5a + 5b: The Cell Cycle Flashcards
What does the cytoskeleton do
Gives mechanical support and shape to cells
What are microtubules
Hollow cylinders composed of the protein Tubulin. They radiate the microtubule organising centre (MTOC) or centrosome.
The formation and breakdown of microtubules involve….
The polymerisation and depolymerisation of Tubulin
functions of the microtubules
- mechanical support for shape
- remodelling the cytoskeleton for cytokinesis
- controlling movement of the membrane- bound organelles and chromosomes.
The cell cycle consists of…
Interphase and the mitotic phase
What does interphase involve
Growth and DNA synthesis
Stages of interphase
G1 - growth phase
S - DNA is replicated
G2 - a further growth phase
What does the mitotic phase involve
Mitosis and cytokinesis
In mitosis, what is the chromosomal material separated by
The spindle microtubule
What is cytokinesis
The cytoplasm is separated in 2 daughter cells
What is mitosis
The process of nuclear division that occurs before a cell divides by two
Stages of mitosis
PMAT
Prophase
Metaphase
Anaphase
Telophase
what is prophase
- The DNA condenses into discrete chromosomes (each chromosome=2 identical sister chromatids) joined at the centromere
- the nuclear membrane breaks down
- spindle fibres extend from the MTOC by polymerisation and attach to chromosomes via their kinechores in the centromere region
What is metaphase
the chromosomes line up at the metaphase plate (equator of the spindle)
What is anaphase
- As spindle microtubules shorten by depolymerisation, sister chromatids are separated (once part the chromatids can now be called chromosomes)
- The chromosomes are pulled to the opposite end of the cell.
