Cells Flashcards
Cytoplasm
Liquid gel in which most chemical reactions take place
Cell-membrane
Selectively permeable, allows movement of materials into and out of cell
Cell wall
Support and protection of plant cell, e.g. Stops from bursting when turgid
Mitochondria
Powerhouse of cell, makes ATP
Ribosomes
Production of proteins
Chloroplasts
Use light energy in PS
Permanent vacuole
Stores food, water and waste in plants
Difference between animal and plant cells
Plant has cell wall, permanent vacuole and chloroplasts. Human cell does not. Animal cells round, plant cells rectangular
What is diffusion?
Movement of gases or dissolved molecules from area of high concentration to low concentration. Only things of a certain size can et though as cell membranes selectively permeable
What factors effect rate of diffusion?
- concentration gradient: the steeper the gradient, the faster the diffusion
- diffusion distance: greater the diffusion distance, slower it is
- SA: greater SA= faster ate of diffusion
- temperature: higher temp = after rate of diffusion as particles have more energy
What is facilitated diffusion?
Movement of molecules from high concentration to low concentration using a channel or carrier protein, e.g. Glucose or amino acids
What is active transport?
Movement of molecules through a membrane AGAINST a conc grad. Needs energy and sometimes a carrier protein
What is osmosis?
Movement of water molecules across a semi permeable membrane from an area of low concentration to high concentration, to equalise the water content
What happens in plant/animal cells when water leaves?
Plant: cytoplasm doesn’t push against cell wall, cell becomes plasmolyzed
Animal: same thing but no cell wall to hold it together ∴ cell itself shrinks
What happens in plant/animal cells when water enters?
Plant: cytoplasm and vacuole swell ∴ cell turgid
Animal: cell can hold a bit of water, but if the cell swells too much it can burst, as no cell wall
