Chapter 6 - Cell division Flashcards
What is a cell cycle ?
Highly ordered sequence of events leading to division of the cell into identical daughter cells
What are the two phases of the cell cycle ?
1) Interphase
2) Mitotic phase
What is the interphase ?
Phase of periods of growth, where cells are not actively dividing
What occurs at interphase ?
- DNA is replicated and checked for errors
- Protein synthesis occurs
- Mitochondria grow and divide in plant and algal cytoplasms
What are the stages interphase is split into ?
G1 stage
S stage
G2 stage
What occurs at each stage of interphase ?
G1 - First growth phase
Proteins are synthesised
Cells increase in size
S - DNA is replicated within nucleus
G2 - Cells continously increase in size
Energy source is increased and duplicated
DNA is checked for errors
What are the different checkpoints at interphase ?
Where are they located ?
G1 checkpoint - After G1 phase
G2 checkpoint - After G2 phase
Metaphase checkpoint - During metaphase
What does the G1 checkpoint check ?
- Cell size
- Nutrients
- Growth factors
- DNA damage
What does the G2 checkpoint check ?
- DNA replication has any errors
- Cell size
- DNA damage
What does the metaphase checkpoint check ?
- Chromosomes are attached to spindle fibres
- Mitosis can continue to occur without this checkpoint
What is the mitotic phase ?
- Period of cell division
- Mitosis and cytokenisis occur
What is the mitotic phase needed for ?
- Asexual reproduction
- Growth
- Repair
- Replacement of tissue
What must occur before the Mitotic phase ?
Replication of DNA i.e. Interphase
What are the four stages of mitosis ?
(I) - [Interphase]
Party - Prophase
More - Metaphase
At - Anaphase
The - Telophase
Club - Cytokenisis
What occurs at the prophase ?
- Chromatin fibres coil and condense to form chromosomes
- Nucleur membrane begins to break down
- Microtubules form spindle fibres linking poles
- Spindle fibres move chromatic
- Centrioles migrate to either ends of the cell
- Nucleur envelope disintegrates