Meiosis

Question 1

What does sexual reproduction involve?

Answer 1

Meiosis
Gamete production
Fertilization

Question 2

Describe prophase 1

Answer 2

Long and complex~90% of meiotic division
Synopsis occurs where homologous chromosomes pair together
Crossing over occurs between homologues at chiasmata

Question 3

What evidence of crossing over has there been?

Answer 3

Cross shaped figures as evidence of exchanges between paired chromosomes

Question 4

Describe metaphase 1

Answer 4

Chromosomes are on metaphase plate and are still in homologues pairs
Kinetochore microtubules attach to one chromosome of each pair

Question 5

Describe anaphase 1

Answer 5

Homologous chromosomes separate
Spindle pulls chromosomes to poles
Sister chromatids remain attached

Question 6

Describe telophase 1

Answer 6

Cytokinesis produces 2 daughter cells

No further replication of DNA before 2nd meiotic division

Question 7

Describe metaphase 2

Answer 7

Chromosomes of metaphase plate

Question 8

Describe anaphase 2

Answer 8

Centromeres separate and sister chromatids move away

Question 9

Describe telophase 2

Answer 9

Separate nuclei form
Cytokinesis occurs
4 haploid daughter cells

Question 10

Describe independent assortment of chromosomes

Answer 10

Orientation of homologous pairs on metaphase is random

Combinations possible during meiosis is 2^n

Question 11

Describe crossing over

Answer 11

Precise- gene by gene

Produces recombinant chromosomes which contain a mixture of genes from each parent

Question 12

How do sexual life cycles produce genetic variation?

Answer 12

Independent segregation
Crossing over
Random fertilization