Cell Transport Mechanisms Flashcards
What is diffusion?
The movement of particles down a concentration gradient, they move from a high concentration to a low concentration
What is facilitated diffusion?
Diffusion that takes place through carrier proteins or protein channels
What is osmosis?
A type of diffusion that involves the movement of water molecules down a concentration gradient through a semi-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 using ATP
What is an isotonic solution?
Normal cells, the osmotic concentration of the solutes is the same as the cells
What is a hypertonic solution?
Shrivelled cells where the water has left, the osmotic concentration of the cells is lower than in the solutes
What is a hypotonic solution?
The cells swell and eventually burst, the osmotic concentration in the solutes is lower than in the cells
What does turgid mean?
Hard, swollen (hypotonic cells)
What does flaccid mean?
Space between vacuole and cell wall (isotonic cells)
What is water potential?
A measure of the potential of water to move out of a solution by osmosis
What is turgor?
The state of a plant cell when the solute potential causing water to be moved into the cell by osmosis is balanced by the force of the cell wall pressing on the protoplasm
What is plasmolysis?
When a plant cell is placed in hypertonic solution when so much water leaves the cell by osmosis that the vacuole
What is the calculation for water potential?
Turgor pressure + osmotic potential
What factors affect active transport?
-Temperature
-pH levels
-Concentration gradients
-Availability of ATP
What is phagocytosis?
A form of active transport where a cell engulfs something relatively large e.g a bacterium and encloses it as a vesicle
What is pinocytosis?
A form of active transport where cells take tiny amounts of extracellular fluid into vesicles
What is turgor pressure?
The pressure generated as the swelling protoplasm pushes against the cell wall in plants
What is a carrier protein?
Proteins which move a substance through the membrane in active transport
What is pressure potential?
A measure of the inward pressure exerted by the plant cell wall on the protoplasm of a cell opposing the entry of water by osmosis
What is passive transport?
Transport that takes place as a result of concentration, pressure or electrochemical gradients and involves no energy from a cell
What are the differences between passive transport and active transport?
-Passive transport diffuses from high to low
-Passive transport includes osmosis
-Passive transport requires no energy
-Active transport includes engulfing a transport protein
-Active transport diffuses low to high
-Active transport requires energy
What is the definition of osmosis about water potential?
The net movement of water molecules from an area of higher water potential to an area of lower water potential through a partially permeable membrane
