4.3: Genetic diversity - Mutation or Meiosis

Question 1

Key features of meiosis

Answer 1

1) Produces 4 genetically different cells
2) Two nuclear divisions
3) Divides diploid (2n) into haploid (n)

Question 2

Describe crossing over (4)

Answer 2

1) Homologous chromosomes associate and bivalent is formed
2) Chiasmata form - chromosomes entangle and twist
3) Equal length of non-sister chromatids are exchanged
4) Producing a new combination of alleles

Question 3

When does crossing over happen?

Answer 3

During prophase and metaphase of meiosis 1

Question 4

Describe independent segregation

Answer 4

When homologous chromosomes attach to spindle vibes and pair up side by side and can be reshuffled in any combination

Question 5

When does independent segregation happen?

Answer 5

During metaphase I

Question 6

How do you calculate the number of different pairs of homologous chromosomes?

Answer 6

2^n. n = number of different pairs of homologous chromosomes

Question 7

How does fertilisation increase variation?

Answer 7

Random which sperm and egg will fuse in fertilisation

Question 8

What is non-disjunction

Answer 8

When chromosomes or chromatids don’t split equally during anaphase

Question 9

What is an inversion mutation?

Answer 9

Segment of bases reversed end to end

Question 10

What is duplication mutation?

Answer 10

Doubling part or entire of the chromosome

Question 11

What are translocation mutations

Answer 11

When groups of base pairs relocate from one area of genome to the other between non-homologous chromosomes