6.3 - Meiosis Flashcards
1
Q
What is meiosis?
A
- a form of cell division that gives rise to genetic variation
2
Q
What is the main role of meiosis?
A
- production of haploid gametes
3
Q
What do cells produced from meiosis contain?
A
- half the number of chromosomes
4
Q
What is seen in the four cells produced by meiosis?
A
- genetic differences between all four of them
5
Q
How is genetic variation achieved in meiosis?
A
- crossing over of chromosomes = pairs of chromosomes line up and exchange some of their genetic material
- independent assortment of chromosomes = there are various combinations of chromosome arrangement
6
Q
What does meiosis produce and what from?
A
- four haploid gametes
- from a diploid cell
7
Q
How many phases are there in meiosis?
A
- two
8
Q
What are the names of the two phases?
A
- meiosis I
- meiosis II
9
Q
What happens in meiosis I?
A
- homologous chromosomes separate therefore
there is only one chromosome of every pair per gamete
10
Q
What happens in meiosis II?
A
- the sister chromatids separate
11
Q
What are the stages of meiosis I?
A
- prophase I
- metaphase I
- anaphase I
- telophase I
12
Q
What is different between prophase in mitosis and meiosis?
A
- synapsis
- crossing over of homologous chromosomes (at chiasmata) which allow the genetic variation to occur
13
Q
How does metaphase lead to variation?
A
- chromosomes are aligned on the equator through random assortment
14
Q
What happens in anaphase I?
A
- the homologous chromosomes separate
15
Q
What happens in telophase I?
A
- the nuclear envelope reforms around haploid nuclei containing half the number of chromosomes
