Meiosis

Question 1

What is meiosis?

Answer 1

A specialised form of cell division to produce gametes in sexually reproducing organisms

Question 2

What are gametes?

Answer 2

Reproductive cells that arise from germline cells and contain half of the genetic material of a somatic cell

Question 3

What is a zygote?

Answer 3

A diploid cell formed by a combination of two haploid gamete cells

Question 4

What are the two distinct cellular divisions?

Answer 4

1. Meiosis I - which separated each homologous chromosome into two different cells
2. Meiosis II - which separates each sister chromatid into four different cells

Question 5

What is the result of meiosis(end of cytokinesis)?

Answer 5

4 genetically unique gamete cells (n)

Question 6

What is interphase?

Answer 6

G1, S(Synthesis), G2

There the cells grow and duplicates all of its chromosomes in preparation for division

Question 7

What is Prophase I?

Answer 7

The nuclear membrane breaks down as chromosomes condense and line up in homologous pairs. Crossing over may occur

Question 8

What is Crossing Over?

Answer 8

The exchange of genetic material between non-sister chromatids during Prophase I of meiosis, resulting in new combinations of alleles in daughter cells

Question 9

What is Metaphase I?

Answer 9

Homologous chromosomes will then line up randomly on opposite sides of the metaphase plate, with one copy on either side. Each chromosome is then attached to microtubules of which ever pole it is closest to in preparation to be separated during the next stage

Question 10

What is the metaphase plate?

Answer 10

The equator of a dividing cell where chromosomes will line up during metaphase

Question 11

What are microtubules?

Answer 11

Long tube-like fibre proteins that form part of the cytoskeleton of a eukaryotic cell and help give the cell its structure.

Question 12

What is Independent Assortment?

Answer 12

Random orientation of homologous chromosomes along the metaphase plate during metaphase I

Question 13

What is Anaphase I?

Answer 13

The homologous chromosomes are moved apart towards opposite poles of the cell, but are still two chromatids attached at the centre

Question 14

What is Telophase I?

Answer 14

The chromosomes arrive at opposite ends of the cell as the nuclear membrane is cleaved, in preparation for cytokinesis

Question 15

Why is crossing over important for genetic diversity?

Answer 15

Crossing over results in the formation of new recombinant chromatids each with its own unique combination of alleles. Genes that will be inherited are no longer identical

Question 16

Why is independent assortment important for genetic diversity?

Answer 16

As it is randomised, there can be multiple combinations of genes in the gametes

Question 17

What is Prophase II?

Answer 17

The two cells prepare for another division, and the nuclear envelope begins to break down

Question 18

What is Metaphase II?

Answer 18

Each combination lines up along the metaphase plate of the cell, with microtubules prepare to pull the chromosomes apart

Question 19

What is Anaphase II?

Answer 19

Sister chromatids are now separated and pulled towards opposite poles

Question 20

What is Telophase II?

Answer 20

Separate nuclear membranes start to form around each cell as chromosomes begin to decondensed and unravel

Question 21

What is Cytokinesis?

Answer 21

Cytokinesis splits each chromosome sets at opposite ends of the cell into four new haploid cells (daughter cells)