AS AQA Biology - Disease

Pathogens cause disease.

Types of pathogens include bacteria, fungi, and viruses. 

Pathogens can enter an organism in 3 ways:

• Gas exchange system - breathing in the pathogens
• Skin - damaged skin lets pathogens enter
• Digestive system - eating/drinking substances containing pathogens

Pathogens can cause disease in 2 ways:

• Releasing toxins - these can block the function of nerve cells
• Damaging cells - by either rupturing them to release their nutrients, using their nutrients until they starve, or replicating inside them and causing them to burst. 

Lifestyle can increase the risk of developing disease...

The risk of coronary heart disease can be increased by:

• Having a poor diet - high in fats/salts
• Smoking
• Lack of exercise
• Excessive alcohol intake

The risk of cancer can be increased by:

• Excessive exposure to sunlight
• Excessive alcohol intake - especially liver cancer
• Smoking - especially lung/mouth cancer

Changing your lifestyle decreases the risk of disease.