1 / 8

Passive and Active Transport

7b. Passive and Active Transport. Passive Transport. Diffusion across a membrane, no ___________. Diffusion: tendency to spread out, move from ____ concentration to ____ concentration. Any substance will diffuse down its __________ ____________. Osmosis.

nikki
Download Presentation

Passive and Active Transport

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 7b Passive and Active Transport

  2. Passive Transport • Diffusion across a membrane, no ___________. • Diffusion: tendency to spread out, move from ____ concentration to ____ concentration. • Any substance will diffuse down its __________ ____________.

  3. Osmosis • Diffusion of ____________ across a selectively permeable membrane • ____________: higher solute concentration outside the cell • ____________: lower solute concentration outside the cell • ____________: equal solute concentrations • Animal cells shrink in ____________, burst in _______________, stable in ______________. • Plant cells plasmolyzed in hypertonic, flaccid in isotonic, stable (turgid) in hypotonic

  4. Facilitated Diffusion • Diffusion aided by a transport ___________. • Proteins are specific, can be saturated and inhibited. Some change shape to let the molecule go through. Some provide a channel: • Gated channels: opened or closed by a stimulus • Chemical: • Voltage: • Ex. Cystinuria: disease characterized by absence of protein that transports cystine and other amino acids across a membrane of kidney cells, aa’s not being reabsorbed into blood, instead clump and crystallize. AKA ____________________________.

  5. Active Transport • Pumping against a concentration gradient, requires _______________! • Ex. Go through Na/K pump 3 Na pumped out, 2 K pumped in, net transfer of 1 + charge to ECM • Voltage: electrical PE, separation of opposite charges • Cytoplasm is negatively charged compared to ECM • Membrane potential: voltage across membrane -50 to -200 mV • Favors _________ into cell and ________ out of the cell. • Electrochemical gradient: 2 forces • Chemical: ions concentration gradient • Electrical: membrane potential Electrogenic pump: transport protein that generates voltage across a membrane.

  6. Proton Pump • Actively transports H+ out of the cell, + charge to ECM, stores energy

  7. Cotransport • ATP powered pump indirectly drives the active transport of other solutes

  8. Endo and Exocytosis • ___________: secrete macromolecules by fusion of the membranes • ___________: takes in macromolecules by forming new vesicles. • ____________: cell eating, cell engulfs particle and forms vacuole where digestion takes place • ____________: cell drinks droplet of extracellular fluid. • Receptor mediated: specific ligand binds receptor and is then engulfed. • Ex. Cholesterol enters by LDL receptors. HYPERCHOLESTEROLEMIA: LDL receptor is defective, buildup of cholesterol in blood  atherosclerosis

More Related