1. ENZYMES Energy and Chemical Reactions

2. Energy for Life Processes Energy – the ability to move or change matter. Light energy, heat energy, chemical energy, mechanical energy, and electrical energy. Energy – the ability to move or change matter. Light energy, heat energy, chemical energy, mechanical energy, and electrical energy. Energy can be converted from one form to another. If you cook an egg in a hot pan, heat caused the egg to change color and solidify. The energy transferred to the egg by heat rearranges the atoms and molecules in the egg, causing it to go from a liquid to a solid. Energy can be converted from one form to another. If you cook an egg in a hot pan, heat caused the egg to change color and solidify. The energy transferred to the egg by heat rearranges the atoms and molecules in the egg, causing it to go from a liquid to a solid.

3. Energy can be stored or released by chemical reactions. A chemical reaction is a process during which chemical bonds between atoms are broken and new ones are formed, producing one or more different substances. Energy can be stored or released by chemical reactions. A chemical reaction is a process during which chemical bonds between atoms are broken and new ones are formed, producing one or more different substances. Reactants: the starting material for chemical reactions. Reactants: the starting material for chemical reactions. Products: the newly formed substances from a chemical reaction Products: the newly formed substances from a chemical reaction

5. Energy in Chemical Reactions In chemical reactions, energy is released and absorbed when chemical bonds are broken and new ones are formed. In chemical reactions, energy is released and absorbed when chemical bonds are broken and new ones are formed. Example: energy is released from water as heat, and the water freezes. Example: energy is released from water as heat, and the water freezes. Example: ice absorbs energy as heat from the environment, and the ice melts. Example: ice absorbs energy as heat from the environment, and the ice melts.

6. Activation Energy Activation Energy – the energy needed to start a chemical reaction. Example: It takes a few seconds for a car to actually start. Activation Energy – the energy needed to start a chemical reaction. Example: It takes a few seconds for a car to actually start.

7. Enzymes Enzymes – substances that increase the speed of chemical reactions. Most enzymes are proteins that work best at a specified pH. Another word for enzymes is catalyst. Enzymes – substances that increase the speed of chemical reactions. Most enzymes are proteins that work best at a specified pH. Another word for enzymes is catalyst. Enzymes help organisms maintain homeostasis. Without them, chemical reactions would not occur quickly enough to sustain life. Enzymes help organisms maintain homeostasis. Without them, chemical reactions would not occur quickly enough to sustain life.

8. Enzyme Specificity Substrate – a substance on which an enzyme acts during a chemical reaction. Enzymes act only on specific substrates. Substrate – a substance on which an enzyme acts during a chemical reaction. Enzymes act only on specific substrates. Example: the enzyme catalase in our body breaks down the poisonous substance hydrogen peroxide.. Example: the enzyme catalase in our body breaks down the poisonous substance hydrogen peroxide.. An enzyme’s shape determines its activity. An enzyme is usually a large protein with one or more deep folds on its surface. These folds form pockets called active sites. An enzyme’s substrate will fit into the active site. Only the specific substrate will fit into the enzyme’s active site. An enzyme’s shape determines its activity. An enzyme is usually a large protein with one or more deep folds on its surface. These folds form pockets called active sites. An enzyme’s substrate will fit into the active site. Only the specific substrate will fit into the enzyme’s active site.

11. How an Enzyme works: Step 1: When an enzyme first attaches to a substrate during a chemical reaction, the enzyme’s shape changes slightly so that the substrate fits more tightly in the enzyme’s active site.

12. Step 2: At an active site, an enzyme and a substrate interact in a way that reduces the activation energy of the reaction, making the substrate more likely to react. Step 3: The reaction is complete when products have formed. The enzyme is now free to catalyze further reactions. Notice, the enzyme never changes, and is never harmed.

13. Inhibitors Inhibitors – an inhibitor is a substance that fits into the active site of an enzyme to slow the reaction down. Inhibitors – an inhibitor is a substance that fits into the active site of an enzyme to slow the reaction down.