Human Biology Notes- the cell cycle and cancer

This is the stage of the cycle the cell spends most of its time in.

Mitosis

Cytokinesis

This is when the spindle fibres, after Mitosis, form a draw string at the centre of the cell, just inside the plasma membrane, and this pinches inwards and fuses. The cytoplasm is split equally, along with the cell organelles.

Apoptosis

This is programmed cell suicide. This is important for cells that are infected with a virus and may be a threat to other cells, or cells with damaged DNA, that may become cancerous. It is also in normal development, such as the shedding of the lining of the uterus during menstruation, and the formation of synapses between neurones in the brain.

Cancer

Tumours are masses of abnormal cells that have grown when there is no need for growth or repair. Benign tumours are tumours that grow in one place, and do not spread. Malignant tumours are those that can spread to neighbouring tissues by the blood or lymph systems. This is called metastasis, in which they can start secondary tumours, or metastases.

Causes of Cancer

Detecting Cancer

Breast Cancer