Meiosis

Question 1

What are diploid cells?

Answer 1

Cells which contain two sets of chromosomes (one from mum, one from dad)
- normal body cells

Question 2

What are haploid cells?

Answer 2

Cells which contain only one single copy of each chromosomes
- gametes

Question 3

What occurs in meiosis I?

Answer 3

Splitting up of the homologous pairs of chromosomes

Question 4

What happens in meiosis II?

Answer 4

Splitting up of the identical sister chromatids

Question 5

What are the 2 ways meiosis brings about genetic variation?

Answer 5

• Crossing over (late P1)
• Independent segregation of homologous chromosomes (M1)

Question 6

What is crossing over?

Answer 6

Chromatids of homologous pairs exchange equivalent sections of DNA

Question 7

Define synapsis

Answer 7

The process of a homologous pair of chromosomes coming together

Question 8

Define bivalent

Answer 8

Formed when the homologous pair comes together and lines up base for base, ready for crossing over

Question 9

Define chiasmata

Answer 9

The point at which the homologous pairs cross over

Question 10

How does independent segregation lead to genetic variation?

Answer 10

Homologous pairs line up randomly, producing new genetic combinations of maternal and paternal alleles

Question 11

What is the equation for the number of possible combinations resulting from independent segregation?

Answer 11

2^n where n = number of pairs of homologous chromosomes