Uncontrolled Cell Division & Cancer Flashcards
Cancerous cells divide repeatedly and uncontrollably, forming a
tumour (an irregular mass of cells)
Cancers demonstrate how important it is that cell division is precisely controlled, as cancers arise due to
uncontrolled cell division
Cancers start when changes occur in the
genes that control cell division
A random change in any gene is known as a
mutation
If the mutated gene is one that causes cancer it is referred to as an
oncogene
Mutations are common events and don’t lead to cancer most of the time
Most mutations either result in
early cell death or result in the cell being destroyed by the body’s immune system
As most cells can be easily replaced, these events usually have no harmful effect on the body
The mutations that result in the generation of cancerous cells do not result in ………………..
This means that the harmful mutation occurring in the original cell can be passed on to all that cell’s descendants
A typical tumour contains around a thousand million cancerous cells by the time it is detected
early cell death or in the cell being destroyed by the body’s immune system
Carcinogens are
and examples
Carcinogens are any agents that may cause cancer (eg. UV light, tar in tobacco smoke and X-rays). If the agent causes cancer it is described as carcinogenic
Some tumours (such as warts) do not spread from their original site – these are known as
benign tumours and do not cause cancer
Some tumours spread through the body, invading and destroying other tissues – these are known as……………. and …………… cancer
malignant tumours
Malignant tumours interfere with the normal functioning of the organ / tissue in which they have started to grow (eg. they may block the
intestines, lungs or blood vessels
Malignant tumour cells can break off the tumour and travel through the
blood and / or lymphatic system to form secondary growths in other parts of the body
malignant tumour cells can break off the tumour and travel through the blood and / or lymphatic system to form secondary growths in other parts of the body
The spreading of cancers in this way is known as
Metastasis is very dangerous as it can be very difficult to detect, locate and remove secondary cancers
Viruses like what can cause cancer
HPV cervical
