Cell Division

Question 1

What happens in Stage 1 of mitosis?

Answer 1

Replicate DNA
2 copies of each chromosome form
increase in sub cellular structures
increased mass

Question 2

What happens in Stage 2 of mitosis?

Answer 2

Chromosomes pulled to each end of cell

Nucleus divides

Question 3

What happens in Stage 3 of mitosis?

Answer 3

Cytoplasm and cell membrane divide

Forming 2 identical daughter cells

Question 4

Describe the whole mitosis process

Answer 4

1) Cell begins to divide
2) DNA replicates to form 2 copies of each chromosome
3) The nuclear membrane breaks down. The chromosomes line up across the centre of the cell
4) Increasing the number of sub-cellular structures
4) One set of chromosomes is pulled to each end of the cell and the nucleus divides
5) The cytoplasm and cell membranes divide to form to identical daughter cells

Question 5

What is meant by the term Differentiation?

Answer 5

The process by which cells, tissue, and organs acquire specialized features

Question 6

Where are undifferentiated cells formed in plants?

Answer 6

meristems

Question 7

How do you produce an identical offspring plants?

Answer 7

Known as cloning

1) Take explants from the parent plant
2) Transfer to plates containing sterile agar jelly
3) Add plant hormones to stimulate the plant cells to divide
4) Cells grow rapidly into small masses of plant tissue
5) Add more plant hormones to stimulate the growth of roots and stems
6) Transfer the plantlets into potting trays, where they develop into plants

Question 8

Where can stem cells be obtained?

Answer 8

Adult stem cells = bone marrow and tubes liver & tubes from pancreas -> small intestine
Embryonic stem cells = umbilical cord and amniotic fluid

Question 9

How can stem cells in plants be used?

Answer 9

Producing large numbers of rare plants 
Disease resistant plants
Horticulture 
Stop extinction
Medicine

Question 10

Problems with embryonic stem cells

Answer 10

Very limited = donated
Violation of human rights = can’t give consent
Religious beliefs = interfering with human reproduction
Developing therapies is slow, difficult, expensive and hard to control
Can cause cancer
Difficult to persuade embryonic stem cells into different types of cells needed
Chance of rejection
Need to take drugs to stop body rejecting them
Money and time being wasted
Risk of infection

Question 11

Therapeutic Cloning

Answer 11

Provides perfectly matched stem cells
Not rejected by body
Same genes