Question 1

Independent assortment of chromosomes is a result of

Accepted Answer

the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I.

Question 2

Assume that an organism exists in which crossing over does not occur, but that all other processes associated with meiosis occur normally. Consider how the absence of crossing over would affect the outcome of meiosis.If crossing over did not occur, which of the following statements about meiosis would be true?

Accepted Answer

There would be less genetic variation among gametes.

Question 3

What is the best evidence telling you whether this cell is diploid or haploid?

Accepted Answer

The cell is diploid because it contains two sets of chromosomes.Only diploid cells contain two sets of chromosomes, one maternal and one paternal. Read about diploid cells.

Question 4

Homologous chromosomes move toward opposite poles of a dividing cell during

Accepted Answer

meiosis I

Question 5

Which of the following defines a genome?

Accepted Answer

the complete set of an organism's genes

Question 6

Which of the following occurs during meiosis but not during mitosis?

Accepted Answer

Synapsis occurs.The pairing of homologous chromosomes that only occurs during prophase I of meiosis is called synapsis.

Question 7

If a cell has completed the first meiotic division and is just beginning meiosis II, which of the following is an appropriate description of its contents?

Accepted Answer

It has half the amount of DNA as the cell that began meiosis.

Question 8

Which of the following happens at the conclusion of meiosis I?

Accepted Answer

Homologous chromosomes of a pair are separated from each other.

Question 9

When we see chiasmata under a microscope, that lets us know which of the following has occurred?

Accepted Answer

prophase I

Question 10

The following question refers to the essential steps in meiosis described below.1. Formation of four new nuclei, each with half the chromosomes present in the parental nucleus2. Alignment of tetrads at the metaphase plate3. Separation of sister chromatids4. Separation of the homologs; no uncoupling of the centromere5. Synapsis; chromosomes moving to the middle of the cell in pairsWhich of the steps takes place in both mitosis and meiosis?

Accepted Answer

3

Question 11

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 would be

Accepted Answer

2x

Question 12

How many different combinations of maternal and paternal chromosomes can be packaged in gametes made by an organism with a diploid number of 8 (2n = 8)?

Accepted Answer

16

Question 13

Meiosis II is similar to mitosis in that

Accepted Answer

sister chromatids separate during anaphase.

Question 14

Asexual reproduction _____.

Accepted Answer

produces offspring genetically identical to the parentOnly one individual makes a genetic contribution to the offspring.

Question 15

How are sister chromatids and homologous chromosomes different from each other?

Accepted Answer

Homologous chromosomes contain the same gene loci but may have different alleles of a particular gene. Sister chromatids are identical copies of each other produced during DNA replication.One homologous chromosome comes from the father, and the other comes from the mother. Sister chromatids are identical copies of each other.

Question 16

Which of the following is true of a species that has a chromosome number of 2n = 16?

Accepted Answer

Each cell has eight homologous pairs.

Question 17

Which of the following might result in a human zygote with 45 chromosomes?

Accepted Answer

an error in either egg or sperm meiotic anaphase

Question 18

The parent cell that enters meiosis is diploid, whereas the four daughter cells that result are haploid.Which statement correctly describes how cellular DNA content and ploidy levels change during meiosis I and meiosis II?

Accepted Answer

DNA content is halved in both meiosis I and meiosis II. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis II.During anaphase of both meiosis I and meiosis II, the DNA content (number of copies of chromosomes) in a cell is halved. However, the ploidy level changes only when the number of unique chromosome sets in the cell changes. This occurs only in meiosis I (where separation of homologous chromosomes decreases the ploidy level from 2n to n and produces daughter cells with a single chromosome set).

Question 19

Meiosis I produces _____ cells, each of which is _____.

Accepted Answer

two ... haploidAt the end of meiosis I there are two haploid cells.

Question 20

Meiosis II typically produces _____ cells, each of which is _____.

Accepted Answer

four ... haploidAt the end of meiosis II there are typically 4 haploid cells.

Question 21

prophase II

Accepted Answer

The events of prophase II are essentially the same as those of mitotic prophase except that prophase II cells are haploid.

Question 22

anaphase II

Accepted Answer

During anaphase II sister chromatids separate and migrate to opposite poles.

Question 23

telophase II and cytokinesis

Accepted Answer

Four haploid cells are present at the end of telophase II and cytokinesis.

Question 24

During _____ sister chromatids separate.

Accepted Answer

anaphase IIAnaphase II is essentially the same as mitotic anaphase except that the cell is haploid.

Question 25

telophase I and cytokinesis

Accepted Answer

At the end of telophase I and cytokinesis there are two haploid cells.

Question 26

At the end of _____ and cytokinesis, haploid cells contain chromosomes that each consist of two sister chromatids.

Accepted Answer

telophase IAt the end of telophase I and cytokinesis, there are two haploid cells with chromosomes that consist of two sister chromatids each.

Question 27

prophase I

Accepted Answer

Homologous chromosomes pair during prophase I

Question 28

metaphase II

Accepted Answer

Metaphase II is essentially the same as mitotic metaphase except that the cells are haploid.

Question 29

metaphase I

Accepted Answer

During metaphase I tetrads align along the metaphase plate.

Question 30

Synapsis occurs during _____.

Accepted Answer

prophase ISynapsis, the pairing of homologous chromosomes, occurs during prophase I.

Question 31

Homologous chromosomes migrate to opposite poles during _____.

Accepted Answer

anaphase IDuring anaphase I sister chromatids remain attached at their centromeres, and homologous chromosomes move to opposite poles.

Question 32

During _____ chromosomes align single file along the equator of a haploid cell.

Accepted Answer

metaphase IIMetaphase II is essentially the same as mitotic metaphase except that the cell is haploid.

Question 33

anaphase I

Accepted Answer

During anaphase I homologous chromosomes, consisting of sister chromatids, migrate to opposite poles.

Question 34

At the end of _____ and cytokinesis there are four haploid cells.

Accepted Answer

telophase IIAt the end of telophase II and cytokinesis there are four haploid cells.

Question 35

During _____ a spindle forms in a haploid cell.

Accepted Answer

prophase IIProphase II is essentially the same as mitotic prophase except that the cells are haploid.

Question 36

interphase

Accepted Answer

During interphase the centrosome duplicates and the chromosomes are not condensed.

Question 37

Mitosis goes on continuously in most parts of the body, whereas meiosis takes place only in the _____.

Accepted Answer

gonads

Question 38

Meiosis I is the only time that chromosomes line up by _____ pairs.

Accepted Answer

homologous

Question 39

The _____ is the point of attachment between two duplicated chromosomes.

Accepted Answer

centromere

Question 40

We can see that the chromosomes are duplicated and lined up by homologous pair. That only happens at the start of _____.

Accepted Answer

meiosis I

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