B2 Cell Division

Question 1

Describe the cell cycle

Answer 1

Stage 1 Interphase:
Cells increase and DNA replicates, with mitochondria and ribosomes also replicating
Stage 2 Mitosis:
Chromosomes line up at the centre of the cell
Spindle contracts
The replicated chromosomes are pulled to either ends of the cell
The nucleus divides into two
Stage 3 Cytokinesis:
Cytoplasm and cell membrane divide and 2 new identical cells are formed

Question 2

What are stem cells?

Answer 2

Cells that can differentiate into specialised cells and able to divide by mitosis

Question 3

What are embryonic stem cells?

Answer 3

Stem cells found within an embryo that can differentiate into any type of cell. A disadvantage is that they are unethical

Question 4

What are adult stem cells?

Answer 4

Stem cells found in adults that can be painfully extracted and divide by mitosis but can only differentiate into blood cells