5.3 Diffusion

Question 1

What is passive transport?

Answer 1

Transport of molecules

which does not require energy from cellular respiration

Question 2

What is diffusion?

Answer 2

net movement of particles

from a region of high to low concentration

Question 3

What factors affect the rate of simple diffusion?

Answer 3

• TEMPERATURE
  
  • Higher temperature = ￪ E_k = ￪ rate of diffusion
• CONCENTRATION GRADIENT
  
  • steeper concentration gradient = ￪ rate of diffusion

Question 4

What is simple diffusion?

Answer 4

Diffusion of particles

without the use of membrane proteins

Question 5

What is a partially permeable membrane?

Answer 5

a membrane

which allows some types of molecules through but not others

(selective)

Question 6

What factors affect the rate of diffusion across membranes?

Answer 6

• TEMPERATURE
  
  • Higher temperature = ￪ E_k = ￪ rate of diffusion
• CONCENTRATION GRADIENT
  
  • steeper concentration gradient = ￪ rate of diffusion
• SURFACE AREA
  
  • larger surface area = ￪ rate of diffusion
• MEMBRANE THICKNESS
  
  • thinner membrane = ￪ rate of diffusion

Question 7

In addition to temperature, concentration gradient, surface area & membrane thickness, what other factor affects the rate of facilitated diffusion?

Answer 7

number of channel proteins available