| A | B |
|---|
| multicellular organism | an organism that contains more than one cell |
| receptor proteins | proteins found embedded in the cell membrane that send signals to the inside of the cell |
| voltage-sensitive channel | protein channels that are responsive to electrical currents, example nerve cells |
| cell surface markers | proteins embedded in the cell membrane that identify the cell |
| diffusion | movement of substance from a region of high concentration to a region of lower concentration, uses kinetic energy of the molecules |
| osmosis | diffusion of water |
| selective transport | movement of specific molecules by means of protein channels and pumps |
| facilitated diffusion | form of selective transport that can only move molecules from high to low concentration |
| active transport | movement of molecules that require ATP (cell's energy), molecules can be concentrated against the gradient |
| sodium-potassium pump | channels which move sodium ions out of the cell and potassium ions into the cell |
| proton pump | protein pumps that move hydrogen protons out of the cell to balance pH (acidity) or help generate ATP |
| endocytosis | process of the cell engulfing large particles to bring them inside the cell |
| exocytosis | wastes or secretions expelled from the cell using small sacs |
| metabolism | chemical reactions that occur in a cell |
| activation energy | energy required to start a reaction |
| enzyme | protein that controls chemical reactions in a cell |
| catalyst | compound that lowers the activation energy for a chemical reaction, example - enzymes |
| substrate | molecule that an enzyme changes |
| active site | region on an enzyme that the substrate binds |
| ATP | energy molecule of the cell that is used for metabolism |
| photosynthesis | process of capturing the sun's energy and using it to make sugar |
| cellular respiration | process of taking apart molecules and transferring the energy to ATP |
| chlorophyll | a green pigment that captures the sun's energy |
| glycolysis | the first step in cellular respiration |
| oxidative respiration | process that requires oxygen to finish breaking a glucose molecule down and transferring the energy to ATP |
| pyruvic acid | the end product of glycoysis |
| fermentation | process of converting pyruvic acid to alcohol and carbon dioxide |
| feedback inhibition | slowing or stopping a reaction to control metabolism |
