Meiosis

Question 0

Prophase I

Answer 0

The chromosomes condense and crossing over may occur. Exchange of genetic material from the mother and father will result in a new combination of genes or variation in the gametes produced at the end of meiosis.

Question 1

Interphase I

Answer 1

Replication of the chromosomes occurs before the chromosomes become visible. Each homologous pair replicates to produce genetically identical chromatids joined at the centromere.

Question 2

Metaphase I

Answer 2

Homologous pairs line up along each side of the equator. This occurs at random therefore different arrangements are possible, resulting in variation between the gametes produced.

Question 3

Anaphase I

Answer 3

Contraction of the spindle fibres produced by the centrioles cause the homologous chromosomes to separate and be pulled to the opposite poles of the cell.

Question 4

Telophase I

Answer 4

The cell divides at the equator, producing two intermediate cells. Each cell contains two chromosomes, one from each of the homologous pairs.

Question 5

Prophase II

Answer 5

New spindles form and the chromosomes, each consisting of two chromatids joined at the centimetre, migrate towards the equator of the cell.

Question 6

Metaphase II

Answer 6

Chromosomes line up along the equator of the cell.

Question 7

Anaphase II

Answer 7

The chromatids are pulled apart by contraction of the spindle fibres and migrate to opposite poles of the cell.

Question 8

Telophase II

Answer 8

The cells divide at the equator to produce four gametes. Each gamete contains half the normal number of chromosomes from the original parent cell. (Haploid)

Question 9

Purpose of meiosis

Answer 9

Occurs in eukaryotes to produce four daughter cells with half the number of chromosomes (haploid). Occurs in testes and ovaries – collectively called the gonads.

Question 10

Difference between meiosis and mitosis

Answer 10

1. no crossing over in mitosis
2. chromosomes line up under each other in mitosis
3. chromosomes line up as homologous pairs in meiosis
4. crossing over occurs in meiosis

Question 11

Difference between meiosis and mitosis

Answer 11

1. no crossing over in mitosis
2. chromosomes line up under each other in mitosis
3. chromosomes line up as homologous pairs in meiosis
4. crossing over occurs in meiosis