Chapter 2 - Cell Division

Question 1

How many chromosomes and pairs are found in a nucleus?

Answer 1

• 46 chromosomes (23 pairs)

Question 2

What is the cell cycle?

Answer 2

• When body cells divide to form 2 identical daughter cells.

Question 3

Define mitosis.

Answer 3

• When genetic material divide into 2 identical nuclei.

Question 4

Describe the 3 stages of the cell cycle.

Answer 4

Stage 1 - Cells grow bigger/increased mass. Replication of DNA for cell division. Increase in number of sub-cellular structures (ribosomes, mitochondria).

Stage 2 - (Mitosis) One set of chromosomes is pulled to each end of dividing cell. Nucleus divides.

Stage 3 - Cytoplasm + Cell membrane divide to form 2 identical daughter cells.

Question 5

Define gene.

Answer 5

• Packet of info that controls a characteristic.

Question 6

Define chromosome. [1]

Answer 6

• A large group of genes. [1]

Question 7

What is a stem cell and where is it produced? [2]

Answer 7

• An unspecialised cell that can differentiate into any type of cell [1]
• Produced from human embryos. [1]

Question 8

Define differentiation.

Answer 8

• When a less specialised cell develops into a more specialised cell type.

Question 9

What are adult stem cells and where are they produced?

Answer 9

• A specialised cell which can only repair specific cells.

- Produced in bone marrow.

Question 10

Where does mitosis take place in plant cells?

Answer 10

• Takes place in the meristem found in the shoot + root tips.

Question 11

Explain how treatment with stem cells can be effective. [2]

Answer 11

• Stem cells can be used to cure conditions [1] such as paralysis and diabetes, usually incurable. [1]

Question 12

Give 3 uses for stem cells in plants. [3]

Answer 12

• Produces new plants clones. [1]
• Research purposes. [1]
• For agriculture. [1]

Question 13

Give 3 diseases that are being researched to try and treat them. [3]

Answer 13

• Diabetes [1]
• Blindness [1]
• Damaged bone/cartilage [1]

Question 14

Give 3 reasons why people might object against the use of stem cells. [3]

Answer 14

• Stem cells can be born into potential fetuses. [1]
• Waste of time and money for research and use. [1]
• The stem cell can pick up and spread a virus into the patient. [1]