Workshop #7

Let me preface by saying, I lost my notes from this workshop, but since I agreed to be the scribe, I will do my best.

"Transport and ATP synthesis"

Passive transport

• with the concentration gradient
• bidirectional
• how it all goes down:
1. large molecule binds to an integral membrane protein
2. the bond causes a conformation change
3. conformation change causes the molecule to pass through the membrane (switches its side)
4. ready to repeat

Active transport

• against concentration gradient
• unidirectional (use this principle to determine what kind of transporter it is)
• how it all goes down:
1. large molecule binds to an integral membrane protein
2. ATP latches onto the IMP and releases a phosphate group
3. phosphorylation = big conformation change
4. conformation change causes molecule to pass through membrane
5. not ready to repeat until the IMP dephosphorylates

How is ATP made?

Creatine P + ADP -> Creatine + ATP
CP-> C is delta G -50kJ/mol
ADP -> ATP is delta G +30kJ/mol

Couple the reactions = spontaneous! delta G -20kJ/mol

made in an ATP synthase (aka an ion pump working in reverse)
times of large concentration gradients = make ATP
times of small concentration gradients = make bigger concentration gradient

New term of fun:
Iso-osmotic= same amount of stuff on each side and same amount of pressure on each side.