Cell Transport Mechanisms Flashcards
What is diffusion?
The movement of particles in a liquid or gas down a concentration gradient
What is facilitated diffusion?
Diffusion that takes place through carrier proteins or protein channels
What is osmosis?
A specialised form of diffusion that involves the movement of solvent molecules (usually water) down a concentration gradient through a partially permeable membrane
What is endocytosis?
The movement of large molecules into cells through vesicle formation
What is exocytosis?
The movement of large molecules out of cells through vesicle formation
What is active transport?
The movement of substances across the membrane of cells directly using ATP
What makes up the fluid mosaic model?
Phospholipids, proteins and cholesterol
What is an isotonic solution?
Where the osmotic concentration of the solutes in the solution is the same as that in the cells
What is a hypotonic solution?
Where the osmotic concentration of solutes in the solution is lower than that in the cytoplasm of the cells
What is a hypertonic solution?
Where the osmotic concentration of solutes in the solution is higher than that in the cytoplasm
What is pressure potential?
The inward pressure of the cell wall on the cytoplasm
What does turgor mean?
When the plant cell is rigid and the pressure potential is forcing it out.
What is incipient plasmolysis?
When the plant cell membrane begins to pull away from the cell wall as the protoplasm shrinks due to being placed in a hypertonic solution resulting in water moving out of the cell by osmosis and the turgor is lost
What is the calculation for water potential?
Water potential of cell = turgor pressure (usually positive) + osmotic potential (always negative)
What is water potential?
A measure of the potential of water to move out of a solution by osmosis
