Cell Cycle (4.2) Flashcards
1
Q
What is cell division important for?
A
- embryo development
- growth
- homeostasis (replacing old /dead cells)
- cancer
2
Q
What does most cell division result in?
A
- daughter cells with identical genetic infromation, DNA - mitosis
- cell division linked to reproduction - meiosis
- highly organised process
3
Q
What are the steps in the cell cycle?
A
- cell growth + chromosome replication
- chromosome segregation
- cell division
4
Q
Where does most cell division take place?
A
The bone marrow
5
Q
What are cells that never divide called?
A
Post-Mitotic Cells
6
Q
What are cells that lose the ability to divide during ageing called?
A
Senescent Cells
7
Q
What happens in the G1 phase?
A
- cell undergoes protein synthesis
- lots of gene transcription + RNA synthesis occurring
- cells duplicate their organelles e.g. ER, mitochondria
- so that the needs of the daughter cells can be satisfied.
- cells = highly metabolically active, therefore require lots of energy
8
Q
What happens in the S phase?
A
- cell has grown big enough, begins to duplicate its DNA
- extra copy of each chromosome = made, and joined at the centromere
9
Q
What happens in the G2 phase?
A
- period of rapid growth, as cell readies itself for mitosis
- cell checks its DNA to make sure it has been copied correctly
10
Q
What happens in the M phase?
A
- fastest stage
- nuclear envelope breaks downs
- mitotic spindle forms + chromosomes are separated
- Cell splits into two (cytokinesis)
11
Q
What stages are involved in the M phase?
A
- Prophase
- Pro-metaphase
- Metaphase
- Anaphase
- Telophase
12
Q
What happens during prophase?
A
- chromatin in the nucleus condenses into chromosomes - becomes visible
- nucleolus in the nucleus disappears
- nuclear envelope breaks down
- microtubule activity increases at the centrosomes
13
Q
What happens in prometaphase?
A
- as nuclear envelope breaks down
- microtubules emerge from the spindle poles + start searching for a chromosome to capture
- 1 microtubule from the spindle attaches to the kinetochore in the chromosome’s centromere
- once another microtubule from the other spindle pole attaches to the centromere, forces exerted by protein motors move the chromosomes toward the centre of the cell
14
Q
What happens in Metaphase?
A
- the chromosomes align at the centre of the cell, along the metaphase plate
15
Q
What is the kinetochore?
A
- a structure that attaches chromosomes to the microtubule, leading to the segregation of the chromosomes
