Meiosis and Genetic Variation

Which of these events is an important factor in increasing variety among sexually reproducing organisms?

• crossing over

• gene linkage

• testcross

• mitosis

Which phrase best describes the process of meiosis?

• occurs in body cells

• produces haploid gametes

• happens only in haploid cells

• results in genetically identical cells

The exchange of segments of DNA between the members of a pair of chromosomes __________.

• is called genetic crossing

• always produces genetic disorders

• acts as a source of variations within a species

• ensures that variations within a species never occur

Which phrase best describes the process of crossing over?

• pairs of sister chromatids become linked

• Pairs of sister chromatids exchange segments.

• Pairs of homologous chromosomes become linked.

• Pairs of homologous chromosomes exchange segments.

How is gametogenesis different in females than in males?

• Males produce four functional sperm while females produce only one functional egg.

• Males produce only one functional sperm while females produce four functional eggs.

• Males produce four genetically identical sperm while females produce four genetically different eggs.

• Males produce four genetically different sperm while females produce four genetically identical eggs.

During which of these does the separation of homologous chromosomes occur?

• mitosis

• meiosis I

• meiosis II

• fertilization

What happens to chromosomes when crossing over takes place?

• decrease in number

• produce new genes

• mutate in the first division

• exchange corresponding segments of DNA

What happens to the sister chromatids in meiosis II?

• They duplicate

• They are separated

• They do not take part

• They remain together

In which phase of meiosis does the chromosome number change from diploid to haploid?

• prophase 1

• anaphase 1

• prophase 2

• anaphase 2

Which phrase best describes meiosis I?

• fusion of sister chromatids

• creation of two diploid cells

• duplication of paired chromosomes

• division of homologous chromosomes