All Flashcards
What is the effect of a high concentration of glucose outside a cell?
Glucose will move into the cell down its concentration gradient via facilitated diffusion (if appropriate membrane proteins are present).
What happens if a cell is placed in a hypotonic solution?
Water will move into the cell via osmosis, potentially causing it to swell or burst.
What is the effect of inhibiting the sodium-potassium pump?
The electrochemical gradient across the cell membrane will be disrupted, affecting nerve and muscle cell function.
What happens when gated ion channels open?
Specific ions flow across the membrane down their electrochemical gradient, changing the membrane potential.
What is the effect of increasing the number of aquaporins in a cell membrane?
The rate of water transport across the membrane increases.
Define passive transport.
Movement of molecules down their concentration gradient, from high to low concentration, without energy expenditure (ATP).
What is facilitated diffusion?
Passive transport that uses membrane proteins (channel or carrier proteins) to help molecules cross the cell membrane down their concentration gradient.
Define channel proteins.
Membrane proteins that form a hydrophilic channel through the membrane, allowing specific molecules or ions to pass through.
What are carrier proteins?
Membrane proteins that bind to a molecule, change shape, and release the molecule on the other side of the membrane, facilitating its transport.
What is active transport?
Movement of substances against their concentration gradient (from low to high concentration), requiring energy (ATP).
Define primary active transport.
Active transport that directly uses ATP to move molecules against their concentration gradient.
What is secondary active transport?
Active transport that uses the energy of an existing concentration gradient (created by primary active transport) to move another substance against its gradient.
Define aquaporins.
Channel proteins specifically designed for the rapid transport of water across the cell membrane.
What is a concentration gradient?
The difference in concentration of a substance across a space. Substances tend to move from where they are more concentrated to where they are less concentrated to balance the concentrations.
Compare and contrast simple diffusion and facilitated diffusion.
Simple Diffusion: No protein required, moves down concentration gradient. Facilitated Diffusion: Requires protein (channel or carrier), moves down concentration gradient. Both: Passive transport, no ATP needed.
What are the key differences between channel proteins and carrier proteins?
Channel Proteins: Form a pore, faster transport, less specific. Carrier Proteins: Bind to molecule, slower transport, more specific, conformational change.
Compare primary and secondary active transport.
Primary Active Transport: Uses ATP directly. Secondary Active Transport: Uses energy from an existing ion gradient. Both: Move substances against their concentration gradient.
Compare and contrast passive and active transport.
Passive Transport: Moves down concentration gradient, no ATP needed. Active Transport: Moves against concentration gradient, requires ATP.
Differentiate between facilitated diffusion and active transport.
Facilitated Diffusion: Passive, moves down concentration gradient, uses membrane proteins. Active Transport: Requires ATP, moves against concentration gradient, uses membrane proteins.