Topic 2.3.2 - Mitosis

Question 1

When does mitosis take place?

Answer 1

Division of a zygote into a multicellular organism before birth
Growth of tissues during development into an adult
Replacement of damaged cells
Formation of clones of T and B cell clones.

Question 2

What does each chromosome consist of?

Answer 2

2 sister chromatids joined at the centromere

Question 3

Prophase.

Answer 3

Chromosomes coil up and become visible
Nucleolus breaks down and centrioles begin to pull apart to form the spindle.

Question 4

Metaphase.

Answer 4

Nuclear membrane has been broken down and centrioles are at opposite ends of the cell.
This forms a set of microtubules between known as the spindle
Chromatids line up along the equator
each centromere associated with a microtubule of the spindle

Question 5

Anaphase

Answer 5

Centromeres split meaning chromatids separate becoming chromosmes
Chromosomes pulled to opposite ends of the cell

Question 6

Telophase

Answer 6

Chromatids have reached poles of cell.
Referred to chromosomes again
Spindle apparatus breaks down and nuclear membranes reform.

Question 7

Cytokinesis.

Answer 7

The central membrane is pulled inwards by the cytoskeleton.
This creates a groove which gradually deepens.
Eventually membranes fuse to form 2 independent cells.

Question 8

Differences in plant cell mitosis.

Answer 8

Centrioles don’t play a role forming spindle apparatus as plant cells don’t have them.
During cytokinesis, plant cell membrane can’t form form a furrow as in animal cells.
Instead vesciles from the golgi apparatus form membrane structures.