cell transport Flashcards
describe the structure of the plasma membrane and some of its characteristics.
it is a lipid bilayer with some proteins, it is composed of phospholipids
the membrane is semi permiable, which means it allows some things in a prohibits others.
what is phospholipid and how is it structured and used in the plasma membrane
a phospholipid is made up of phosphate and fatty acids, it contains a hydrophillic head which means it is water soluble, also is polar. also has a hydrophobic tail, which means it is fat soluble, non polar. there is two phospholipids to create the bilayer.
what are glycoproteins functions in the bilayer
MARKER, so cells can identify each other
RECEPTORS, chemical messages
REGULATORS, what enters and attaches to host cell.
TRANSPORTERS, carry certain materials in and out of cell
what may affect permeability (5)
- particle size
2.particle solubility - concentration, inside and outside of cell
4.electrical charge
5.membrane structure
what is passive transport, what gradient does it follow?
the movement of materials across cell membrane without the cell using its own energy. it flows with the concentration gradient.
what is simple diffusion (goals, what does it move)
random movement of substance from area of high concentration to area of low concentration. it helps establish equilibrium, it will move small, non polar molecules, like ions and gases.
what is osmosis
it is the diffusion of water, when water enters a cell pressure will occur inside, its goal is to maintain equilibrium
what are the three types of osmatic solutions, describe each
1.ISOTONIC, solute concentration in the cell is equal to the concentration outside, water flows in and out
2.HYPOTONIC, solute concentration is less outside the cell then it is inside, water flows in increasing the size of the cell, cells will under go cytolosis
3. HYPERTONIC. solute concentration is higher outside of the cell then it is on inside, water flows out, causes plasmolysis, dehydration or wilt.
what is facilitated diffusion
channel proteins speed up movement, it is very selective, used for glucose diffusion in red blood cells
what is active transport
movement of substances across cell membrane requiring the cell to use its own energy. will flow against the gradient
describe facilitated transport, and steps involved
type of protein pump, requires a protein carrier molecule to get a energy boost from ATP
1.protein pump specific to sub 1 based on shape
2. NRG closes and pushes sub 1 through the membrane
3. new shape on pump specific for sub 2 allows it to enter
4. release of phosphate causes pump to go back to old shape pushing sub 2 through membrane
what is endocytosis
movement of substance into the cell, it transports larger molecules
engulfs molecule and pseudopods close it until enclosed by vacuole
digested by enzymes
what are the two types of endocytosis, give examples
- PHAGOCYTOSIS, engulfs solid particles( amoeba, white blood cells)
- PINOCYTOSIS, engulfs liquid particles( cells in small intestine engulf fat droplets)
explain exocytosis
the movement of large molecules out of the cell, wastes and water stored in vacuoles, move to join and cell membrane to excrete the vacuoles content.
