MITOSIS/MEIOSIS REVIEW
1 What is the rhythmic change in cyclin concentration in a cell cycle due to Its destruction by an enzyme phosphorylated by MPF.
2A cell that passes the restriction point will most likely undergo chromosome duplication.
3 Which of the following organisms does not reproduce cells by mitosis? bacterium B Cytokinesis often, but not always, follows mitosis. If cells undergo mitosis and not cytokinesis, this would result in cell structures with two or more nuclei.
4 If there are 12 chromosomes in an animal cell in G1 stage of the cell cycle, what is the diploid number of chromosomes for this organism? 12
5 Regarding mitosis and cytokinesis, one difference between higher plants and animals is that in plants . a cell plate begins to form at telophase, whereas in animals a cleavage furrow is initiated at that stage.
6 How do the daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it was in G1 of the cell cycle? The daughter cells have the same number of chromosomes and the same amount of DNA. C Cells that have stopped dividing and are differentiating are in the G1 phase of the cell cycle.
Answer the question(s) below that consist of five numbered headings concerned with the cell cycle. For each phrase or sentence, select the heading that is most closely related to it. Each heading may be used once, more than once, or not at all. 1. G0 2. G1 3. S 4. G2 5. M
7 The "restriction point" occurs here. 2
8 Nerve and muscle cells are in this phase. 1
9 The shortest part of the cycle. 5
10 Chromosomes are duplicated during this phase 3
11 Cyclin is destroyed toward the end of this phase. 5
12 The formation of a cell plate is beginning across the middle of a cell and nuclei are reforming at opposite ends of the cell. What kind of a cell is this? a plant cell undergoing cytokinesis
Refer to the terms below to answer the following question(s). Each term may be used once, more than once, or not at all. 1. telophase 2. anaphase 3. interphase 4. metaphase 5. prophase
13 DNA replication takes place. 3
14 Centrioles begin to move apart in animal cells. 5
15 This is the longest of the mitotic stages 5
16 Centromeres uncouple, sister chromatids are separated, and each new chromosome moves to opposite poles of the cell. b
17 The centromere is a region in which chromatids are attached to one another.
18 When is a chromatid a chromatid? A chromatid is a chromatid as long as it is held in association with a sister chromatid at the centromere.
19 All of the following are characteristic of telophase of mitosis/ Cytokinesis begins. /The nuclear envelope reappears. /. Chromosomes begin to condense together. / Astral microtubules disappear.
20 A cell containing 92 chromatids at the start of mitosis would, at its completion, produce cells containing how many chromosomes?46
21 During which phase of mitosis are two-chromatid chromosomes found? from G2 of interphase through metaphase
22 If there are 20 centromeres in a cell, how many chromosomes are there? 20
23 All of the following occur during the latter stages of mitotic prophase/ centrioles move apart. / nucleolus disintegrates./ nuclear envelope disappears. / spindle is organized.
24 If there are twelve centromeres in a cell in G1 of the cell cycle, what is the diploid number of chromosomes? 12
25 If the haploid number for a species is 3, each dividing diploid cell will have how many chromatids at metaphase? 12
26 All of the following occur during mitosis/ the coiling of chromosomes. /the division of centromeres. /the formation of a spindle. / the degradation of the nuclear envelope.
27 How many chromosomes will a cell have during mitotic anaphase if the diploid chromosome number is 4? 8
28 Suppose a plant cell had a mutation that prevented the Golgi apparatus from functioning. Which of the following processes would occur? /. cellular respiration /. photosynthesis / mitosis /. DNA replication
29 The phases of meiosis that cause the most variation in the four resulting daughter cells are prophase I and anaphase I
30 If the liver cells of an organism have 24 chromosomes, the sperm cells would have how many chromosomes? 12
31 How does the sexual life cycle increase the genetic variation in a species?
1. by producing gametes with different combinations of parental chromosomes
2. by allowing the combination of chromosomes from two different individuals
3. by allowing recombination of alleles on a chromosome
32 Which of the following events occurs during prophase I of meiosis? synapsis and crossing over
33 Which of the following is true of a species that has a chromosome number of 2n = 16? A gamete from this species has 8 chromosomes.
34 At which stage of mitosis are chromosomes photographed in the preparation of a karyotype? metaphase
35 Any genetic differences in a clone are due to which process? mutation
36 Which of the following occur in comparing prophase I of meiosis and prophase of mitosis? / The chromosomes condense in both. / The nuclear envelope disassembles in both. / A spindle forms in both./ Each chromosome has two chromatids.
37 How do cells at the completion of meiosis compare with the cell from which they were derived?
They have half the number of chromosomes and half the amount of DNA.
38 What is a karyotype? a method of organizing the homologous chromosomes of a cell in relation to their number, size, and type
39What is a human cell that contains 22 pairs of autosomes and two X chromosomes? a female somatic cell
40 For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes? more than 8 million
41 Crossing over occurs during which phase of meiosis? prophase I Use the key shown below to answer the following question(s). Each answer may be used once, more than once, or not at all.
1. If the statement is true for mitosis only
2. If the statement is true for meiosis I only
3. If the statement is true for meiosis II only
4. If the statement is true for mitosis and meiosis I
5. If the statement is true for mitosis and meiosis II
42 Homologous chromosomes synapse and crossing over occurs. 2
43 This occurs when a cell divides to form two cells that are genetically identical.1E Centromeres uncouple and chromatids are separated from each other.5
44 Independent assortment of chromosomes occurs.2
Match the key event of meiosis with the stages listed below, to answer the following question(s).
I. Prophase I VI. Prophase II
II. Metaphase I VII. Metaphase II
III. Anaphase I VIII. Anaphase II
IV. Telophase I IX. Telophase II
V. Interkinesis
45 Tetrads of chromosomes align at the metaphase plate; independent assortment soon follows. II
46 Synapsis of homologous pairs occurs; crossing over may occur.I
47 Nuclear envelopes may form; no replication of chromosomes takes place.V
48 Centromeres of sister chromatids uncouple and chromatids separateVII
49 All of the following are functions of meiosis in plants / production of spores. /reduction of chromosome number in half. /independent assortment of chromosomes. / crossing over and recombination of homologs.
50 This question refers to some essential steps in meiosis described below.
1. Formation of two new nuclei, each with half the chromosomes present in the parental nucleus 5
2. Tetrads align at the metaphase plat e2
3. Separation of sister chromatids 4
4. Separation of the homologs; no uncoupling of the centromere 3
5. Synapsis; chromosomes moving to the middle of the cell in pairs 1
51 After telophase I of meiosis, what is the chromosomal make-up of each daughter cell?
haploid, and the chromosomes are composed of two chromatids