Module Two Flashcards
What are metabolism (2 examples) and bioenergetics?
Metabolism: Total chemical reactions in a cell, divided into:
Catabolism: Breaks molecules, releasing energy.
Anabolism: Builds molecules, using energy.
Bioenergetics: How cells manage energy flow, converting high-energy molecules (e.g., glucose) into ATP for cellular work.
What are the function and regulation mechanisms of enzymes?
Function: Enzymes are proteins that speed up reactions by lowering activation energy.
Regulation:
Inhibitors: Molecules that block activity (e.g., competitive or non-competitive inhibitors).
Feedback Inhibition: The reaction product inhibits the enzyme to prevent overproduction.
Why is ATP important to cells?
ATP (adenosine triphosphate) is the main energy currency. It stores energy in phosphate bonds, releasing it when the bond between the last two phosphates is broken. This powers processes like muscle contraction and molecule transport.
What are oxidation and reduction reactions, and why are they important?
Oxidation: Loss of electrons.
Reduction: Gain of electrons.
These reactions transfer energy. In respiration, electrons from glucose are passed to oxygen, releasing energy for ATP production.
What are electron carriers, and what role do they play in respiration?
Electron carriers like NAD⁺ and FAD transport high-energy electrons during respiration. They become NADH and FADH₂, delivering electrons to the electron transport chain, driving ATP production.
What is glycolysis, and what happens during this process?
Glycolysis occurs in the cytoplasm, breaking glucose (6 carbons) into two pyruvate molecules (3 carbons each).
Produces:
2 ATP molecules.
2 NADH molecules.
No oxygen required.
Describe the steps and products of pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation.
Pyruvate Oxidation:
Location: Mitochondria.
Pyruvate → Acetyl-CoA + CO₂ + NADH.
Citric Acid Cycle:
Acetyl-CoA enters the cycle.
Produces: CO₂, ATP, NADH, and FADH₂.
Oxidative Phosphorylation:
Electron Transport Chain: Electrons from NADH/FADH₂ move through proteins in the mitochondrial membrane.
Chemiosmosis: Proton gradient drives ATP synthase, producing most cellular ATP.
How is cellular respiration regulated?
Feedback inhibition controls key enzymes.
Phosphofructokinase regulates glycolysis:
High ATP slows respiration.
Low ATP accelerates it.
What are the differences between aerobic respiration, anaerobic respiration, and fermentation?
Aerobic Respiration:
Requires oxygen.
Produces 36-38 ATP per glucose.
Anaerobic Respiration:
No oxygen; uses alternative electron acceptors (e.g., nitrate or sulfate).
Produces less ATP than aerobic respiration.
Fermentation:
No oxygen; converts pyruvate to lactic acid (animals) or ethanol + CO₂ (yeast).
Produces only 2 ATP per glucose.
