Cell Bio

holds internal content of the cell separate from the outside and regulate what gets into and out of the cell. Water, gases (O2, CO2), small noncharged or non-polar molecules pass through NA+, large molecules like sugar cannot

• two layers of phospholipids, flexible structure describes a fluid mosaic model • cholesterol is an integral part of the cell membrane, is in the hydrophobic portion keeps the membrane flexible

associated with the membrane - some are external, some are on the inside, and some are transmembrane proteins (across) function 1) acting as receptors 2) channels or pumps for ions and other material to cross the membrane 3) signaling across the membrane

diffusion osmosis

the tendency of molecules to spread from areas of high concentration to areas of low concentration in order to reach equal concentration throughout- the process is driven by the concentration gradient

movement of water across a cell membrane from high concentration to low areas thing of salt

equal salt concentration inside and outside of cells

salt concentrations outside the cell are less than those inside the cell, water moves into the cell to reduce the internal salt concentration the cell will swell and may eventually burst

salt concentrations outside the cell are greater than those inside the cell. water moves out of the cell to increase the internal salt concentration, the cell will shrink

requires cellular energy

involves transmembrane protein acting as “pumps”- ATP is required - into the cell or “pumping out” materials such as ions to maintain unequal concentration such as K+ or Na+

bringing something into the cell across the membrane • Receptor-mediated endocytosis • phagocytosis • pinocytosis

the molecule binds to a receptor on the surface of the cell- that triggers the receptors and the material bound to it to be brought in through the cell membrane to the inside of the cell in a vesicle

cell engulfs solid material (white blood cells ingesting a bacteria)- bring it in through the cell membrane and breaks it down

cell engulfs and brings in liquid material

moving something in vesicle from the inside of the cell to be released to the outside

the fluid or gel inside the cell (cytosol) and the various organelles

very small made up of 2 circular subunits-found free in the cytoplasm or attached to the round endoplasmic reticulum the function is to make protein

a ‘stack’ of folded interconnected membranes-start at the edge of the nuclear membrane function- two type rough: covered with ribosomes=make protein smoot: make lipids

a series of stacked and folded membranes (similar to but smaller than the Er) function 1) adding sugars to the molecules 2) packaging material for movement to another part of the cell or release from the cell- the material is placed in a vesical and moved elsewhere within the cell or released by exocytosis

small, rounded, membrane-bounded structure function- contains digestive enzymes and other molecules- breaks things ingested by the cell

a membrane-bounded “bubble” within a cell that stores something (ex. food vacuole)

kidney-shaped- contain highly infolded internal membranes called cristae- this creates additional surface areas and are sites for cellular respiration to take place and the ATP synthase to function. They have their own DNA which is passed from mother to offspring function- production of ATP, cellular energy

specialized structure for carrying out photosynthesis- contains chlorophyll and membrane systems including the thylakoid membrane