Biology test 2

all cells are surrounded by cell membrane

plasma membrane is phospholiped bilayer

plasma membrane

integral proteins

Peripheral Proteins

mosaic pattern

based on changing location and pattern of proteins in a fluid phospholipid bilayer

are carbohydrates attached to phospholipids

Glycoproteins

there are Five

proteins combines with molecules or ions and transports them across membrane

glycoproteins that help body defend itself against disease

form a channel through membrane to allow specific molecule or ion to cross membrane

proteins that catalyze specific reaction in membrane

proteins in membrane that bind to specific substance and alter cell metabolism

sec2

membrane

Membrane is differentially permeable

it allows some molecules to pass but not others Those substances that cannot pass through membrane may be transported by carrier proteins or may cross through channel proteins

Energy NOT required

Active Transport, Exocytosis, Endocytosis – Energy IS required

movement of molecules from place of higher concentration to place of lower concentration

diffusion

homogeneous mixture of two or more substances; often consists of liquid solvent in which solute is dissolved; solute will NOT settle out of solvent

it is the diffusion of water across semi-permeable membrane because of concentration differences (concentration of solute is higher on one side of membrane than on other side

solution concentration is the same on both sides of membrane; therefore, no net movement of water across membrane; cell volume remains the same

solution concentration outside cell is higher than inside concentration; cell shrinks by losing water

solution concentration outside cell is lower than inside cell; cell swells because of water uptake; cell may undergo cytolysis

bursting of cell due to uptake of water

Some proteins in membranes transport molecules across membranes

no energy required; moves molecules from higher to lower concentration

energy is required; moves molecules from lower concentration to higher concentration; uses carrier molecules in membranes

process by which intracellular vesicle fuses with membrane so that contents of vesicle released outside cell

process by which substances moved into cells by phagocytosis or pinocytosis or receptor-mediated endocytosis