6.1 Cell Cycle Flashcards
What are the 2 main phases of the cell cycle?
- INTERPHASE
- MITOSIS
What is interphase?
Growth period of cell cycle
between mitotic phases
What processes occur during interphase?
- DNA replicated + checked for errors
- Protein synthesis in cytoplasm
- Chloroplasts/Mitochondria grow & divide
- Normal metabolic processes carry on occurring
What are the 3 phases of interphase?
- G1
- S
- G2
What occurs during G1 of interphase?
- protein synthesis
- organelles replicate using proteins from synthesis
- cell increases in size
What occurs during S phase of interphase?
- DNA replicates in nucleus
What occurs during G2 of interphase?
- Cell continues to increase in size
- Energy stores increased
- Replicated DNA checked for errors
What is the mitotic phase of the cell cycle?
Period of cell division
What are the 2 main stages of mitosis?
- MITOSIS - division of nucleus
- CYTOKINESIS - division of cytoplasm to form 2 cells
What is G0?
Phase during which cell leaves cell cycle
either temporarily or permanently
For what reasons may a cell enter G0?
- DIFFERENTIATION
- differentiated cells no longer divide
- DAMAGED DNA
- Cells which are damaged due to damaged DNA do not divide, in order to not create more damaged cells
- SENESCENCE
- senescence = process by which cell “ages”.
- cells can only divide limited number of times before becoming senescent.
What is the purpose of checkpoints within the cell cycle?
- monitor & verify whether each stage has been completed correctly
- before the cell is allowed to progress to the next phase.
What is the purpose of the G1 checkpoint?
To check the following criteria:
- cell size
- nutrients
- growth factors
- DNA damage
What is the purpose of the G2 checkpoint?
To check the following criteria:
- cell size
- DNA replication
- DNA damage
What is the purpose of the spindle assembly checkpoint/metaphase checkpoint?
To check the following criteria:
- chromosome attachment to spindle
