Transport Across the Membrane Flashcards
(32 cards)
Explain Hydrophobic
-Non-polar
Means fearing water
e.g the fatty acid tails in the cell membrane are non-polar
Explain Hydrophilic
- Polar
- Means water loving
e. g the phosphate heads are hydrophobic in the cell membrane
Define Active Transport
The movement of molecules from a region of low concentration to a region of high concentration, requiring the energy in the form of ATP.
Define the Fluid Mosaic Model
A phospholipid bi-layer studded with large proteins.
Explain a glycoproteins role
Cellular recognition (self or non-self) and signalling molecules
Explain a glycolipids role
They are receptors and markers and are essentially carbohydrate rings bonded to a lipid.
Impact of a hypertonic solution on a cell.
Loose water, animal cells will become shrivelled and plant cells will undergo plasmolysis
Impact of hypotonic solution on a cell
Gain water, animal cells will expand and can lyse (burst). Plant cells expand however the cell wall prevents it from rupturing.
Impact of an isotonic solution on a cell
No net movement, doesn’t gain or loose water
Define a hypertonic solution
Has a higher solute concentration than the solution it is compared with. (Cell will loose water)
Define a hypotonic solution
Has a lower solute concentration than the solution it is being compared with (Cell will gain water)
Define an Isotonic solution
Has the same solute concentration as the solution being compared with.
Examples of molecules that can pass through a membrane via simple diffusion.
Alcohol and steroids (non-polar)
H2O, gases, urea, (small polar)
Explain the Fluid Mosaic Model
Cell membranes consist of a bi-layer of phospholipids with embedded proteins floating throughout.
Define Osmosis
The passive net movement of water molecules from a region of low solute concentration to a region of high solute concentration, through a semi-permeable membrane.
Define a Simple Diffusion
The passive net movement of molecules across a semi-permeable membrane from areas of high concentration to areas of low concentration.
Define Facilitated Diffusion
The passive net movement of molecules across a semi-permeable membrane, via protein channels or protein carriers. The molecules, are moving from areas of high concentration to areas of low concentration.
Define Solute
The solute is dissolved into the solvent
e.g the salt in the saline solution
Define Solvent
The substance that the solute gets dissolved into
e.g the water in the saline solution
Define Solution
A mixture in which the solute evenly distributed throughout the solvent
Explain carrier proteins
Upon binding with a SPECIFIC molecule, carrier proteins create an opening in the lipid bi-layer by undergoing a conformational change, thus enabling the larger and more polar molecules to exit.
Define Bulk Transport
Vesicle mediated active transport that involves the movement of large particles across the cell membrane.
What type of substances use facilitated diffusion.
They are too large
- polar
- uncharged
What are the factors affecting permeability
Temperature, state of substance, surface area and composition of a membrane.
