3. Membrane
- Barrier between each cell and its environment
- Partition of the cytoplasm into compartments
* Nucleus
* organelles
- All biological membranes have much in common
• Fluid bilayer of lipid molecules
• Integral membrane proteins
• Pheripheral membrane proteins
19. Pump : enzymes that utilize energy from ATP or light or other sources to movie ions and
other solutes across membranes
- Formation of gradients expense of chemical energy
- Convert chemical energy to electric energy
Carrier : enzyme-like proteins provide passive pathway for solute to move across membranes
- From higher concentration and lower concentration
- Carriers uses ion gradient as a source of energy
Channel : ion-specific pores which can open and close transiently
- Channel open : ion passes quickly across membrane
- Channel close : stop
- Movement of ions through channel is basis of control of electric potential across mebrane
20.
21. Light-driven Proton Pump : Bacteriorodopsin
Convert Light energy as chemical energy (Formation of proton gradients)
25. P-Type Cation Pumps : Ca2+-ATPase (SERCA1)
Ca2+ acts as important second messenger in cells
Therefore, Ca2+ concentrations should be
Pumps Ca2+ out of cytoplasm into the endoplasmic reticulum
26.
27.
28.
29.
30. Carrier : enzyme-like proteins provide passive pathway for solute to move
across membranes
- From higher concentration and lower concentration
- Carriers uses ion gradient as a source of energy
31.
32. - Uniproters
GLUT carrier for glucose
- Antiporters
Driving ion moves in one direction, then drive substrate in the others
- Symporters
ion and substrates goes to the same directions
33. Channels
Channel : integral membrane proteins with transmembrane pores that allow particular
ions or small molecules
34.
35.
36. Selectivity filter of Ion Channel
Potassium (K+) channel should allow pass-through of Potassium, but Sodium
37.
38.
39.
40.
41.
42.
43. Voltage-gated K+ Channel
- voltage-gated K+ and Na+ channels produce action potentials in excitable cells
54. Cooperation of Channel, Pump and Carrier in Cell
1. Chemical Energy from ATP was converted as concentration gradients of C+
2. Carrier uses electrochemical gradient of C+ to drive transport C+ and S