Genetics Chap 2 Homework – Flashcards
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Part A
Which list of steps in the eukaryotic cell cycle is given in the correct order? (step order listed left to right)
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*. . . G1 - S - G2 - M - G1 . . .
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Haploid cells do not undergo mitosis
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False
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Each of the following events occurs during mitosis except _______
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This describes the role of kinetochore microtubules during anaphase. Polar microtubules lengthen during anaphase, causing the cell to become elliptical.
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Separation of sister chromatids occurs _______.
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at anaphase in mitosis and anaphase II in meiosis
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The end result of meiosis is four haploid daughter cells.
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true
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Novel combinations of genes can arise from _______.
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reciprocal exchange of DNA between homologs during prophase I
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What is the arrangement of chromosomes during metaphase of mitosis?
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Sister chromatids align along the equatorial plane of the cell.
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When do sister chromatids separate during meiosis?
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anaphase II
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The "folded-fiber model" is a model of what structure?
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metaphase chromosomes
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If one follows 160 primary oocytes in an animal through their various stages of oogenesis, how many secondary oocytes would be formed?
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160
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How many first polar bodies would be formed?
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160
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How many ootids would be formed?
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160
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If one follows 160 primary spermatocytes in an animal through their various stages of spermatogenesis, how many secondary spermatocytes would be formed?
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320
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How many spermatids would be formed?
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640
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After meiosis I, assuming no crossing over, what combinations of chromosomes are possible in the two product cells? Select all that apply.
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Am, Bm, Cp
Ap, Bm, Cp
Ap, Bp, Cp
Ap, Bm, Cm
Ap, Bp, Cm
Am, Bm, Cm
Am, Bp, Cm
Am, Bp, Cp
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How many different combinations of chromatids are possible during the early phases of anaphase in meiosis II?
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4
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Contrast the end results of meiosis with those of mitosis.
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In mitosis, there is no change in chromosome number or kind in the two daughter cells, whereas in meiosis, numerous potentially different haploid cells are produced.
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Contrast the genetic content and the origin of sister versus nonsister chromatids during their earliest appearance in prophase I of meiosis.
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Sister chromatids are genetically identical, except where mutations may have occurred during DNA replication. Nonsister chromatids are genetically similar if on homologous chromosomes and genetically dissimilar if on nonhomologous chromosomes.
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How might the genetic content of these change by the time tetrads have aligned at the metaphase plate during metaphase I of meiosis?
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If crossing over occurs, then chromatids attached to the same centromere may no longer be identical.
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A diploid cell contains three pairs of homologous chromosomes designated C1 and C2, M1 and M2, and S1 and S2; no crossing over occurs. What possible combinations of chromosomes will be present in DAUGHTER CELLS FOLLOWING MEIOSIS
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C1/C2, M1/M2, S1/S2
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--THE FIRST MEIOTIC METAPHASE?
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C1/C2, M1/M2, S1/S2
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--HAPLOID CELLS FOLLOWING BOTH DIVISIONS OF MEIOSIS?
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C2, M2, S1
C2, M1, S1
C2, M1, S2
C1, M1, S1
C2, M2, S2
C1, M2, S1
C1, M2, S2
C1, M1, S2
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Contrast the chromatin fiber with the mitotic chromosome.
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In the chromatin fiber, DNA is uncoiled and uncondensed, whereas in the mitotic chromosome, it is coiled and condensed.
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How are the two structures related?
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The transition from chromatin to individual chromosomes occurs at the beginning of mitosis (or meiosis). During this time, chromatin fibers fold up and condense into the typical mitotic chromosome.
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Which of the following are chromatid pairs that will be present during metaphase in mitosis?
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AmAm
BmBm
BpBp
CmCm
ApAp
CpCp
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Which type of cell structure is the nucleolus organizer (NOR) responsible for producing?
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Ribosome
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Which of the following cell structures is directly involved in protein synthesis?
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rough endoplasmic reticulum and ribosomes
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Given that each G1 nucleus from this organism contains 16 picograms of DNA, how many picograms of chromosomal DNA would you expect in the cell shown above?
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16 picograms of DNA
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A __________ chromosome has its centromere located very close to, but not on, the end of the chromosome.
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acrocentric
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During interphase of the cell cycle, ________.
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DNA content essentially doubles
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The house fly, Musca domestica, has a haploid chromosome number of 6. How many chromatids should be present in a diploid, somatic, metaphase cell?
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24
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S phase is the part of interphase when DNA duplication takes place.
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true
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The centromere of a chromosome separates during anaphase.
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true
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A chromosome may contain one or two chromatids in different phases of the mitotic or meiotic cell cycle.
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true
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If a typical somatic cell has 64 chromosomes, how many chromosomes are expected in each gamete of that organism?
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32
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In an organism with 52 chromosomes, how many bivalents would be expected to form during meiosis?
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26
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What is the outcome of synapsis, a significant event in meiosis?
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side-by-side alignment of homologous chromosomes
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The horse (Equus caballus) has 32 pairs of chromosomes, whereas the donkey (Equus asinus) has 31 pairs of chromosomes. How many chromosomes would be expected in the somatic tissue of a mule?
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63
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During meiosis, chromosome number reduction takes place in anaphase II.
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false
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The meiotic cell cycle involves two cell divisions but only one DNA replication.
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true
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An organism with a haploid number of 10 will produce 1024 combinations of chromosomes at the end of meiosis.
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true
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Cells that are metabolically active, but not destined to proliferate are said to be in __________.
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G0 phase
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In a healthy male, how many sperm cells would be expected to form from (a) 400 primary spermatocytes? (b) 400 secondary spermatocytes?
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(a) 1600; (b) 800
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In a healthy female, how many secondary oocytes would be expected to form from 100 primary oocytes? How many first polar bodies would be expected from 100 primary oocytes?
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100;100
