Simple (Passive) Diffusion
Describe the direction of transport relative to theconcentration gradient:
Molecules move down a concentration gradient. They movefrom region of higher concentration to one of lower concentrationbecause of random thermal agitation.
Describe where the energy for transport comes from:
No metabolic energy input is required.
Describe IF and HOW membrane proteins participate:
No membrane proteins are used for this transport.
Discuss whether or not this type of transport offers the cellspecificity. i.e., can the cell regulate what goes in andout?:
Does not regulate the cell specificity.
Facilitate Diffusion
Describe the direction of transport relative to theconcentration gradient:
Molecules move down a concentration gradient. They movefrom region of higher concentration to one of lowerconcentration.
Describe where the energy for transport comes from:
No metabolic energy input is required.
Describe IF and HOW membrane proteins participate:
Uses carrier molecules (permeases) by attachment.
Discuss whether or not this type of transport offers the cellspecificity. i.e., can the cell regulate what goes in andout?:
The membrane carrier can change conformation after binding onexternal molecule and subsequently release the molecule on the cellinterior.
Primary Active Transport
Describe the direction of transport relative to theconcentration gradient:
Movement of ions or molecules across a cellular membrane from alower to a higher concentration.
Describe where the energy for transport comes from:
ATP, sunlight, etc.
Describe IF and HOW membrane proteins participate:
Involves carrier proteins (permeases) by attachment.
Discuss whether or not this type of transport offers the cellspecificity. i.e., can the cell regulate what goes in andout?:
Concentrates molecules inside the cell.
Secondary Active Transport
Describe the direction of transport relative to theconcentration gradient:
Molecules move against the gradient. They move from low tohigh concentration.
Describe where the energy for transport comes from:
ATP, sunlight, etc.
Describe IF and HOW membrane proteins participate:
Attaches to a carrier protein.
Discuss whether or not this type of transport offers the cellspecificity. i.e., can the cell regulate what goes in andout?:
Concentrates molecules inside the cell.