Final Review Study Guide Answer Key atom - smallest unit of matter composed of protons, neutrons, and electrons molecule - 2 or more atoms bonded together chemical reaction - when the bonds in a molecule are broken and the atoms rearranged to form new molecules. enzyme - protein molecule that allows chemical reactions to occur by lowering the activation energy needed. It bonds with a substrate and changes it into a product substrate - the molecule an enzyme works on product - ending molecules in a reaction active site - spot on the enzyme where the substrate bonds and where the reaction occurs denaturation- changing the shape of the active site of an enzyme so the substrate can no longer fit. The wrong temperature or pH level can cause this inhibitor - a molecule similar to the substrate that bonds to the active site of an enzyme so the substrate cannot activation energy - the amount of energy needed to start a reaction. Enzymes lower it. reactant - starting molecule in a reaction cellular respiration - breaking down glucose to get ATP -consists of glycolysis, Kreb's cycle, and electron transport chain -occurs in the mitochondria -uses oxygen and makes carbon dioxide happens in animals and plants photosynthesis -using light energy to make glucose consists of the light reaction and the Calvin cycle occurs in the chloroplast produces oxygen and used carbon dioxide happens only in plants organelles and functions lysosome - breaks down waste in the cell vacuole - stores water food and waste mitochondria - where cellular respiration happens chloroplast - only in plants - where photosynthesis happens nucleus - has DNA and sends directions for making proteins to the ribosome ribosome - starts the process of making a protein and sends the amino acid chain to the rough ER to be folded rough Endoplasmic reticulum - folds proteins into their correct 3D shape Golgi apparatus - packages, labels, and inspects molecules for transport smooth ER - detoxifies alcohol and chemical and makes or synthesizes lipids cytoskeleton - gives cell shape and helps organelles move cell membrane - controls the passage of substances in and out of cells cell wall - only in plants - additional protection and lets cell fill with water without bursting (turgor pressure) Passive Transport - does not use energy by the cell -simple diffusion - more to less, small molecules, between phospholipids -facilitated diffusion - more to less, larger molecules, through protein channel -osmosis - diffusion of water Active Transport - cell uses ATP for energy to do it -active transport - nore to less through protein channel - small molecules or medium endocytosis - into the cell - very large molecules or cells exocytosis - out of the cell - very large molecules phospholipid bilayer - phosphate heads are turned out toward water, lipid tails are turned in away from water hydrophobic - water fearing lipid tails hydrophilic - water loving phosphate heads cellular respiration glucose and 6 oxygen molecules are used to make 6 carbon dioxide molecules, six water molecules and 36 ATP (net) photosynthesis 6 carbon dioxide molecules and 5 water molecules are used to make 1 glucose molecules and 6 oxygen molecules independent variable - changed in an experiment to test its effect dependent variable - changes as a result of the independent variable constants - factors kept the same in an experiment to ensure that any effects on the DV are due to the IV control - the level of the independent variable that simulates normal conditions reason for multiple trials - to insure accuracy how to find average - add numbers and divide by how many there are -