Flashcards in Biology II Deck (58)
What is the cell membrane responsible for?
1. Regulate movement into and out of cell
2. Separate cell from its environment
What is the Phosolipid Bilayer?
The cell membrane; often referred to as the Fluid Mosaic Model
What is the Phosolipid Bilayer made of?
Phosphate and Fatty Acids
What is the membrane's permeability?
Selectively permeable or semi-permeable
What is passive transport?
Movement of molecules with the concentration gradient; does not use energy; includes diffusion, osmosis and facilitated transport;
What is the concentration gradient?
Difference in concentration in two or more areas
What is diffusion?
Movement of molecules is in any direction, but the net movement will be from areas of high concentration to areas of low concentration; molecules speed up when heated; will stop when equilibrium is reached
What is equilibrium?
When the concentration is equal; dynamic equilibrium;
What factors affect diffusion?
Temperature; size; steepness or difference in concentration gradient; distance; polarity
What is Active Transport?
Moving molecules against the concentration gradient; using energy.
What are the 3 proteins involved in plant transport?
1. Carrier proteins (Passive)
2. Channel proteins (Passive)
3. ATP (Active)
What is a carrier protein?
a protein present in cell membrane that binds to a specific molecule and transports it through the membrane
What is a channel protein?
a protein in the cell membrane that forms a passage way through which specific solutes can pass by diffusion; some channels open and close in response to binding of specific molecules
What is osmosis?
The diffusion of water
What is hypertonic?
higher concentration of solute
What is hypotonic?
higher concentration of solvent
What is isotonic?
Equal concentrations; dynamic equilibrium
firm; plant cells become turgid when water enters due to a hypertonic surrounding environment
Shrinking of the cytoplasm and plasma membrane away from the cell wall due to outflow of water in a hypertonic environment; observed only in cells with rigid cell walls
A type of membrane which allows certain particles to pass through while others are excluded; can be natural or synthetically produced for industrial use
uptake of particles or molecules by formation of a vesicle from the cell membrane; requires energy from ATP
Release if molecules from vesicle that fuses with the cell membrane to export the molecules from the cell; requires energy from ATP
Structure and to allow CO2 to pass easily
Anything can flow in or out freely
Pressure exerted against a cell wall by the water that has entered the cell through osmosis
What are the benefits for a cell to have a large surface area?
More area to absorb nutrients, small volume means that things reach the nucleus faster
directional growth in response to light
growth away from a light source
growth towards a light source