Diffusion

Question 1

What is diffusion?

Answer 1

Diffusion is the net movement of particles from an area of high concentration to an area of low concentration until they have spread out equally

Question 2

Diffusion moves… (gradient)

Answer 2

Diffusion moves down a concentration gradient

Question 3

Transport?

Answer 3

Passive process

Question 4

Substances that can pass through the cell membrane by diffusion?

Answer 4

Oxygen, Carbon Dioxide, Glucose

Question 5

Four factors affecting the rate of diffusion?

Answer 5

Concentration gradient, Surface area to volume ratio, Temperature, Distance

Question 6

How are organisms adapted for faster diffusion?

Answer 6

Large surface area, larger the surface area, the higher the number of particles will be able to move in a given time. The walls of the blood capillaries are only one cell thick, making it easier for diffusion to take place

Question 7

How do you work out the SA:VOL ratio?

Answer 7

Area of cube= 6(widthlength)
Volume of a cube= widthlengthheight

Question 8

How does the SA:VOL ratio affect the rate of diffusion?

Answer 8

The higher the SA:VOL ratio, the faster the rate of diffusion

Question 9

Explain the effect of SA:VOL ratio on the rate of diffusion. How is this important in living organisms?

Answer 9

Rate of diffusion is enough to meet the needs of a single celled organism but not a multicellular organism. Therefore we can not rely on diffusion alone.

Question 10

Ways to increase SA:VOL ratio…

Answer 10

-Long/thin shape
-Folding the surface of the object/cell membrane e.g. villi of the lining of the small intestine
-Plant cells are much larger than animal cells and they have a large vacuole which pushes the organelles to the edge of the cell where they get regular access to resources