🧬 CHAPTER 9 FLASHCARDS: Energy & Enzymes
1⃣ Metabolism Basics
Q: What is metabolism?
A: All chemical reactions that occur in a cell.
Q: What are the two types of metabolism?
A: Catabolism (breaks down molecules → releases energy) and Anabolism (builds molecules → uses energy).
Q: Which type of metabolism releases energy?
A: Catabolism.
Q: Which type of metabolism builds molecules using energy?
A: Anabolism.
2⃣ Energy Concepts
Q: What are the two main forms of energy?
A: Kinetic (motion) and Potential (stored).
Q: What does the First Law of Thermodynamics state?
A: Energy cannot be created or destroyed — only changed from one form to another.
Q: What does the Second Law of Thermodynamics state?
A: Every energy transfer increases entropy (disorder); some energy is lost as heat.
Q: What does “exergonic reaction” mean?
A: A reaction that releases energy (spontaneous).
Q: What does “endergonic reaction” mean?
A: A reaction that requires energy (non-spontaneous).
Q: What molecule is the cell’s main source of energy?
A: Adenosine Triphosphate (ATP).
Q: How does ATP release energy?
A: By breaking the bond between the second and third phosphate group (ATP → ADP + P).
Q: What is oxidation?
A: The loss of electrons.
Q: What is reduction?
A: The gain of electrons.
💡 Mnemonic: OIL RIG = Oxidation Is Loss, Reduction Is Gain
Q: What is activation energy (Ea)?
A: The minimum energy needed to start a reaction.
3⃣ Enzymes & Their Functions
Q: What are enzymes?
A: Proteins that speed up chemical reactions by lowering activation energy.
Q: What is a substrate?
A: The molecule that binds to an enzyme’s active site.
Q: What is the active site?
A: The region on an enzyme where the substrate binds and the reaction occurs.
Q: What are products in an enzyme reaction?
A: The new molecules formed after the reaction takes place.
Q: What are optimal conditions for enzymes?
A: The temperature and pH where the enzyme works best without denaturing.
Q: What happens if the enzyme’s shape changes?
A: It denatures and can no longer bind to its substrate.
Q: What are enzyme inhibitors?
A: Molecules that slow down or stop enzyme activity.
Q: What is a competitive inhibitor?
A: It binds directly to the enzyme’s active site and blocks the substrate.
Q: What is a non-competitive inhibitor?
A: It binds somewhere else on the enzyme and changes its shape.