| A | B |
|---|
| Concentration gradients tend to eventually | even out |
| Diffusion eliminates concentration gradients as long as there isn't a _____________ | membrane that might restrict or block flow |
| When different solute concentrations exist on either side of a selectively permeable membrane, _______ moves water through the membrane to equalize the concentration gradients | osmosis |
| Carrier-mediated transport of ions and organic substrates--tell more about the kind oftransports | facilitated diffusion & active transport, inc secondary active transport |
| Characteristics of Carrier-Mediated Transport | Specificity,Saturation limits,Regulation |
| Characteristics of Carrier-Mediated Transport- Specificity | 1 transport protein, 1 set of substrates |
| Characteristics of Carrier-Mediated Transport- Saturation limits | rate depends on transport proteins, not substrate |
| Characteristics of Carrier-Mediated Transport- Regulation | cofactors such as hormones |
| cotransport | 2 substances move in the same direction at the same time |
| Countertransport | 1 substance moves in while another moves out |
| Facilitated diffusion is both | Passive and carrier mediated |
| Carrier proteins transport-- | molecules too large to fit through channel proteins (glucose, amino acids): |
| 3 steps of carrier protein transport | 1)molecule binds to receptor site on carrier protein 2)protein changes shape, molecules pass through 3) receptor site is specific to certain molecules |
| Active transport proteins | move substrates against concentration gradient ---require energy, such as ATP |
| Sodium-Potassium Exchange Pump - Active transport, carrier mediated | moves sodium ions (Na+) out, potassium ions (K+) in |
| Endocytosis (endo = into) | Endocytosis (6/7) (endo = into) active transport using ATP: receptor-mediated pinocytosis phagocytosis |
| exocytosis (exo = out of) | Exocytosis is the reverse of endocytosis |
| exocytosis | Receptors bind target molecules - Coated vesicle carries ligands and receptors into the cell |
| Pinocytosis (cell drinking) | Endosomes “drink” extracellular fluid |
| Phagocytosis (cell eating) | engulfs large objects |
| chromatin | long strands of DNA and proteins found in the nucleus; condense to form chromosomes |
| Mitosis | divides genetic material equally |
