Chapter 7 Vocabulary Flashcards
Selective Permeability
Allows some substances to cross it more easily than others
Amphipathic Molecule
A molecule with both a hydrophobic region and a hydrophillic region.
Fluid Mosaic Model
The membrane is a fluid structure with a “mosaic” of various proteins embedded in or attached to a double layer of phospholipids.
Integral proteins
Penetrate the hydrophobic core of the lipid bi-layer, usually trans-membrane proteins
Peripheral proteins
Loosely bound into the membrane, usually connected to the exposed parts of integral proteins.
Cell recongnition
A cell’s ability to distinguish one type of neighboring cell from another. It is crucial to the functioning of an organism. Glycolipids and glycoproteins are involved in this process.
Glyco-
Used to refer to the prescence of carbohydrates
Glycolipids
When a carbohydrate is covalently bonded to a lipid or lipids.
Glycoproteins
When a carbohydrate is covalently bonded to a protein or proteins.
Transport Protein
Function by having a hydrophilic channel that certain molecules or atomic ions can use as a tunnel through the membrane
Aquaporins
Channel proteins that allow water to pass through
Carrier Proteins
Hold onto their passengers and change shape in a way that shuttles them across the membrane.
Diffusion
The tendency for molecules of any substance to spread out evenly into the available space. The molecules will continue to spread across the membrane until both solutions have equal concentrations. From more concentrated to less concentrated.
Concentration Gradient
A measurement of how the concentration of something changes from one place to another
Passive transport
The diffusion of a substance across a membrane without the use of energy.
Hypo-tonic solution
Less salinity, causes the cell to swell
Hyper-tonic solution
More salinity, causes the cell to shrink
Osmosis
The movement of water across a selectively permeable membrane is called osmosis.
Tonicity
The ability of a solution to cause a cell to gain or lose water.
Osmoregulation
The control of water balance
Turgid
firm
Flaccid
Limp
Plasmolysis
The cell loses water to its surroundings and shrinks. In a plant, the membrane pulls away from the wall and causes the plant to wilt.
Facilitated Diffusion
Molecules and ions pass through the lipid bi-layer with the help of transport proteins with the concentration gradient.
Gated channels
A stimulus causes them to open or close, the stimulus can be electrical or chemical.
Active Transport
To transport a molecule against the concentration gradient. This requires energy.
Sodium-Potassium Pump
Exchanges sodium(Na+) for Potassium(K+) across the plasma membrane of animal cells.
Voltage
Electrical potential energy- a separation of opposite charges
Membrane Potential
The voltage across the membrane.
Electrochemical Gradient
The combination of forces acting on an ion.
Electrogenic Pumo
A transport protein that generates voltage across a membrane.
Proton Pump
Actively transports H+ out of the cell. The pumping of H+ transfers positive charge from the cytoplasm to the extra-cellular system.
Exocytosis
In exocytosis, transport vesicles migrate to the plasma membrane, fuse with it, and release their contents.
Endocytosis
Molecules enter cells within vesicles that pinch inward from the plasma membrane. There are three types: phagocytosis, pinocytosis, and receptor-mediated endocytosis.
Ligands
A general term for any molecule that binds specifically to a receptor site of another molecule. A complex of a lipid and a protein.
