Biology - Chapter 9 HW

Daughter cells produced in meiosis are identical.

FALSE

Germ cells are haploid but gametes are diploid.

FALSE

Mitosis and meiosis II are similar, except that cells undergoing meiosis II are diploid and cells undergoing mitosis are haploid.

FALSE

Only germ cells have sex chromosomes.

FALSE

Why is meiosis useful? Select all that apply.

It produces genetically variable offspring. It provides an alternate route to cell division for cells that fail to complete mitosis.

Daughter cells produced in meiosis have

half the number of chromosomes as the parent cell

Random orientation of homologous chromosomes occurs in ________ of meiosis.

metaphase I

Centromeres divide in

mitosis and meiosis II

In the experiment discussed in the Investigating Life feature, what variable was different between the tan bars and the red bars in the graph below?

presence of living bacteria

What statement correctly describes the result of the experiment discussed in the Investigating Life feature?

Sexual reproduction increased in roundworms exposed to live disease-causing bacteria.

Both somatic cells and germ cells are diploid, although only germ cells can undergo meiosis.

TRUE

Chromosome duplication occurs prior to both mitosis and meiosis.

TRUE

Crossing over allows the reassortment of parental combinations of alleles.

TRUE

Crossing over occurs during prophase I of meiosis.

TRUE

Meiosis produces four nonidentical cells, each containing neither homologous chromosomes nor sister chromatids.

TRUE

The gene shuffling that occurs during meiosis allows two parents to produce genetically diverse offspring.

TRUE

A crossover in meiosis is an exchange of genetic material between

sister chromatids of homologous chromosomes.

What evolutionary advantages explain why the rate of sexual reproduction increased in roundworms exposed to live disease-causing bacteria? Select all that apply.

New allele combinations were advantageous in the presence of parasites with high mutation and reproduction rates. Sexual reproduction increased genetic variability and survival in a changing environment.

Use the animation and your knowledge of crossing over to select the true statement.

No answer is correct.

Suppose that after the cell below undergoes meiosis I and meiosis II, the result is one gamete with two chromosomes, two gametes with three chromosomes, and one gamete with four chromosomes. What has occurred? (Click on the correct answer.)

Nondisjunction during meiosis II

Consider a cell that has three pairs of chromosomes. What are the chances that a gamete produced from this cell will contain only maternal chromosomes?

1/8

A cell that has four pairs of chromosomes is undergoing meiosis. What is the number of possible chromosome combinations in the gametes produced by that cell?

16

Arrange the following events in the proper order in which they occur during meiosis 1 = Separation of homologous chromosomes 2 = Coming together of homologous chromosomes 3 = Crossing-over 4 = Random orientation of homologous chromosomes at cell equator

2, 3, 4, 1

How are diploid cells, homologous chromosomes, and alleles related?

Diploid cells have homologous pairs of chromosomes, which carry the same genes as one another but not necessarily the same alleles.

How are "gamete," "chromosomes," and "zygote" related?

Gametes unite, forming zygotes with two sets of chromosomes.

Select all of the following that are true regarding nondisjunction and trisomy 21 (Down syndrome).

The older the mother, the higher than chances of producing a child with Down syndrome. Nondisjunction during sperm production can lead to sperm gametes with abnormal numbers of chromosomes.

Select all of the following that can result from nondisjunction of the X chromosome.

an XXX female Klinefelter syndrome Turner syndrome

The number of cells produced in meiosis is

twice the number of cells produced in mitosis.

If crossing over occurs only between the two alleles of the same gene, as shown in the animation, what allele combinations are present in the gametes?

two gametes with parental combinations of alleles, and two recombinant gametes