Lecture Quiz 2 Flashcards
(71 cards)
Phospholipid Bilayer
Hydrophobic tails on the inside, hydrophilic phosphate heads on the outside. Interspersed with cholesterol and proteins.
Membrane Proteins (2)
Integral Proteins
Peripheral Proteins
Integral Proteins
Embedded in the membrane, either fully or partially.
Transmembrane Protein
A type of integral protein that goes all the way through the membrane.
Peripheral Proteins
Loosely associated with the membrane (just stuck on the top like a gumdrop on top of a cupcake).
Membrane Protein Functions (6)
Ion Channels Transporters Receptors Enzymes Cell-Identity Markers Anchoring Proteins (linkers)
Ion Channels
Allows a specific molecule (like K or Na) to move down a gradient (from areas of high concentration to areas of low concentration).
Transporters
Carries solute across a membrane. Can be active or passive.
Receptors
Cause intracellular change when a ligand binds to the receptor site. A ligand is anything that bonds to a receptor.
Enzymes
Catalyzes a reaction.
Cell-Identity Markers
Identifies the cell as self (so immune doesn’t attack itself).
Anchoring Proteins (linkers)
Joins the cells to one another
Concentration Gradient
Things can move from high to low on the concentration gradient until equilibrium (or close to it)
Electrochemical Gradient
In which there is a difference in charge across the membrane in addition to a difference in concentration.
Active Transport
Solutes move against their concentration gradient, which requires the use of ATP. Small non polar molecules can move through the membrane on their own. Small lipids (such as steroids), O2, CO2, large molecules, ions, or polar molecules cannot get through.
Passive Transport
Solutes move down their concentration gradient, no ATP needed. Diffusion, Membrane/Ion Channels, Osmosis, and Facilitated diffusion are examples of this.
Diffusion
O2 moving down its concentration gradient, directly through the membrane.
Membrane/Ion Channels
Highly specific, only for one type of ion! Move from an area of high concentration to an area of low concentration until equilibrium.
Osmosis
Instead of solutes moving, water moss. Osmotic pressure is a pressure due to water because solutes are not moving through a selectively permeable membrane. Isotonic solution is equal, hypotonic solution blood cells burst, and hypertonic solution blood cells shrivel.
Facilitated Diffusion
A very specific solute binds on a carrier protein, releases to the inside of the cell, then changes shape and opens to the outside again.
Primary Active Transport
Sodium Potassium Pump is an example. 3 Na+ enter inside the cell, then are released to the outside using ATP. Then 2 K bind to the site while open to the outside, so there is no ATP required to get K in to the cell.
Secondary Active Transport
Uses ATP indirectly via symporters. Glucose and Sodium both bind, the pump changes shape, and both move in with no ATP. The cell doesn’t want the sodium, so it goes to the sodium potassium pump, which uses ATP to remove sodium from the cell. Thereby, this uses ATP indirectly to bring glucose into the cell, because glucose cannot get in unless sodium comes too.
Vesicular Transport
Vesicles come in as a small sac that comes off the membrane.
Endocytosis
The cell bringing things in.
