Pumps, Carriers, Channels Flashcards
Are pumps primary or secondary transporters?
Primary
What is the typical rate of transport for a pump in ions per second?
100
Protein pumps transport solutes _ their concentration gradient
Up
How do pumps drive a variety of biochemical processes?
They store energy in the form of transmembrane electrochemical gradients
Most pumps translocate _
Cations. They were selected for very early in the evolution of life
What are the tree main families of pumps?
ATPases, ABC, and rotary ATPases
What limits the concentration gradient that can be generated by pumps?
The amount of free energy released in the hydrolysis of ATP
What 3 sources provide energy for pumps?
light, hydrolysis of ATP, reduction-oxidation reactions
Carriers are _ membrane proteins that provide _ pathways for solutes to move across membranes
Integral, passive
How do conformational changes in carrier proteins cause translocation of small molecules across membranes?
The binding site for subtrates changes side, substrate is released
Are carriers primary or secondary transporters?
Secondary
What limits the rate of flow acorss the membrane via carrier proteins?
The speed at which conformational changes can occur
What determines the rate of translocation by a carrier protein?
The concentration of substrates on either side of the membrane
Why is net movement of substrates downhill for carrier proteins?
Binding sites are more readily occupied on the side of highest concentration
Antiporters usually exchange _ substances
Like for like
eg. cation for cation, sugar for sugar
