Meiosis

Question 1

What does each organisms have?

Answer 1

2 copies of each gene, one from the mother and one from the father.

Question 2

How are these genes carried?

Answer 2

On chromosomes.

Question 3

Genes are carried on Chromosomes. Therefore what does each nucleus contain?

Answer 3

A matching set of chromosomes-1 maternal and 1 paternal.

Question 4

What is this matching set known as?

Answer 4

Homologous pairs

Question 5

What is an allele?

Answer 5

A different version of the same gene.

Question 6

Why is Meiosis important?

Answer 6

-Production of Gametes
-Creating Variation

Question 7

What is the first stage in Meiosis?

Answer 7

-Prophase 1

Question 8

What happens in Prophase 1?

Answer 8

Like in Mitosis
-Chromosomes condense
-Nuclear envelope disintegrates, nucleolus disappears
-Spindle formation begins

Question 9

What do the homologous chromosomes form?

Answer 9

Pair up which form Bivalents

Question 10

What happens when these Bivalents form?

Answer 10

Crossing over occurs where genes from the same locus are swapped between the homologous pairs.

Question 11

Which function of meiosis does this carry out?

Answer 11

Variation

Question 12

What is the second stage in Meiosis?

Answer 12

Metaphase 1

Question 13

What happens in Metaphase 1?

Answer 13

Same as Metaphase in Mitosis EXCEPT the homologous pairs line up along the metaphase plate (equator) instead of individual chromosomes.

Question 14

What is the orientation of each homologous pair?

Answer 14

Random

Question 15

Which way do the paternal and maternal chromosomes face in this orientation?

Answer 15

They could face either pole.

Question 16

What is this random orientation and facing called?

Answer 16

Independent (random) assortment.

Question 17

What does Independent Assortment create?

Answer 17

Variation

Question 18

How is Anaphase 1 different from Anaphase in Mitosis?

Answer 18

The homologous chromosomes are pulled to opposite poles.
-Maternal chromatids stay together and Paternal chromatids stay together.

Question 19

What happens in Telophase 1?

Answer 19

Chromosomes assemble at each pole and uncoil.
Nuclear Membrane reforms.
(essentially the same as telophase in mitosis)

Question 20

What happens in Prophase 2?

Answer 20

-Each chromosome consists of 2 chromatids.
-The chromosomes condense, nuclear envelope disintegrates.
-Spindle formation begins.

Question 21

What happens in Metaphase 2?

Answer 21

-Individual chromosomes line up on Metaphase plate(equator),
-Independent assortment occurs again

Question 22

Why does the Independent assortment occur again?

Answer 22

The chromatids are no longer identical.

Question 23

What does this independent assortment create?

Answer 23

Creates more genetic variation.

Question 24

What happens in Anaphase 2?

Answer 24

Chromatids of individual chromosomes are pulled to opposite poles.

Question 25

What happens in Telophase 2?

Answer 25

-Chromatids at poles.
-Chromosomes uncoil to form chromatin again
-Nuclear envelope reforms
-Nucleus becomes visible.

Question 26

What are the chromatids now referred to in Telophase after they have assembles at the poles?

Answer 26

Chromosomes

Question 27

What happens in Cytokinesis?

Answer 27

Forms 4 genetically different daughter cells which are haploid due to the reduction division.

Question 28

What do the daughter cell becomes in cytokinesis?

Answer 28

Gametes