Unit 5: Heredity

Question 1

Phases of meiosis 1

Answer 1

Prophase, metaphase, anaphas, telophase and cytokinesis

Question 2

role of meiosis I

Answer 2

separates homologous chromosomes

Question 3

phases of meiosis II

Answer 3

the same as meiosis II

Question 4

role of meiosis II

Answer 4

separates sister chromatids

Question 5

Differences of meiosis I and II

Answer 5

Meiosis I includes crossing over or recombination of genetic material between chromosome pairs, while meiosis II does not.

Question 6

Meiosis I, Prophase I

Answer 6

Centrosome movement, spindle formation, and nuclear envelope breakdown is the same as mitosis.
In early Prophase I, each chromosome pairs with its homolog and “crossing over” occurs
“Chiasmata” = Regions where crossing over occurs
Late Prophase I, microtubules from the poles attach to kinetochores

Question 7

Metaphase I

Answer 7

Pairs of homologous chromosomes are aligned at metaphase plate
Each pair lines up independently of other pairs

Question 8

Anaphase I

Answer 8

Break of the protein cohesin
Homologs move towards poles of cell, guided by spindle apparatus
Sister chromatid cohesion persists

Question 9

Telophase I and Cytokinesis

Answer 9

Beginning in Telophase I, each half of cell has a complete haploid set of duplicated chromosomes
Cytokinesis occurs simultaneously to Telophase I
Animals: cleavage furrow
Some species: chromosomes decondense and nuclear envelope forms
No chromosome duplication occurs here

Question 10

Daughter cell resulting from mitosis are -

Answer 10

2 identical daughter cells

Question 11

Daughter cell resulting from meiosis are -

Answer 11

4 unique daughter cells

Question 12

Difference of mitosis and meiosis

Answer 12

• mitosis take place in somatic cell while meiosis occurs in reproductive gametes
• no crossing over in mitosis but there is crossing over in meiosis

Question 13

When do homologous chromosomes separate during meiosis

Answer 13

Anaphase I

Question 14

How do homologous chromosomes separate during anaphase

Answer 14

Homologs move towards poles of cell, guided by spindle apparatus
Sister chromatid cohesion persists

Question 15

how do daughter cells receive both maternal and paternal chromosomes

Answer 15

At anaphase one of each pair of chromosomes goes to each daughter cell, such that each daughter cell inherits one copy of the paternal chromosome, and one copy of the maternal chromosome

Question 16

What process occurs during meiosis I that causes daughter cells to be haploid

Answer 16

Cytokinesis

Question 17

What is crossing over?

Answer 17

the exchange of DNA between paired homologous chromosomes

Question 18

How does crossing over increase genetic diversity

Answer 18

the exchange of genetic information occurs. This exchange generates new groupings of genes.

Question 19

What is independent assortment

Answer 19

After crossing over, when aligned on the metaphase plate, each pair may orient themselves with either the maternal or paternal homolog closer to one pole
50% chance a particular daughter cell of meiosis I will get the maternal chromosome