Cells 1.6 Cell division

Question 1

Why do eukaryotes need to do mitosis?

Answer 1

1. embryonic development
2. repair
3. growth
4. asexual reproduction

Question 2

Draw and explain the process for mitosis.

Answer 2

Mitosis

Prophase The nuclear is broken down. The DNA condenses to be visible chromosomes through supercoiling. Spindle fibers grow from each of centrioles

Metaphase

The chromosomes line up at the equator. The spindle fibers attach themselves to each chromatid.

Anaphase

The spindle fibers shorten as the chromatids are now pulled apart into sister chromatids.

Telophase

Chromosomes uncoil. The 2 nuclear membranes form around each pole. Spindle fibers break down.

Interface

Question 3

What happens in the interface?

Answer 3

Interphase is a very active part of the cell cycle. In this part, many processes occur in the nuclear and cytoplasm.

Question 4

In what phase of the cell cycle is this cell in?

Answer 4

Interphase

Question 5

In what phase of the cell cycle is this cell in?

Answer 5

Prophase

Question 6

In what phase of the cell cycle is this cell in?

Answer 6

Metaphase

Question 7

In what phase of the cell cycle is this cell in?

Answer 7

Anaphase

Question 8

In what phase of the cell cycle is this cell in?

Answer 8

Telophase

Question 9

In what phase of the cell cycle is this cell in?

Answer 9

Cytokinesis

Question 10

How do you calculate a mitotic index?

Answer 10

Mitotic index = (total number of cells doing mitosis)/(total number of cells)

Question 11

What is the mitotic index used for?

Answer 11

Mitotic index is often used for doctors to determine whether the patient has cancer, as well as the chance of the patient’s survival, and whether or not the patient will respond positively or negatively to chemotherapy.

Question 12

Compare cytokinesis between animal and plant cell.

Answer 12

Animal cells do not have cell walls. Plant cells have cell walls that is created through a cell plate. Vesicles do not line up in an Animal Cell.Vesicles line up along the equator in Plant cells. Animal cells are separated by cleavage furrow. Plant cells are not separated by cleavage furrow. List similarities eg. Both plant and animal cells’ cytoplasm is separated. Both plant and animal cells form 2 genetically identical daughter nuclei.

Question 13

What are cyclins?

Answer 13

Cyclins are proteins that control the progression of cells through the cell cycle by activating enzymes.

Question 14

What causes cancer?

Answer 14

**Mutagens: **physical or chemical factor that causes DNA mutations

• physical (UV, Xray, gamma radiation)
• Chemical (polonium, carbon monoxide, radium)

**Oncogenes: **genes that have the potential to cause cancer. Usually have rapid growth

**Metastasis: **when cancerous cells break off from a tumour, they travel in the body stream, and cause new tumours elsewhere.

Question 15

What kind of cell division does tumour present?

Answer 15

Tumour presents an example of an uncontrolled cell division.