Term 1 Lesson 1: Diffusion

Question 1

What is diffusion?

Answer 1

When particles move from a HIGH concentration to a LOW concentration.

It is PASSIVE. It will happen on it’s own.

Question 2

What do we mean by concentration?

Answer 2

How much stuff there is in an area. A high
concentration of particles means there are lots of them.

Question 3

Give 2 examples of when diffusion happens in the body?

Answer 3

-Gas exchange in the lungs
-Nutrient absorption in the gut

Question 4

Describe how diffusion occurs in the lungs?

Answer 4

-Oxygen enters the lungs when you breathe in.
This oxygen needs to get into the blood so it can be carried around the body to where it is needed.
Oxygen passes into the blood from the lungs by diffusion.
-Humans also need to remove carbon dioxide from their body. This diffuses from the blood to the lungs to be breathed out.
- The process of exchanging oxygen and carbon dioxide between the blood and lungs is called gas exchange.

Question 5

Describe how nutrients are absorbed in the gut through diffusion?

Answer 5

-Food enters the body through the mouth and moves through the digestive system.
-When it reaches the small intestine the nutrients from the food are absorbed into the blood.
-The small molecules move into the blood by diffusion.

Question 6

Give three factors that can affect the rate (speed) of diffusion?

Answer 6

1. Temperature – The higher the temperature the faster the rate of diffusion.
2. Distance – The shorter the distance the faster the rate of diffusion.
3. Concentration gradient – The larger the concentration gradient the faster the rate of diffusion.

Question 7

What is meant by concentration gradient?

Answer 7

The difference between the number of particles in one area compared to another.