only C) during both mitosis and meiosis I D) during both mitosis and meiosis II
D
30. Where in the human male does spermatogenesis occur? A. ovaries B. prostate gland C. epididymis D. testes
D
33. All of the following are true concerning Down Syndrome EXCEPT A. it is caused by autosomal trisomy 21. B. in 23% of cases, the sperm contributes the extra chromosome. C. it is the most common trisomy in humans. D. chances of a woman having a child with Down Syndrome decreases with her age.
D
4) Quaking aspen trees can send out underground stems for asexual reproduction. Sexual reproduction is not as common, but when it does happen, the haploid gametes have 19 chromosomes. How many chromosomes are in the cells of the underground stems? A) 9 B) 10 C) 19 D) 38
D
40) A female with a paternal set of one orange and one long gene chromosome and a maternal set comprised of one blue and one short gene chromosome would be expected to produce which of the following types of eggs after meiosis? A) All eggs will have maternal types of gene combinations. B) All eggs will have paternal types of gene combinations. C) Half the eggs will have maternal and half will have paternal combinations. D) Each egg has a one-fourth chance of having either blue long, blue short, orange long, or orange short combinations.
D
43) During which of the following phases of meiosis do homologous chromosomes separate? A) anaphase II B) prophase I C) mitosis D) anaphase I
D
5. If a sperm cell contains 8 chromosomes, it comes from an animal that has ______ chromosomes. A. 4 B. 8 C. 12 D. 16 E. 24
D
51) For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes based on the independent assortment of chromosomes during meiosis? A) 23 B) 46 C) about 1,000 D) about 8 million
D
59) Genetic variation leads to genetic diversity in populations and is the raw material for evolution. Biological systems have multiple processes, such as reproduction, that affect genetic variation. They are evolutionarily conserved and shared by various organisms. Which of the following statements best represents the connection between reproduction and evolution? A) Plants that use sexual reproduction are rare since this type of reproduction in plants does not contribute to genetic diversity. B) In order to increase genetic diversity for evolution in sexually reproducing organisms, mutations must occur in the zygote after fertilization. C) Since prokaryotic organisms reproduce asexually, there is no mechanism for them to add genetic diversity for evolution. D) Sexual reproduction increases genetic variation because random mutations can be shuffled between organisms.
D
12. Which of the following is true regarding prophase? A. The chromosomes separate and move to opposite poles of the cell. B. The spindle apparatus disappears. C. The chromosomes uncoil. D. The nucleoli disappear.
D In prophase, the chromatin condenses into chromosomes, the spindle apparatus forms, and the nucleoli and nuclear membrane disappear. Choice (A) describes anaphase, whereas choices (B) and (C) describe telophase.
11. Which of the following statements correctly identifies a key difference between mitosis and meiosis? A. In metaphase of mitosis, replicated chromosomes line up in single file; in metaphase II of meiosis, replicated chromosomes line up on opposite sides of the metaphase plate. B. During anaphase of mitosis, homologous chromo- somes separate; during anaphase of meiosis I, sister chromatids separate. C. At the end of telophase of mitosis, the daughter cells are identical to each other; at the end of meiosis I, the daughter cells are identical to the parent cell. D. During metaphase of mitosis, centromeres are present directly on the metaphase plate; during metaphase of meiosis I, there are no centro meres on the metaphase plate.
D The key differences between mitosis and meiosis primarily appear during meiosis I. Of note, synapsis and crossing over occurs during prophase I, and homologous chromosomes are separated during meiosis I (rather than sister chromatids, as in mitosis). While the location of the centromeres relative to the metaphase plate may seem a trivial point, it is representative of the fact that homologous chromosomes line up on opposite sides of the equatorial plate in meiosis, in contrast to the alignment of each chromosome directly upon the metaphase plate in mitosis.
7. Cancer cells are cells in which mitosis occurs continuously, without regard to quality or quantity of the cells produced. For this reason, most chemotherapies attack rapidly dividing cells. At which point(s) in the cell cycle could chemotherapy effectively prevent cancer cell division? I. S stage II. Prophase III. Metaphase A. I only B. I and II only C. II and III only D. I, II, and III
D The question is asking us to determine at which points in the cell cycle we can prevent or at least lower the number of cells undergoing mitosis. One idea would be to prevent DNA synthesis during the S stage of the cell cycle. Without the DNA being replicated, two viable daughter cells could not be formed. Another idea would be preventing the mitotic cycle from occurring altogether in prophase by preventing spindle apparatus formation, preventing the nuclear membrane from dissolving, or other processes during this phase. Similarly, a treatment that would act on cells in the metaphase stage of the cell cycle would also interfere with the mitotic cycle. Therefore, any of the three solutions presented would be a viable option.
10. Which of the following does NOT likely contribute to genetic variability? A. Random fertilization of an egg by a sperm B. Random segregation of homologous chromosomes C. Crossing over between homologous chromosomes during meiosis D. Replication of the DNA during S stage
D The safest way to answer this question correctly is to go through each answer choice and eliminate tl'ie ones that con- tribute to genetic variability. The random fertilization of an egg by a sperm, the random segregation of homologous chro- mosomes during anaphase I, and crossing over between homologous chromosomes during prophase I all contribute to genetic variability during sexual reproduction because they result in novel combinations of genetic material, eliminating choices (A), (B), and (C). S stage, choice (D), should specifically not cause increased genetic variability; the DNA should be copied precisely, without error, meaning that both strands of DNA should be identical.
4. A researcher wishes to incorporate a radio labeled deoxyadenine into the genome of one of the two daughter cells that would arise as a result of mitosis. What is the latest stage of cellular development during which the radiolabeled deoxyadenine could be added to achieve this result? A. G1 B. G2 C. M D. S
D To ensure that the labeled deoxyadenine will be incorporated into the DNA of one of the daughter cells, we have to insert the nucleotide before DNA replication has been completed. Because replication occurs during S stage, we could introduce the deoxyadenine during G1 or S stage. Because G1 precedes S, the latest point the deoxyadenine could be added is the S stage.
15. During which stage of meiosis are the bivalents arranged along the equator? A. prophase I B. metaphase II C. anaphase II D. prophase II E. metaphase I
E
25. Which of the following is/are true about sexual reproduction? A. At the cellular level is the opposite of reproduction since it involves two cells fusing to become one. B. It requires the development of organs such as the uterus, which are of no immediate survival advantage to the individual but are advantageous to the species. C. It regularly produces a wider array of adaptations to the external environment in a shorter period of time. D. It regularly produces a wider array of adaptations to the internal environment (disease agents, parasites) in a shorter period of time. E. All of the choices are true.
E
31. Which is NOT true about daughter cells of mitosis or meiosis? A. In meiosis, daughter cells are haploid. B. In meiosis, there are four daughter cells. C. In mitosis, there are two daughter cells. D. In mitosis, the daughter cells are genetically identical. E. In meiosis, the daughter cells are genetically identical.
E
50. A lattice holds the members of a bivalent together in such a way that the RNA of the non-sister chromatids is aligned. T or F ?
F A lattice holds the members of a bivalent together in such a way that the DNA, not RNA, of the non-sister chromatids is aligned.
38. Primary nondisjunction occurs during meiosis II when the sister chromatids fail to separate and both daughter chromosomes go in the same gamete. T or F ?
F Primary nondisjunction occurs during meiosis I when both members of a homologous pair go into the same daughter cell.
36. A change in the chromosome number resulting from nondisjunction is called euploidy. T or F ?
F A change in the chromosome number resulting from nondisjunction is called aneuploidy.
53. Only one of the four daughter cells becomes a functional gamete in spermatogenesis. T or F ?
F It is not true that only one of the four daughter cells becomes a functional gamete in spermatogenesis. All are functional.
49. Oogenesis always involves an equal division of cell contents in the formation of an egg and polar bodies. T or F ?
F Oogenesis does not involve an equal division of cell contents. The two cells formed are the secondary oocyte, which receives almost all the cytoplasm and a polar body, which is much smaller.
35. The correct number of chromosomes in a species is known as aneuploidy. T or F ?
F The correct number of chromosomes in a species is known as euploidy.
45. At a cellular level, sexual reproduction involves the fusion of two cells into one. Some biologists have proposed early conditions (such as life in a pool that is drying up) that could have promoted primitive cells trying to engulf members of their own species but they succeeded in only fusing together. That means that the real evolutionary question may be the following: How could these early cells reduce the chromosome number by half? Consider the stages in mitotic division. Which processes in both nuclear replication and division, and cytokinesis, would need to be turned on or turned off in order to move from mitosis to meiosis?
In meiosis, during prophase I bivalents form and then crossing over occurs. These events do not occur in mitosis. During metaphase I the bivalents independently align and then separate during anaphase. At this time the number of chromosomes are reduced by half. Cytokinesis occurs. Meiosis II occurs in order to separate sister chromatids. Cytokinesis occurs again near the end of meiosis II. In mitosis, each chromosome aligns along the metaphase plate and then sister chromatids separate during anaphase. Cytokinesis occurs near the end of the process.
37. Monosomy occurs when an individual has only one of a particular type of chromosome. T or F ?
T
39. Sex chromosome aneuploids are better tolerated and have a better chance of producing survivors. T or F ?
T
43. Extra copies of sex chromosomes are more easily tolerated in humans than extra copies of autosomes. T or F ?
T
51. It is estimated that an average of two or three cross-overs occur per human chromosome. T or F ?
T
52. Aneuploidy is a change in the number of chromosomes resulting from nondisjunction during meiosis. T or F ?
T
54. Jacobs Syndrome, XYY, results from nondisjunction during spermatogenesis. T or F ?
T
41. Some plants are tetraploid (4n). How might such a plant arise?
Tetraploidy could result from a 2n zygote not dividing after replicating its chromosomes, thereby becoming 4n. All cells formed thereafter, by normal mitotic divisions, will have four sets of chromosomes.
6. If gametes had the same number of chromosomes as body cells, and an organism had 12 chromosomes in its body cells, how many chromosomes would it have after three generations? How does this illustrate the necessity of meiosis for gamete formation?
The number of chromosomes would double each generation. After three generations, the organisms would have 96 chromosomes. Meiosis, also known as reduction division, produces gametes with half the number of chromosomes (1n) as the parent cell (2n) from which it comes. As two haploid gametes combine during fertilization to form a diploid (2n) zygote, the number of chromosomes for each species is maintained from generation to generation.
1. What does meiosis do? a. It produces haploid cells from diploid cells. b. It produces diploid cells from haploid cells. c. It reproduces a diploid set of chromosomes. d. It fuses an egg cell with a sperm cell.
a
12. Meiosis II is similar to mitosis because a. sister chromatids separate. b. homologous chromosomes line up indepen- dently on the metaphase plate. c. DNA replication precedes the division. d. nonsister chromatids separate when cohesins at the centromeres are cleaved.
a
6. A reduction in the number of chromosomes per cell occurs a. during meiosis 1. b. during meiosis II. c. during mitosis. d. during the S phase of interphase.
a
Which of the following is a key difference be- tween mitosis and meiosis? a. Only in mitosis are daughter cells genetically identical to the parent cell. b. Sister chromatids separate during mitosis but not meiosis. c. DNA synthesis does not occur prior to meiosis d. Only mitosis has a metaphase.
a
15. Which of the following is not true of homologous chromosomes? a. They behave independently in mitosis. b. They are joined in synapsis during the S phase of meiosis. c. They are held together during synapsis by a synaptonemal complex. d. Crossing over between nonsister chromatids of homologous chromosomes is indicated by the presence of chiasmata.
b
16. Which of the following statements is not true? a. Sister chromatid cohesion at areas where cross- ing over has occurred holds homologous chro- mosomes together until anaphase I. b. Recombinant chromosomes are produced when both maternal and paternal chromo- somes independently assort into the same gamete. c. In mitosis, separation of sister chromatids in anaphase results in two identical cells. d. Separation of sister chromatids in anaphase II does not usually result in two identical cells.
b
20. Which of the following is least likely to be a source of genetic variation in sexually reproduc- ing organisms? a. crossing over b. replication of DNA during S phase before meiosis I c. independent assortment of chromosomes d. random fertilization of gametes
b
3. Homologous chromosomes a. have identical DNA sequences in their genes. b. have genes for the same characters at the same loci. c. are found in gametes containing X chromosomes but not in those containing a Y chromosome. d. separate in meiosis II.
b
5. What is a karyotype? a. a genotype of an individual b. a pictorial display of an individual's chromosomes c. a unique combination of chromosomes found in a gamete d. a species-specific diploid number of chromosomes
b
7. In most fungi and some protists, a. gametes are formed by meiosis. b. the organism is haploid and may be multicel- lular or unicellular. c. the gametophyte generation produces gametes by mitosis. d. reproduction is exclusively asexual.
b
8. In the alternation of generations found in plants, a. the sporophyte generation produces spores by mitosis. b. the gametophyte generation produces gametes by mitosis. c. the zygote develops into a sporophyte genera- tion by meiosis. d. spores develop into the haploid sporophyte generation.
b
17. In a species with a diploid number of 6, how many different combinations of maternal and paternal chromosomes would be possible in gametes? a. 6 b. 8 c. 12 d. 64
b Diploid of 6 = 3 pairs Answer is 2 to the power of 3 = 8
11. Compared with one of the four cells produced by meiosis, a cell in G2 before meiosis has a. twice as much DNA and twice as many chromosomes . b. twice as much DNA but the same number of chromosomes. c. four times as much DNA and twice as many chromosomes. d. four times as much DNA and four times as many chromosomes.
c
13. The Texan nine-banded armadillo (Dasypus novemcinctus) has a diploid chromosome number of 64 (i.e., 2n = 64). How many chromatids would be found in an armadillo cell in prophase I of meiosis? a. 32 b.64 c. 128 d. You can't tell based on this information.
c
22. What is the evolutionary significance of bdelloid rotifers, which have not engaged in sex in 40 mil- lion years? a. They show that asexual reproduction is more advantageous because it ensures that successful combinations of alleles are passed to offspring. b. Although their 400 species originated through sexual reproduction, each species has success- fully cloned itself since it arose. c. They exchange genetic material through horizontal gene transfer while in a state of suspended animation during dry periods, sup- porting the idea that genetic variation is evolu- tionarily advantageous. d. Their long history shows that sexual reproduc- tion and genetic variation are not required for evolutionary success.
c
4. Which of the following represents a clone? a. a group of seedlings produced by seeds from the same tree b. you and your brother c. the cuttings from your spider plant that you gave to six of your friends d. the litter of new kittens that you're tryu;g to give away.
c
18. In a sexually reproducing species with a diploid number of 8, how many different combinations of chromosomes would be possible in the diploid offspring? a. 16 c. 256 b. 64 d. 512
c Diploid of 8 = 4 pairs The offspring have 2 to the power of 4 for the sperm and 2 to the power of 4 for the egg so the number of combinations is 2 to the power of 4 times 2 to the power of 4 (16 x 16 = 256). The number of possible combinations of maternal and paternal chromosomes is 2^n, 2 to the power of n, where n is the haploid number
A cell has 12 chromosomes at the end of mitosis. How many chromosomes would it have in the G2 phase of its next cell cycle? a) 6 b) 9 c) 12 d) 24
c) 12 Each chromosome consists of two sister chromatids and thus even though it has 24 sister chromatids, it still has only 12 chromosomes when you want to count CHROMOSOMES, count the number of CENTROMERES to give you the number of CHROMOSOMES. Even though, they have 2 sister chromatids, they are attached to a SINGLE CENTROMERE, which means its considered to be ONE chromosome.
10. During meiosis I, a. homologous chromosomes separate, reducing the chromosome number by half. b. crossing over between nonsister chromatids occurs. c. paternal and maternal chromosomes assort randomly. d. all of the above occur.
d
19. The calculation of offspring in question 18 in- cludes only variation resulting from a. crossing over. b. random fertilization. c. independent assortment of chromosomes. d. both band c.
d
2. Asexual reproduction of a diploid organism a. is impossible because the chromosome number would double each generation. b. usually involves spores produced by meiosis. c. produces variation among sibling offspring. d. produces offspring identical to each other and the parent.
d
21. Which of the following statements describes why or how recombinant chromosomes add to genetic variability? a. They are formed as a result of random fertiliza- tion when two sets of chromosomes combine in a zygote. b. They randomly orient during metaphase II, and the nonequivalent sister chromatids sepa- rate in anaphase II. c. Genetic material from two parents is combined on the same chromosome. d. Both band c are true.
d
9. A synaptonemal complex would be found during a. early prophase of mitosis. b. the fusion of gametes in fertilization. c. metaphase I of meiosis. d. early prophase of meiosis I.
d