1
Q
what does mitosis produce?
A
- it produces 2 genetically identical daughter cells
2
Q
what is mitosis needed?
A
- for the growth of multicellular organisms
- to repair damaged cells
3
Q
cells follow a —- —— for mitosis to occur
A
cell cycle
4
Q
define a cell cycle
A
a period of cell growth and DNA replication, called interphase, which prepares the cell for mitosis.
5
Q
name and define the phases in interphase
A
- Mitosis: the cycle starts and ends here
- Gap Phase One: cell grows and new organelles and proteins are made
- Synthesis: cell replicates its DNA, ready to divide by mitosis
- Gap Phase 2: cell keeps growing and proteins needed for cell division are made
6
Q
name the four stages of mitosis in order
A
1- Prophase
2- Metaphase
3- Anaphase
4- Telophase
7
Q
outline what happens in Prophase
A
- chromosomes condense getting shorter and fatter
- centrioles move to opposite poles of the cell
- nuclear envelope breaks down, and chromosomes lie free in the cytoplasm
8
Q
outline what happens in Metaphase
A
- chromosomes line up along the middle of the cell
- chromosomes attach to the spindle fibres at the centromere
9
Q
outline what happens in Anaphase
A
- centromeres divide, separating the sister chromatids
- spindle fibres contract, pulling the chromatids to opposite poles of the cell
- this makes the chromatids appear V-shaped
10
Q
outline the process of telophase
A
- chromatids uncoil, becoming long and thin again, they are now called chromosomes again
- a nuclear envelope forms around each group of chromosomes, forming two nuclei
- cytokinesis occurs, dividing the cytoplasm
- two genetically identical daughter cells are produces
- interphase begins again for the next cycle.
11
Q
what are mitosis and the cell cycle controlled by?
A
Genes
12
Q
describe how tumours are formed
A
- a mutation in the gene causes cells to grow out of control, meaning they keep dividing to develop a tumour
13
Q
define cancer
A
cancer is a tumour which invades surrounding tissues, forming secondary tumours.
14
Q
some cancer treatments target the —– ——-
A
cell cycle
15
Q
A
