뒤로Membrane Structure & Function -Lecture 4a-chapter 7-(page 36 to 71)(exam 2)
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In a hypotonic solution, animal cells lyse (burst). In an isotonic solution, they remain normal. In a hypertonic solution, they shriveled.
In hypotonic solution, plant cells become turgid (normal and firm). In isotonic, they become flaccid (limp). In hypertonic, they undergo plasmolysis where the membrane pulls away from the cell wall.
The contractile vacuole pumps excess water out of the cell to maintain water balance in hypotonic environments.
Channel proteins provide corridors for specific molecules or ions. Carrier proteins undergo shape changes to transport molecules across the membrane.
Aquaporins facilitate water diffusion. Ion channels facilitate ion transport, some of which are gated and open in response to stimuli.
They open or close in response to stimuli such as electrical signals or chemical binding, controlling ion flow.
Facilitated diffusion moves solutes down their concentration gradient without energy. Active transport moves solutes against their gradient using energy, usually ATP.
A carrier protein that uses ATP to pump Na+ out and K+ into animal cells, maintaining concentration gradients.
The voltage across a membrane created by differences in ion distribution, with the inside of the cell negative relative to outside.
The chemical force (ion concentration gradient) and the electrical force (membrane potential) together drive ion diffusion.
A transport protein that generates voltage across a membrane by moving ions, storing energy for cellular work.
In animals, the sodium-potassium pump. In plants, fungi, and bacteria, the proton pump that transports H+ ions out of the cell.
Active transport of one solute indirectly drives transport of another solute against its gradient by coupling their movements.
Proton pumps create an H+ gradient, and cotransporters use the downhill diffusion of H+ to actively transport sucrose into the cell.
They couple active transport of glucose to the diffusion of Na+ into intestinal cells, maintained by sodium-potassium pumps.
Rapid waste expulsion prevents sodium reabsorption, causing low sodium levels. Treatment involves drinking salt and glucose solutions to enable sodium/glucose uptake.
Transport vesicles fuse with the plasma membrane to release large molecules outside the cell, e.g., insulin secretion by pancreatic cells.
The process of taking macromolecules into the cell by forming vesicles from the plasma membrane.
Phagocytosis (cellular eating), pinocytosis (cellular drinking), and receptor-mediated endocytosis.
The cell engulfs particles by extending pseudopodia, forming a food vacuole that fuses with lysosomes for digestion.
Non-specific uptake of extracellular fluid and solutes into tiny vesicles lined with coat proteins.
Specific solutes bind to receptors clustered in coated pits, which form vesicles to bring solutes into the cell; receptors are recycled.