Mod 3 Flashcards
what factors affect the fluidity of cell membranes?
length, amount of c-c double bonds, and cholesterol
how does length affect fluidity?
the longer the fatty acid tail, the less fluid, and the shorter the fatty acid tail, the more fluid
how does presence of c-c double bonds affect fluidity?
higher presence increases fluidity, and smaller presence decreases fluidity
how does cholesterol affect fluidity?
higher the temperature, more fluid, lower the temperature, less fluid, and cholesterol acts as a buffer - buffer fluidity
what is the role of lipid rafts?
transport materials laterally through the cell membrane, it is able to move left and right
characteristics of the head of a phospholipid
polar, hydrophilic, contain glycerol, phosphate group, and polar group
characteristics of a the tail of a phospholipid
nonpolar, hydrophobic
what happens if the head of phospholipid is large and bulky, one hydrophobic tail is buried to form spheres called?
micelles
what happens if phospholipids are added to test tube of water, and form enclosed bilayers called?
lipsomes
cell membrane structure is made up of the following components:
proteins, lipids, carbohydrates
what are the different types of membrane proteins?
integral and peripheral
what is an integral protein?
permanent, span along entire lipid bilayer
what is an peripheral protein?
temporary, either cytoplasmic or extracellular
what are membrane carbohydrates?
glycoprotein, and glycolipid
fluid mosaic model meaning?
fluid - fluidity of cell membrane, and mosaic meaning mixture
what does it mean when plasma membrane is selectively permeable?
some molecules more permeable than others - gases, nonpolar molecules (lipids), small uncharged polar molecules.
macromolecules are too large to move across (proteins, carbohydrates)
what is movement into cells called?
influx
what is movement out of cells called
efflux
what is it called when one movement of substance exceeds the other?
net flux
what are the two mechanisms of passive transport?
simple diffusion, and facilitated diffusion
what is simple diffusion?
through cell membrane, small molecules and hydrophobic molecules are able to go through
what is facilitated diffusion?
contain two types of membrane transporters .. channel protein and carrier protein
molecules move through protein transporter
what is a channel protein?
formed by integral protein, permeable to specific molecules, have gated channel
what is carrier protein?
when molecule binds to carrier protein on one side of membrane - triggers conformational change
