Mitosis

Question 1

What are the two types of cell division

Answer 1

Mitosis and Meiosis

Question 2

What is mitosis needed for

Answer 2

Growth of multicellular organisms and repairing damaged tissues

Question 3

Do all cells regain the ability to divide?

Answer 3

No

Question 4

What occurs in the cell cycle

Answer 4

Synthesis - Gap phase - Mitosis - Gap phase 2 -

Question 5

How many stages does Mitosis have

Answer 5

4

Question 6

What happens in Interphase

Answer 6

The cell carries out normal functions, but also prepares to divide:

• Cells DNA unravelled + replicated (double genetic content)
• Organelles are also replicated
• ATP content increased (energy needed for cell division)

Question 7

What are the stages of Mitosis

Answer 7

1: Prophase
2: Metaphase
3: Anaphase
4: Telophase

Question 8

What happens in Prophase

Answer 8

• Chromosomes condense (shorter and fatter)
• Centrioles start moving to opposite ends of the cell
• Centrioles form spindle fibres
• Nuclear envelope breaks down and chromosomes lie free in the cytoplasm.

Question 9

What is a centriole

Answer 9

Tiny bundles of protein

Question 10

What is a nuclear envelope

Answer 10

The membrane around the nucleus

Question 11

What happens in Metaphase

Answer 11

• The chromosomes (each with two chromatids) line up along the middle of the cell and become attached to the spindle by their centromere

Question 12

What happens in Anaphase

Answer 12

• The centromeres divide, separating each pair of sister chromatids
• the spindles contract, pulling chromatids to opposite ends of the spindle, centromere first
• Makes the chromatids appear v-shaped

Question 13

What happens in Telophase

Answer 13

• Chromatids reach the opposite poles on the spindle
• They uncoil and become long and Thin
• They’re called chromosomes again
• A nuclear envelope forms around each group of chromosomes, now there are 2 nuclei
• The cytoplasm divides (cytokinesis) and there are now two daughter cells
• Daughter cells start interphase ready for start of mitosis

Question 14

How to calculate the length of mitosis

Answer 14

Example:
100 cells undergoing mitosis. 10 of which are in metaphase. This suggests that the proportion of cells in metaphase must be 10/100th of the cell cycle. You’re told the cell cycle lasts 15 hours. (15*60) = 900 mins. 10/100 * 900 is 90 mins in metaphase.

Question 15

How does cancer form

Answer 15

Uncontrolled cell division.

Question 16

What are mitosis and the cell cycle controlled by

Answer 16

genes