1.5 Protein Control of Cell Division Flashcards
What does the cell cycle consist of?
Interphase and Mitotic Phase
What does the mitotic phase consist of?
Mitosis and Cytokinesis
What does mitosis consist of?
Prophase, Metaphase, Anaphase and Telophase
Cytoskeleton
Gives mechanical support and shape to cells
Microtubules
Control the movement of membrane-bound organelles and chromosomes
Microtubule Formation
Polymerisation of Tubulin
Microtubule Breakdown
Depolymerisation of Tubulin
Stages of Interphase
G1, a growth phase; S phase, during which the DNA replicates; and G2, a further growth phase in preparation for mitosis.
G1 Checkpoint
Retinoblastoma protein (Rb) acts as a tumour suppressor by inhibiting the transcription of genes that code for proteins needed for DNA replication. Phosphorylation by G1 cyclin-CDK inhibits the Rb
G2 Checkpoint
Success of DNA replication and any damage to DNA is assessed
DNA Damage Process
DNA damage triggers activation of p53 that can stimulate DNA repair, arrest the cell cycle or cause cell death
Metaphase Checkpoint
Controls progression from metaphase to anaphase
Degenerative Disease
Uncontrolled reduction in rate of cell cycle
Tumour Formation
Uncontrolled increase in rate of cell cycle
Proto-Oncogene
Normal gene, usually involved in the control of cell growth or division, which can mutate to form a tumour-promoting oncogene
How is apoptosis triggered?
Internal or External Death Signals
External Death Signalling
Signal molecules bind to a surface receptor protein and trigger a protein cascade within the cytoplasm
Internal Death Signalling
Results from DNA damage causing activation of p53 tumour-suppressor protein
What do both types of death signals activate?
Caspases (types of protease enzyme) which break down proteins
Apoptosis
Programmed cell death, which can occur during normal growth and development, resulting in the removal of old or damaged cells or during metamorphosis in certain species.
