mitosis and the cell cycle

what is mitosis

Mitosis is the part of the cell cycle in which a eukaryotic cell divides to produce two daughter cells, each with the identical copies of DNA produced by the parent cell during DNA replication.

what are the 6 stages of the cell cycle

interphase

prophase

metaphase

anaphase

Telophase

Cytokinesis

what happens during interphase

DNA Replication

what happens during prophase

chromosomes condense and become visible (appear as chromatids joined at the centromere)

centrioles move to poles of the cell

spindle fibres develop

nuclear envelope breaks down

what happens during metaphase

chromosomes line up at equator of cell

centromeres attach to spindle fibres at the centromeres

what happens during anaphase

spindle fibres contract (shorten) and centromere divides and 1 chromatid from each pair is pulled to opposite poles (energy provided by mitochondria)

what happens during telophase

chromosomes become longer and thinner (uncoil)

nuclear envelope reforms

what happens during cytokinesis

cytoplasm divides and 2 identical cells are created

process of binary fission

circular DNA replicates

plasmids replicate

division of the cytoplasm to produce two daughter cells, each with a single copy of the circular DNA and a variable number of copies of plasmids.

new cell wall forms

as viruses are non living 9viruses cell replication)

viruses do not undergo cell division. Following injection of their nucleic acid, the infected host cell replicates the virus particles.

what is cancer caused by

uncontrolled cell division leads to the fomrations of tumours and cancers, often caused by mutation in gene during mitosis

malignant tumours

grow rapidly, spread and are more likely to be life threatening

bening tumours

grow slower and are more compact therefore less likely to be deadly

treatment of cancers often involves

directed at controlling the rate of cell division.

how do cancer drugs interfere with the cell cycle

prevent DNA from replicating

inhibit the metaphase of cell cycle by interfering with spindle fibre formation