U3 vocab bio

I. Metabolism & Enzymes

1. Metabolism – The sum of all chemical reactions in an organism.

2. Catabolic Pathways – Break down molecules to release energy (e.g., cellular respiration).

3. Anabolic Pathways – Build complex molecules using energy (e.g., photosynthesis).

4. Exergonic Reaction – Releases energy; spontaneous (e.g., cellular respiration).

5. Endergonic Reaction – Requires energy input; non-spontaneous (e.g., photosynthesis).

6. Enzyme – A protein that acts as a catalyst to speed up reactions.

7. Activation Energy – The initial energy needed to start a reaction.

8. Substrate – The reactant that an enzyme acts on.

9. Active Site – The part of an enzyme where the substrate binds.

10. Induced Fit – The enzyme changes shape to fit the substrate more tightly.

11. Cofactor – A non-protein molecule (e.g., metal ions) that assists enzyme function.

12. Coenzyme – An organic cofactor (e.g., vitamins) that helps enzymes.

13. Competitive Inhibitor – Blocks the active site, preventing substrate binding.

14. Non-Competitive Inhibitor – Binds elsewhere, changing the enzyme’s shape.

15. Allosteric Regulation – A molecule binds to an enzyme at a site other than the active site, regulating activity.

II. Cellular Respiration

16. Cellular Respiration – The process of converting glucose into ATP using oxygen.

17. Aerobic Respiration – Requires oxygen; produces more ATP.

18. Anaerobic Respiration – Does not require oxygen; produces less ATP.

19. ATP (Adenosine Triphosphate) – The energy currency of the cell.

20. ADP (Adenosine Diphosphate) – Formed when ATP loses a phosphate group.

21. Oxidation – Loss of electrons (LEO: Lose Electrons = Oxidation).

22. Reduction – Gain of electrons (GER: Gain Electrons = Reduction).

23. Glycolysis – The first step in cellular respiration; breaks glucose into pyruvate.

24. Pyruvate – The three-carbon molecule produced from glycolysis.

25. Pyruvate Oxidation – Pyruvate is converted into Acetyl-CoA before entering the Krebs cycle.

26. Acetyl-CoA – The molecule that enters the Krebs cycle.

27. Krebs Cycle (Citric Acid Cycle) – A cycle that generates NADH and FADH₂ by oxidizing Acetyl-CoA.

28. NADH & FADH₂ – Electron carriers that store energy for the electron transport chain.

29. Electron Transport Chain (ETC) – A series of proteins in the inner mitochondrial membrane that transfer electrons and produce ATP.

30. Oxidative Phosphorylation – ATP synthesis driven by the movement of electrons through the ETC.

31. Chemiosmosis – The movement of protons across a membrane to generate ATP.

32. ATP Synthase – An enzyme that uses the proton gradient to produce ATP.

33. Final Electron Acceptor – Oxygen (O₂) in aerobic respiration, forming water (H₂O).

34. Lactic Acid Fermentation – Anaerobic respiration in muscles that produces lactic acid.

35. Alcoholic Fermentation – Anaerobic process in yeast that produces ethanol and CO₂.

III. Photosynthesis

36. Photosynthesis – The process by which light energy is converted into chemical energy (glucose).

37. Autotrophs – Organisms that produce their own food (e.g., plants).

38. Chloroplast – The organelle where photosynthesis occurs.

39. Thylakoid – The membrane sacs inside chloroplasts where the light-dependent reactions occur.

40. Grana – Stacks of thylakoids.

41. Stroma – The fluid-filled space inside chloroplasts where the Calvin cycle occurs.

42. Light-Dependent Reactions – The first stage of photosynthesis that converts light energy into ATP and NADPH.

43. Photolysis – The splitting of water to produce oxygen, protons, and electrons.

44. Photosystem – Protein-pigment complexes in the thylakoid membrane that absorb light energy.

45. Photosystem II (PSII) – Captures light and starts the electron transport chain; splits water to release O₂.

46. Photosystem I (PSI) – Captures light and produces NADPH.

47. Electron Transport Chain (ETC) in Photosynthesis – Transfers electrons to produce ATP and NADPH.

48. NADPH – An electron carrier used in the Calvin cycle.

49. ATP Synthase in Photosynthesis – Uses a proton gradient to synthesize ATP.

50. Calvin Cycle (Light-Independent Reactions) – Uses ATP and NADPH to convert CO₂ into glucose.

51. Carbon Fixation – The incorporation of CO₂ into organic molecules by Rubisco.

52. Rubisco – The enzyme that catalyzes carbon fixation in the Calvin cycle.

53. G3P (Glyceraldehyde-3-Phosphate) – A product of the Calvin cycle that forms glucose.

IV. Additional Key Concepts

54. C3 Plants – Use only the Calvin cycle for carbon fixation (e.g., rice, wheat).

55. C4 Plants – Have an adaptation that minimizes photorespiration (e.g., corn, sugarcane).

56. CAM Plants – Store CO₂ at night to prevent water loss (e.g., cacti, succulents).

57. Photorespiration – A wasteful process where Rubisco binds oxygen instead of CO₂, reducing photosynthesis efficiency.

58. Energy Coupling – The use of an exergonic process (like ATP hydrolysis) to drive an endergonic process.

59. Feedback Inhibition – A regulatory mechanism where a product of a pathway inhibits an earlier step.

60. Proton Gradient – A difference in proton concentration across a membrane that drives ATP production.