Biology- Lifestyle health and risk

Unit 1 topic 1

What is the definition of health?

Health is the state of complete physical, mental and social wellbeing and not merely the absence of disease. Poor health can be due to controllable factors such as lifestyle choices as well as uncontrollable factors such as inherited diseases

Why are circulatory systems important?

We need mass transport systems to overcome limitations of diffusion to meet the requirements of the organisms

Why do larger organisms require specialised mass transport systems?

larger transport distances

Surface area : volume ratio

Increasing levels of activity

This is because they have more cells that need to be provided with nutrients and glucose as well as being more complex, therefore needing more energy.

How do unicellular organisms obtain nutrients and excrete waste?

Unicellular organisms such as bacteria use diffusion