Topic 2: Cells and Control

Question 1

What are the stages of the Cell Cycle?

Answer 1

• Interphase
• Cell division:
- Mitosis
- Cytokinesis

Question 2

What occurs during Interphase?

Answer 2

• Replication of organelles (eg. Mitochondria)
• Replication of DNA (doubling chromosomes)

Question 3

What are the 4 Stages of Mitosis?

Answer 3

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

Question 4

What occurs doing Prophase?

Answer 4

• Chromosomes condense (shorter + fatter)
• Nuclear membrane breaks down
• Spindle fibres begin to appear

Question 5

What occurs doing Metaphase?

Answer 5

• The chromosomes line up along the centre of the cell (the equator)
• Spindle fibres attach to chromosomes

Question 6

What occurs doing Anaphase?

Answer 6

• Spindle fibres contract + pull chromosomes apart
• Chromatids are pulled to opposite ends of the cell

Question 7

What occurs doing Telophase?

Answer 7

• New nuclear membranes form around the chromosomes
• These become the nuclei of the two new cells

Question 8

What is Cytokinesis?

Answer 8

Where the cytoplasm and cell membrane divide to form two separate ‘daughter’ cells.

Question 9

What are the uses of Mitosis?

Answer 9

• Repair/Replacement of damaged cells
• Growth
• Asexual Reproduction

Question 10

Define Growth

Answer 10

A permanent increase in size as a result of an increase in the number or size of cells.

Question 11

What is Isometric growth?

Answer 11

Where body proportions stay the same (eg. Salamanders)

Question 12

What is Allometric growth?

Answer 12

Where different parts of the body grow at different rates (eg. Humans).

Question 13

What is Cell Differentiation?

Answer 13

The process by which a cell changes to become specialised for its job.

Question 14

Animal Growth

Answer 14

• Through cell division
• Occurs when they’re young, reach maturity + stop
• Embryonic stem cells are undifferentiated, adult cells specialise

Question 15

Plant Growth

Answer 15

• Continuous growth
• Cell division occurs at shoots, roots and tips (meristems)
• Growth in height due to cell elongation

Question 16

What are Stem cells?

Answer 16

Undifferentiated cells that can rapidly divide and develop into specialised cells.

Question 17

Where are stem cells first found in humans?

Answer 17

Embryonic Stem Cells, can produce any kind of cell

Question 18

Where are Adult stem cells found?

Answer 18

• In the bone marrow
• Can only produce certain types of cell (eg. Red Blood Cells)

Question 19

What are the issues associated with using Stem cells in medical treatments?

Answer 19

• Tumour development (unchecked growth)
• Disease transmission (particularly viruses)
• Risk of Rejection (triggers immune response)