Mitosis 2A Flashcards
What is mitosis
A type of cell division where a parent cell divides to form two genetically identical daughter cells. Mitosis is needed for growth, repair and replacing cell number
Cell cycle stages
interphase, G1, S, G2
What happens during interphase
Cell carries out normal functions but also prepares to divide. Cells DNA is unravelled and replicated. Organelles are also replicated and its ATP content is increased
What happens during prophase
Chromosomes condense
Centrioles start moving to opposite ends of the cell forming the spindle
Nuclear envelope breaks down
What happens during metaphase
The chromosomes line up along the middle of the cell and become attached to the spindle by their centromere
What happens during anaphase
Centromeres divide, separating each pair of sister chromatids, spindles contract pulling chromatids to opposite poles of the spindle
What happens during telophase
Chromatids reach opposite poles on the spindle, they uncoil and become long and thin. A nuclear envelope forms around each group of chromosomes. Cytoplasm divides (cytokinesis) there are now two genetically identical daughter cells and the cycle stats again
What is a tumour
A mass of cells as a result if uncontrolled cell division can be begin or malignant and are usually caused by a mutation in the gene controlling division
How do cancer treatments work
Some target the cell cycle by disrupting it which kills the tumour cells but these treatments do not distinguish between cancerous cells and normal cells. However tumour cells divide more frequently than normal cells so are more likely to be destroyed by the cancer treatments
Chemotherapy - Prevents synthesis of enzymes needed for DNA replication so cell cannot enter S phase forcing it to kill itself
Radiation - Damage DNA so cells cannot pass checkpoints so will be forced to kill itself
