1.5: Protein control of cell division Flashcards
One type of cytoskeleton protein fibre. Hollow cylinders made of the protein tubulin subunits.
Microtubules.
Functions of the cytoskeleton.
Cell shape OR Mechanical support OR Organelle attachment OR Movement of vesicles OR Remodelled to form spindle fibre.
Polymerisation (lengthens) and depolymerisation (shortens) of microtubules to give the cytoskeleton its dynamic propeties. Also builds the spidnle from tubulin subunits.
Microtubule organising centre (MTOC) OR Centrosome.
Results from an uncontrolled reduction in the rate of cell cycle.
Degenerative disease.
Abnormal mass of cells produced by an uncontrolled increase in the rate fo the cell cycle.
Tumor
A normal gene involved in the control of cell growth which can mutate to form a tumor-promoting oncogene.
Proto-oncogene.
Sequence of the cell cycle.
G1, S, G2, M then Cytokinesis.
Overall name for the stages of the cell cycle that prepare the cell for mitosis.
Interphase.
Occurs during the G1 and G2 stages of interphase.
Cell growth.
Occurs during the S phase of interphase.
DNA Replication
Sequences of the mitosis stages.
Prophase, metaphase, anaphase then telophase.
Stage of mitosis when the DNA condenses into chromosomes each consisting of two sister chromatids.
Prophase.
Stage of mitosis when the chromosomes attach to the spindle at cell equator (metaphase place).
Metaphase.
Stage of mitosis where as spindle microtubules shorten by depolymerisation, sister chromatids are
separated, and the chromosomes are pulled to opposite poles.
Anaphase.
Stage of mitosis when chromosones decondense and two nuclei form.
Telophase.
Cell cycle stage where the seperation of the two nuclei and cell contents into two daughter cells occurs.
Cytokinesis.
Microtubule structure involved in the arrangement of chromosones on the metaphase plate and seperation of sister chromatids.
Spindle
Critical points in cell division where “stop” and “go ahead” signals regulate the cycle. They occur in the g1, g2 and M phases of the cell cycle.
Checkpoints.
Critical “go ahead”signals required to pass the G1 checkpoint.
Big enough OR No DNA damage OR growth factor arrived.
Critical “go ahead” signal required to pass the M checkpoint.
All chromosomes attached to the spindle.
Non-dividing state that a cell enters if it does not recieve the “go ahead” signal at the G1 checkpoint.
G0
Proteins that acumulate at each stage of the cell cylce and activate cyclin-dependent kinases (CDK) enzymes.
Cyclins
Enzymes activated by cyclin proteins. They phosphorylate proteins involved in progressing the cell cycle.
Cyclin-dependant kinases OR Cdks.
When sufficient proteins have been phosphorylated the cell moveson to the next stage of the cell cycle. Held at a checkpoint if insufficient.
Threshold of phosphorylation.
Tumor suppressor inhibitor of transcription which is phosphorylated by G1 Cdks to allow the synthesis of various proteins required for DNA replication in the S stage.
Retinoblastoma OR Rb
Protein activated by DNA damage.
p53
Cell processes stimulated by p53 tumor-suppressor protein activation.
DNA repair OR Cell cycle arrest OR Cell death/ Apoptosis.
Programmed cell death triggered by signals that may originate within or outith the cell.
Apoptosis
Family of protease enzymes that play an essential role in apoptosis by causing cell destruction.
Caspases
External death signal that triggers apoptosis.
Death signal from lymphocyte OR Growth factor absence
Internal death signal that trigers apoptosis.
Irreperrable DNA damage OR Activation of p53.
Removes cells no longer required duing te development of an organism o during metamorphosis.
Apoptosis.
