Question | Answer |
What happens to a freshwater organism when it is transfered to sea water? | it's cells will shrink; crenate |
What factors influence the rate of diffusion through a selectively permeable membrane? | size of the molecules, temperature of the environment,concentration of the solutes |
Diffusion of nonpolar molecules are not affected by __________________. | charge |
Type of diffusion that requires energy of ATP. | active transport |
Type of diffusion that does not require the energy of ATP. | passive transport |
Types of active transport. | Na-K pump, endocytosis, exocytosis |
Movement of molecules from an area of low concentration to an area of high concentration would require ___________ and is therefore _________________. | ATP; active transport |
Molecules moving down the concentration gradient from high concentration to low concentration does not require ____________ and is therefore _______________. | ATP; passive transport |
An environment that has a higher solute concentration and a lower water concentration than the cell | hypertonic environment |
An environment with a hight water concentrationa and a lower solute concentration than the cell. | hypotonic environment |
An environment that has the same concentration of solutes and the same concentration of water as the cell. | isotonic environment |
What happens to a plant cell placed in a hypertonic environment? | contents shrink; plasmolysis |
What happens to an animal cell placed in a hypertonic environment? | it will shrink; crenate |
What happens to a plant cell placed in a hypotonic environment? | it will swell; turgid, stiff (not burst because of cell wall) |
What happens to an animal cell placed in a hypotonic environment? | it will swell and burst |
Passive transport that requires the use of a transport protein to transport the molecule across the membrane. | facilitated diffusion |
The gradual change in solute concentration high to low concentration. | concentration gradient |
The movement of molecules against the concentration gradient would be _____________. | active transport |
The gradual spreading of molecules from an area of high concentration to an area of low concentration. | diffusion |
The diffusion of water molecules only. | osmosis |
Sodium-potassium pump is an example of ______. | active transport |
The engulfing of molecules too large to fit through the integral proteins. Why can't plant cells do this? | phagocytosis; cell wall is to rigid |
who proposed the "Fluid Mosaic Model" for the structure of cell membranes? | Singer and Nicolson |
the fluid mosaic model of cell membranes proposes what structure of membranes | a phospholipid bilayer with embedded proteins |
animal cell membranes have what types of molecules as structural components? | phospholipids, proteins, and cholesterol |
what property does cholesterol add to animal cells | allows the membrane to be fluid like even at colder temperatures |
a molecule that is both hydrophobic and hydrophilic | amphipathic |
how can a polar compound like proteins be embedded in a nonpolar membrane | it must be amphipathic with both polar and nonpolar radicals in its tertiary structure |
how can fatty acids in the phospholipid help keep the membranes more fluid than solid? | double bond kinks spread the molecules out and keep them from packing together tightly; less dense |
proteins that span the width of the membrane | integral proteins |
proteins limited to the outer or inner surface of the plasma membrane | peripheral proteins |
molecules that pass through a membrane easily | small and hydrophobic |
molecules that pass through a membrane the fastest | gases; O2, CO2, etc. |
water diffuses through proteins called | aquaporin |
what is the voltage across a membrane called? | membrane potential |
types of passive transport | diffusion, osmosis, facilitated diffusion |
carrier molecules of the membrane used in active transport | proteins |
what happens to a cell placed in sea water | it shrivels (crenation) because sea water is hypertonic |
plant cells placed in fresh water | will become turgid from internal pressure caused by the gain of water |
a solution has of 5% salt concentration is separated from a solution of 15% salt concentration by a membrane that is permeable to salt but not to salt......what will happen | 5% side is hypotonic and water will move from the 5% side to the 15% side |