Chapter 13 Mastering

What number and types of chromosomes are found in a human somatic cell?

44 autosomes and 2 sex chromosomes

A human cell containing 22 autosomes and a Y chromosome is

a sperm

Which of the following statements about reproduction is correct?

In sexual reproduction, individuals transmit half of their nuclear genes to each of their offspring.

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

Each diploid cell has eight homologous pairs of chromosomes.

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

two ... haploid

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

four ... haploid

During _____ sister chromatids separate.

anaphase II

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

telophase I

Synapsis occurs during _____.

Prophase I

Homologous chromosomes migrate to opposite poles during _____.

anaphase I

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

metaphase II

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

telophase II

During _____ a spindle forms in a haploid cell.

Prophase II

Mitosis can occur in both haploid and diploid cells, but meiosis can only occur in diploid cells. Why?

Meiosis produces daughter cells with half the number of chromosome sets of the parent cell; therefore, the parent cell must be diploid.

The second division of meiosis reduces the number of chromosomes in each cell by half

false

In meiosis II, the daughter cells from meiosis I undergo a very similar division to mitosis

true

Crossing over and synapsis occur after the homologous chromosomes separate in meiosis I

false

The first division of meiosis reduces the number of chromosomes in each cell by half.

true

Meiosis occurs in both somatic (body) cells and sex cells.

false

Which of the following statements correctly describes how sister chromatids and homologous chromosomes differ from each other?

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.

In a typical animal, mitosis produces _________, while meiosis produces____________.

two diploid daughter cells, four haploid daughter cells

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

synapsis occurs

Meiosis II is similar to mitosis in that

sister chromatids separate during anaphase

A cell has completed meiosis I and the first cytokinesis, and is just beginning meiosis II. Which of the following statements describes its genetic contents?

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

Which of the following statements describes the chromosomal makeup of each daughter cell after telophase of meiosis I?

The cells are haploid, and the chromosomes are each composed of two chromatids.

How do cells at the completion of meiosis compare with cells that are in prophase of meiosis I?

The cells have half the number of chromosomes and one-fourth the amount of DNA.

Haploid cells form containing joined sister chromatids.

VIII

Cohesins at centromeres of sister chromatids breakdown.

Anaphase II

Homologous chromosomes are aligned at the middle of the spindle.

Metaphase I

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?

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.