| Term | Definition |
|---|
| concentration | The number of molecules (solute) per unit of solvent. (the solvent in cells is water) |
| equilibrium | Is reached when the rate of movement in one direction is the same as the rate of movement in the other direction. |
| homeostasis | The cells expends energy to maintain a steady inside environment state. |
| phospholipid bilayer | Impose a barrier between the inside and the outside of the cell. Hydrophillic "heads" and hydrophobic "tails". The cell membrane. |
| hydrophilic | Molecules that dissolve in water. (polar) |
| hydrophobic | Will not dissolve in water. (non-polar) |
| glycoproteins | Receptor and recognition proteins. They have an oligosaccharide molecule attached to them. |
| transport proteins | Aka "channel proteins". These fold in such a way as to create a hole (membrane pores) down their center. Allow water soluble substances to cross the lipid bilayer. |
| receptor proteins | Bind extracellular substances which then cause changes in the cell. (exp. neurotransmitter receptors) |
| recognition proteins | Also gycopoteins. Function as ID tags. Identify cell type within an organism. Used to identify one organism from another. |
| adhesion proteins | Some may be glycoproteins. Locate and stick to others of the same type in multicellular organisms. |
| gradient | When two locations differ in the amount of something, then there is a _____ between them. |
| diffusion | Cell expends no energy; passive transport; The process in which there is movement of a substance from an area of high concentration of that substance to an area of lower concentration |
| active transport | Like doors; can be shut. Substances can only be moved through them by the expenditure of energy in the form of ATP. |
| passive transport | Like open windows. (aka "pores") Can move in both directions. Net movement depends only on the concentration gradient. |
| facilitated diffusion | Solutes are "helped" to move down their concentration gradients by the presence of channels. |
| membrane pump | Active Transport Proteins |
| solvent | In cells: water; The substance in which a solute is dissolved. |
| solute | The dissolved substance in a solution. |
| osmosis | the diffusion of water across a semi-permeable membrane |
| hypertonic | A solution that is more concentrated than another. (Little water) |
| hypotonic | A solution is less concentrated. (Lots of water) |
| isotonic | The solutions are equal in concentration |
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