6.2 Mitosis

Question 1

Why is mitosis important ?

Answer 1

Asexual reproduction : production of genetically identical offspring from one parent

Growth

Replacement and repair of tissues

Question 2

What is a chromatid?

Answer 2

When each DNA molecule ( chromosome ) is converted into two identical DNA molecules.

Question 3

What is a centromere ?

Answer 3

Where two chromatids are joined together.

Question 4

List the stages of mitosis in order?

Answer 4

Pour Me A Tea

```
interphase
Prophase
Metaphase
Anaphase
Telophase
( cytokinesis )
~~~

Question 5

What happens in prophase?

Answer 5

Chromosomes condense

Nuclear envelope disintegrates

Nucleolus is no longer visible / disappears

Centrioles move to opposite ends of cells / poles

Question 6

What happens in metaphase?

Answer 6

Chromosomes attached to spindle fibres at centromere

Chromosomes align at equator

Question 7

What happens in anaphase ?

Answer 7

Chromosomes move towards opposite poles

Spindle fibres change length / shorten, pulling chromatids apart

Question 8

What happens in telophase ?

Answer 8

As the new sister chromatids reach the poles of the cells

A new nuclear envelope forms around each set

The spindle breaks down

The chromosomes uncoil and are no longer visible under a microscope

Question 9

What happens in cytokinesis ?

Answer 9

Whole cell splits to form two new genetically identical cells

Question 10

How can you tell the difference between plant and animal cells in magnified images?

Answer 10

Animal : cleavage furrow forms. Cell surface membrane pulled inwards by cytoskeleton until it is close enough to fuse around the middle, forming two cells.

Plant : cleavage furrows can’t form because of cell wall. Vesicles assemble where metaphase plate was. Visible fuse with each other and the membrane, dividing into two.