Bio Exam 2

What is the ploidy of a 2n animal cell that is in Prophase I?

2n

The formation of ova, or female reproductive cells, occurs when diploid germ cells undergo meiosis. In female swamp wallabies, diploid germ cells contain 10 chromosomes. At the beginning of meiosis I, a female wallaby germ cells contains

5 homologous pairs of chromosomes comprising a total of 20 chromatids

A cell with a diploid number 2n=8 has how many pairs of homologous chromosomes?

8

Which of the following is true of crossing over? A. Segments of DNA are traded between unrelated chromosomes. B. Crossing over occurs more often in male gametes than female gametes. C. Most homologue pairs do not have any crossover events D. A chiasma indicates that a crossover has occurred.

A chiasma indicates that a crossover has occurred.

In an animal cell, individual sister chromatids are being pulled to opposite poles by spindle fibers. What stage you are observing? a. Anaphase b. Anaphase I c. Anaphase II

Anaphase Anaphase II

When does crossing over occur in meiosis?

Prophase 1

Which of the following best explains how the random alignment of homologous chromosomes during meiosis helps generate varied offspring? A. Random alignment increases the likelihood of crossing over between non-sister chromatids B. Random alignment results in the formation of gametes that contain different numbers of chromosomes C. Random alignment results in the formation of some diploid and some haploid gametes D. Random alignment increases the number of possible chromosome combinations in the gametes

Random alignment increases the number of possible chromosome combinations in the gametes

Of the following events that occur during meiosis, which contributes most to genetic diversity in the human population? a. Recombination between homologous chromatids during meiosis I b. Condensation of chromatin during meiosis 1 c. Alignment of sister chromatids at the metaphase plate during meiosis II d. Separation of sister chromatids during meiosis II

Recombination between homologous chromatids during meiosis I

Which of the following correctly describes how mitosis and meiosis are similar? A. Sister chromatids segregate to opposite poles of the cell during both mitosis and meiosis. B. Crossing over occurs between homologous chromatids during both mitosis and meiosis. C. Both mitosis and meiosis produce diploid daughter cells. D. Both mitosis and meiosis produce genetically identical daughter cells.

Sister chromatids segregate to opposite poles of the cell during both mitosis and meiosis.

DNA wound around histones makes structures called ____ which are separated by regions of ______ DNA a. nucleosome, single-stranded b. beads, telomere c. telomeres, single-stranded d. nucleosome, linker e. chromatin, linker

a. nucleosome, single-stranded

Genes G and H are linked. Through which of the following processes can new combinations of G and H alleles be generated? I. Independent assortment II. Nondisjunction III. Segregation IV. Crossing over

crossing over

A cell with 20 chromosomes enters into meiosis. How many chromosomes are in each daughter cell after the completion of meiosis I? a. 5 b. 10 c. 20

10

Researchers have developed a drug which inhibits homologous pairing of chromosomes in certain cells. Which of the following statements describe the effect? a. Only cells undergoing mitosis will be affected by this drug b. Cells undergoing either mitosis or meiosis will be affected by this drug c. Metaphase I and Metaphase II will be normal in these cells d. Disjunction will occur normally in these cells e. Crossing over will not occur in these cells

Crossing over will not occur in these cells

Place the steps of binary fission in the correct order: I. Origin of replication moves to the other side of the cell II. Replication finishes III. Chromosome replication begins IV. The cell divides into two daughter cells V. The plasma membrane is pinched inward

III - I - II - V - IV

Arrange the following in order form smallest to largest: I. histone II. purine III. nucleosome IV. chromosome V. DNA strand

III - IV - I - V - II

Which of the following correctly describes meiosis? a. Meiosis begins with a diploid parent cell and ends with two diploid daughter cells. b. Meiosis begins with a haploid parent cell and ends with two haploid daughter cells. c. Meiosis begins with a haploid parent cell and ends with four haploid daughter cells. d. Meiosis begins with a diploid parent cell and ends with four haploid daughter cells.

Meiosis begins with a diploid parent cell and ends with four haploid daughter cells.

Which of the following correctly describes how meiosis I and meiosis II differ? A. Genetic material is exchanged between homologous chromatids during meiosis II but not meiosis I. B. Cytokinesis occurs following meiosis II but not meiosis I C. Pairs of homologous chromosomes are separated during meiosis I, while sister chromatids are separated during meiosis II D. Meiosis I produce diploid daughter cells, while meiosis II produces haploid daughter cells.

Pairs of homologous chromosomes are separated during meiosis I, while sister chromatids are separated during meiosis II

Which of the following correctly describes the number of chromosomes in the daughter cells produced during gametogenesis in fruit flies? A. The daughter cells each contain eight chromosomes after meiosis I and eight chromosomes after meiosis II. B. The daughter cells each contain four chromosomes after meiosis I and four chromosomes after meiosis II. C. The daughter cells each contain four chromosomes after meiosis I and two chromosomes after meiosis II. D. The daughter cells each contain eight chromosomes after meiosis I and four chromosomes after meiosis II

The daughter cells each contain four chromosomes after meiosis I and four chromosomes after meiosis II.