Biology - Chapter 11

Human gametes are produced by _____.

Meiosis produces haploid gametes from a diploid parental cell.

A diploid organism whose somatic (nonsex) cells each contain 32 chromosomes produces gametes containing _____ chromosomes.

16

Normal human gametes carry _____ chromosomes.

23. This is the number of chromosomes in a single set of human chromosomes.

Which of these cells is (are) haploid?

C and D Once meiosis I is completed, cells are haploid.

describe 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. Submit

True or False? Crossing over prevents homologous chromosomes from separating during meiosis I.

False

Heredity and genetic variation

In organisms that reproduce sexually, the processes of DNA replication, the precise pairing of homologs during crossing over, chromosome alignment and separation in meiosis I and II, and fertilization ensure that traits pass from one generation to the next.

If crossing over did not occur, which of the following statements about meiosis would be true? Select all that apply.

There would be less genetic variation among gametes.

True or False? As a result of crossing over, sister chromatids are no longer identical to each other.

True

True or False? Crossing over occurs at the ends of chromosomes, rather than near the centromeres.

True

True or False? For crossing over to occur, homologous chromosomes must align precisely early in prophase I so that nonsister chromatids can exchange corresponding segments of DNA.

True