Endosymbiosis

Question 1

Define diffusive flux and diffusion rate including the units.

Answer 1

Diffusive flux is the number of molecules per unit area per time that are diffusing. Units are molecules
/ cm2 / sec
Diffusion rate is the number of molecules per time that are diffusing. Units are molecules / sec

Question 2

Give an equation that relates the two.

Answer 2

Diffusion rate = diffusive flux * area across which molecules diffuse.

Question 3

What biological factors would increase both diffusive flux AND diffusion rate?

Answer 3

Both will increase if the concentration gradient increases. This occurs for:
Increasing concentration difference, C
Decreasing concentration distance x
Although increasing the diffusion coefficient increases both, this is usually not something an
organism can vary.

Question 4

What factor would only affect diffusion rate?

Answer 4

Only diffusion rate depends on the area.