6.3a - Meiosis

Question 1

Define gametes.

Answer 1

Haploid sex cells produced by meiosis in organisms that sexually reproduce.

Question 2

Define haploid.

Answer 2

1/2 the normal chromosome number (1 chromosome of each type)

Question 3

Define diploid.

Answer 3

Normal chromosome number - 2 of each type, one from each parent

Question 4

Define zygote.

Answer 4

Fertilised egg, initial diploid formed when 2 gametes fuse - earliest stage of embryonic development.

Question 5

How is each characteristic of an organism coded for?

Answer 5

By 2 copies of each gene per parent.

- Nucleus contains matching set of chromosomes

Question 6

Define homologous chromosomes.

Answer 6

Matching pair of chromosomes, one from each parent

- Each chromosome in a pair, has the same genes in the same location

Question 7

Define allele.

Answer 7

Gene variants, different versions of the same gene

Question 8

Why are homologous chromosomes the same length?

Answer 8

Because they have the same gene in the same position and centromeres in the same position.

Question 9

Define reduction division.

Answer 9

Cell division from diploid to haploid cell (meiosis 1)

Question 10

Give the brief stages of meiosis.

Answer 10

Meiosis 1:
- 1st division is reduction division, where homologous chromosomes separate to 2 new cells (intermediate cells have 1 full set of genes - diploid).

Meiosis 2:
- Chromatid pairs in daughter cells of meiosis 1 separate making 4 haploid cells in total.