What is diffusion? Flashcards
The movement of molecules from an area of higher concentration to an area of lower concentration until equilibrium is reached. (19 cards)
What is diffusion?
The movement of molecules from an area of higher concentration to an area of lower concentration until equilibrium is reached.
What is osmosis?
The diffusion of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
What is facilitated diffusion?
A type of passive transport where molecules move down their concentration gradient through a protein channel or carrier protein in the cell membrane.
What is active transport?
The movement of molecules across a membrane against their concentration gradient, requiring energy in the form of ATP.
What is the sodium-potassium pump?
A type of active transport that moves 3 sodium ions out of the cell and 2 potassium ions into the cell using ATP.
What is endocytosis?
A process where the cell membrane engulfs substances to bring them into the cell, forming a vesicle.
What are the two types of endocytosis?
- Phagocytosis: Cell eating – ingestion of large particles or cells.
- Pinocytosis: Cell drinking – ingestion of liquids or small solutes.
What is exocytosis?
A process where vesicles fuse with the cell membrane to release substances outside the cell.
What is passive transport?
The movement of substances across a cell membrane without the use of energy (ATP), including diffusion, osmosis, and facilitated diffusion.
What is the difference between hypertonic, hypotonic, and isotonic solutions?
Hypertonic: Higher solute concentration outside the cell; water moves out, and the cell shrinks.
Hypotonic: Lower solute concentration outside the cell; water moves in, and the cell swells.
Isotonic: Equal solute concentration; no net movement of water.
What is the role of transport proteins?
They assist in the movement of substances across the cell membrane, either passively (facilitated diffusion) or actively (active transport).
What is the fluid mosaic model?
A model describing the cell membrane structure, where the membrane is flexible (fluid) and made of various molecules like lipids, proteins, and carbohydrates (mosaic).
What are aquaporins?
Specialized protein channels in the cell membrane that facilitate the rapid movement of water molecules.
What is bulk transport?
The movement of large molecules or large quantities of molecules across the cell membrane via vesicles, including endocytosis and exocytosis.
What is plasmolysis?
The process where a plant cell loses water in a hypertonic solution, causing the cell membrane to pull away from the cell wall.
What is the role of ATP in active transport?
ATP provides the energy needed to move molecules against their concentration gradient in active transport.
How does the concentration gradient affect diffusion?
The steeper the concentration gradient, the faster the rate of diffusion, as molecules naturally move from higher to lower concentrations.
What are vesicles, and how are they involved in cellular transport?
Vesicles are small, membrane-bound sacs that transport substances within a cell or between the cell and its surroundings, such as during endocytosis and exocytosis.
How do large molecules like glucose cross the cell membrane?
Large molecules like glucose cross the membrane through facilitated diffusion using specific carrier proteins or, in some cases, active transport when energy is needed.
