Chapter 4.2: Meiosis

Question 1

what happens during prophase I? (3)

Answer 1

1. each pair homologous chromosomes pair side by side
2. homologous chromosomes are held tightly together along their lengths
3. exchanging of genetic info may occur

Question 2

which stage does synapsis occur in?

Answer 2

prophase I

Question 3

crossing over occurs in this stage…

Answer 3

prophase I

Question 4

what happens during metaphase I? (2)

Answer 4

1. pairs of homologous chromosomes line up along the equator of the cell
2. spindle fibres attach to each centromere of each homologous chromosome

Question 5

what happens during anaphase I? (3)

Answer 5

1. homologous chromosomes separate and move to opposite poles of the cell
2. sister chromatids are still held together, therefore centromeres do not split as they do in mitosis
3. a single chromosome from each homologous pair moves to each pole of the cell

Question 6

what happens during telophase I? (3)

Answer 6

1. homologous chromosomes begin to uncoil, spindle fibres disappear
2. cytokinesis takes place
3. two haploid cell are formed

Question 7

homologous chromosomes pair up at the equator during this stage…

Answer 7

metaphase I

Question 8

sister chromatids are separated from each other during…

Answer 8

anaphase II

Question 9

four new daughter cells are produced at the end of this stage…

Answer 9

telophase II

Question 10

what are the two outcomes of meiosis?

Answer 10

genetic reduction: produces daughter cells with half the number of chromosomes as the parent cell
genetic recombination: products have different combinations of alleles

Question 11

when does independent assortment occur?

Answer 11

metaphase I

Question 12

what is crossing over?

Answer 12

when non-sister chromatids exchange pieces of information, hence increasing genetic diversity

Question 13

when can non-disjunction occur? why?

Answer 13

anaphase I or II, chromatids do not separate to the poles as they should

Question 14

what disease can be caused by deletion of a section of a chromosome?

Answer 14

Cri Du Chat

Question 15

what disease can be caused by duplication of a section of a chromosome?

Answer 15

Charlot-Marie Tooth Disease

Question 16

what disease can be caused by inversion of a section of a chromosome?

Answer 16

FG Syndrome

Question 17

what disease can be caused by transloaction of a section of a chromosome?

Answer 17

Chronic Myelogenous Lukemia