B2 - Cell Division

Question 1

What is the first stage of the cell cycle?

Answer 1

• The cell grows bigger and increases the number of organelles
• Its DNA is then replicated to make 2 copies of each chromosome
• The cell is then ready for Stage 2 Mitosis

Question 2

What happens during stage 2 of the cell cycle?

Answer 2

• Stage 2 is where Mitosis happens
• The membrane around the nucleus disappears and the chromosomes line up in the middle of the cell
• The copies of the chromosomes are then pulled apart to each end of the cell, dividing the nucleus

Question 3

What happens during Stage 3 of the Cell Cycle?

Answer 3

• In Stage 3 a nucleus membrane forms around each group of chromosomes and the cytoplasm divides to make 2 identical daughter cells from 1 parent cell.
• This is called cytokinesis

Question 4

What is mitosis?

Answer 4

It is the stage of the cell cycle when the cell divides

Question 5

What is growth?

Answer 5

Growth is the process of cell division followed by the cells becoming specialised

Question 6

What is differentiation?

Answer 6

Differentiation is the process of undifferentiated stem cells becoming specialised
E.g. muscle cells, nerve cells, brain cells, sperm cells

Question 7

What cells cannot divide?

Answer 7

Any specialised cell cannot divide for e.g. Red blood cells so in that case adult stem cells have to replace the dead or damaged red blood cells

Question 8

What cant nerve cells do?

Answer 8

They cannot divide

Question 9

What part of the plant contains undifferentiated stem cells?

Answer 9

The meristems

Question 10

How do you clone a plant?

Answer 10

The simplest way to clone a plant involves taking a cutting. A branch from the parent plant is cut off, its lower leaves are removed, and the stem is planted in damp compost. Plant hormones are often used to encourage new roots to develop. The cutting is usually covered in a clear plastic bag to keep it moist and warm.

Question 11

What is a stem cell?

Answer 11

A stem cell is a cell that has not yet become a specialised cell

Question 12

Where are embryonic stem cells found and what can they do?

Answer 12

Embryonic stem cells are found in early human embryos and they have the potential to differentiate into any cell. Usually discarded after IVF

Question 13

Where are adult stem cells found and what do they do?

Answer 13

Adult stem cells are found in bone marrow and unlike embryonic stem cells they cant turn in to any cell type but they can only turn in to certain ones such as blood cells

Question 14

How do you do therapeutic cloning?

Answer 14

• First you get a human egg from a donor and remove the nucleus
• Then you get the cell from the patient and transfer the cells nucleus into the human egg
• The cell is then stimulated to divide
• The cell then develops into a embryo
• After 4-5 days stem cells are removed

Question 15

Stem cells can be used to cure what type of diseases?

Answer 15

Things like - diabetes, paralysed by spinal injuries

Question 16

Why are some people against stem cell research?

Answer 16

• Some people are against stem cell research because they believe that human embryos shouldn’t be used for experiments since each one is a potential human life.
• Other people think that curing existing patients who are suffering is more important than the rights of embryos