Quiz on pages 75-80 Flashcards
substance present in the largest amount in a solution
solvent
components or substances present in smaller amounts
solutes
a solution containing small amounts of gases (oxygen and carbon dioxide), nutrients, and salts, dissolved in water
intracellular fluid
the fluid that continuously bathes the exterior of our cells
interstitial fluid
means that a barrier allows some substances to pass through it while excluding others.
selectively permeable
what are the two types of passive transport
- diffusion (membrane transport for all body cell)
2. filtration (usually across capillary walls)
process by which molecules (and ions) move away from a region where they are more concentrated (more numerous) to a region where they are less concentrated (fewer of them)
diffusion
unnassisted diffusion of solutes through the plasma membrane (or any selectively permeable membrane)
simple diffusion
diffusion of water through a selectively permeable membrane such as the plasma membrane
osmosis
provides passage for certain needed substances (notably glucose) that are both lipid-insolable and too large to pass through the membrane pores (substances move down a channel of proteins that act as a carrier (concentration gradient)
facilitated diffusion
process by which water and solutes are forced through a membrane (or capillary wall) by fluid (or hydrostatic) pressure.
filtration
the gradient used for filtration. pushes the solute containing fluid (filtrate) from the higher-pressure area to the lower-pressure area.
pressure gradient
gradient used for passive transport. molecules move down the gradient. The greater the difference in concentration between the two areas, the faster the diffusion.
concentration gradient
what is the driving force in diffusion and what makes it go faster and slower?
kinetic energy; size (smaller the faster), temperature(warmer the faster)
When will molecules diffuse through the plasma membrane?
- molecules are small enough to ass through the membrane’s pores
- molecules are lipid-soluble
- molecules are assisted by a membrane carrier
process that requires a protein carrier that combines specifically and reversible with the substances to be transported across the membrane. The cell uses some of its ATP supply to move substances across the membrane.
active transport
protein carriers are also called..
solute pumps
simultaneously carries sodium ions (Na+) out of and potassium ions (K+) into the cell. necessary for normal transmissions of impulses by nerve cells
sodium-potassium pump (Na+ —K+)
uses ATP to move substances into or out of cells without actually crossing the plasma membrane
vesicular transport
what are the two types of vesicular transport
exocytosis and endocytosis
moves substances out of cells. cells actively secrete hormones, mucus, and other cell products or eject certain cellular wastes.
exocytosis
this is where the product to be released during exocytosis is first “packaged.” It then migrates to the plasma membrane, fuses with it, and then ruptures, spilling the sac contents out of the cell
vesicle
ATP-requiring processes that take up, or engulf, extracellular substances by enclosing them in a small membranous vesicle. Once the vesicle is formed, it detaches from the plasma membrane and moves into the cytoplasm (then it will either fuse with a lysosome and be digested or leave by exocytosis)
endocytosis
endocytosis is also called this; a term that means “cell-eating”
phagocytosis
form of endocytosis; the cel “gulps” droplets of extracellular fluid; cell-drinking. The plasma membrane indents to form a tiny pit, and then its edges fuse around the droplet of extracellular fluid contains dissolved proteins or fats; routine activity for the cell
pinocytosis
how is phagocytosis a protective mechanism?
certain white blood cells and other “professional” phagocytes of the body act as scavenger cells that police and protect the body by ingesting bacteria and other foreign debris.
main cellular mechanism for taking up specific target molecules. receptor proteins on the plasma membrane bind only with certain substances. Both the receptors and high concentrations of the attached target molecules are internalized in a vesicle and are dealt with.
receptor-mediated endocytosis
a homogenous mixture of two or more components
solution
