Chapter 3 Flashcards
Glycolipids
Lipids with attached sugar groups. Found only in the outer plasma membrane surface, Glycolipids account for about 5% of total membrane lipids
Hydrophilic
“Water loving”
Cholesterol
Some 20% of the membrane lipid is cholesterol. Like phospholipids, cholesterol has a polar and unpolar region
Diffusion
Tendency of molecules to move from an area where they are higher in concentration to an area of lower concentration
Simple diffusion
Nonpolar and lipid soluble substances, diffuse directly through the lipid bilayer
Facilitated diffusion
Certain molecules, notably glucose and other sugars, some amino acids, and ions are transported passively even though they are unable to pass through the lipid bilayer.
Osmosis
The diffusion of a solvent such as water through a selectively permeable membrane is osmosis
Isotonic solutions
Cells retain their normal size and shape in isotonic solutions. Same solute and water concentrations as inside cells. Water moves in and out
Hypertonic solutions
Cells lose water by osmosis and shrink in a hypertonic solution. Water moves out. Contains a higher concentration of salutes than are present inside the cells
Hypotonic
Cells take on water by osmosis until they become bloated and burst (lyse) in a hypotonic solution. Water moves in. Contains a lower concentration of solutes than are present inside cells
Hydrostatic pressure
The back pressure exerted by water against the membrane
Tonicity
Refers to the ability of a solution to change the shape or tone of cells by altering the cells internal water volume
Organelles
Are the metabolic machinery of the cell. Each type of organelle carries out a specific function for the cell
Mitochondria
Power cells. Providing ATP
Ribosomes
Synthesize proteins destined either for incorporation into cell membranes
