BIOL 1201 WITH ACCURATE QUESTIONS AND DETAILED SOLUTIONS|SURE TO PASS|

1. How can you tell if a reaction is spontaneous using ΔG (free energy)? ANSWER A negative ΔG indicates a spontaneous (exergonic) reaction; a positive ΔG indicates a non spontaneous (endergonic) reaction. 2. How do enzymes speed up chemical reactions? ANSWER By lowering the activation energy barrier without being consumed. 3. What stays the same and what changes when enzymes are used in a reaction? ANSWER Free energy (ΔG) stays the same, activation energy is lowered. 4. What are some factors that affect enzyme catalytic ability? ANSWER Temperature, pH, substrate concentration, cofactors, and inhibitors. 5. Compare competitive and noncompetitive inhibition. ANSWER Competitive inhibitors bind to the active site; noncompetitive inhibitors bind elsewhere and change enzyme shape. 6. How many ATP are produced from cellular respiration ANSWER 32 ATP 7. What are the four main stages of cellular respiration? ANSWER Glycolysis, Pyruvate Oxidation, Citric Acid Cycle, and Oxidative Phosphorylation. 8. What are the products of glycolysis per glucose molecule? ANSWER 2 pyruvate, 2 net ATP, and 2 NADH. 9. During pyruvate oxidation, what does each pyruvate become? ANSWER Each pyruvate is converted into acetyl-CoA, producing CO₂ and NADH. 10. What is the purpose of the electron transport chain (ETC)? ANSWER To transfer electrons from NADH and FADH₂ through protein complexes and pump protons to create a gradient. 11. What is the final electron acceptor in the ETC? ANSWER Oxygen 12. What are the two main parts of a photosystem? ANSWER Light-harvesting complex and reaction center complex. 13. What is the function of the primary electron acceptor? ANSWER Captures excited electrons from chlorophyll a. 14. Which photosystem is P680, and what does it do best? ANSWER Photosystem II, absorbs light at 680 nm, comes first. 15. Which photosystem is P700, and when does it occur? ANSWER Photosystem I, absorbs light at 700 nm, comes second. 16. What are the two types of electron flow? ANSWER Linear and cyclic. 17. What does linear electron flow produce? ANSWER ATP and NADPH. 18. What does cyclic electron flow produce? ANSWER ATP only. 19. Which photosystems are used in linear electron flow? ANSWER Photosystem I and II. 20. How is the proton gradient location different in mitochondria vs chloroplasts? ANSWER Mitochondria: pumped into intermembrane space. Chloroplasts: pumped into thylakoid space. 21. Where does the Calvin cycle occur? ANSWER In the stroma. 22. What molecule does the Calvin cycle produce? ANSWER G3P (glyceraldehyde-3-phosphate). 23. What enzyme catalyzes carbon fixation in the Calvin cycle? ANSWER Rubisco. 24. During the reduction phase, how many net G3P molecules are gained per 3 CO₂? ANSWER One G3P. 25. What type of plants perform photorespiration? ANSWER C3 plants. 26. What enzyme do C4 plants use to capture CO₂ efficiently? ANSWER PEP carboxylase 27. When do CAM plants open their stomata? ANSWER At night 28. What connects sister chromatids? ANSWER Cohesins at the centromere. 29. What are the two major parts of the cell cycle? ANSWER Interphase and the mitotic phase. 30. What are the three stages of interphase? ANSWER G1, S, G2. 31. What happens in G1 phase? ANSWER Cell growth and metabolism. 32. What happens in S phase? ANSWER DNA is synthesized (chromosomes duplicated). 33. What happens in G2 phase? ANSWER More growth and preparation for division. 34. What happens during prophase? ANSWER Chromatin condenses, mitotic spindle forms. 35. What happens during prometaphase? ANSWER Nuclear envelope breaks down, spindle attaches to kinetochores. 36. What happens during metaphase? ANSWER Chromosomes align at the metaphase plate. 37. What are the three main types of transport across the membrane? ANSWER Passive transport, active transport, and bulk transport (exocytosis + endocytosis). 38. What is the difference between saturated and unsaturated fatty acid tails in the membrane? ANSWER Saturated tails pack tightly and help maintain integrity at higher temperatures, while unsaturated tails (with double bonds) keep the membrane more fluid, especially in cold temperatures. 39. What role does cholesterol play in the cell membrane? ANSWER It helps maintain fluidity at low temperatures and restrains movement at high temperatures. 40. What is selective permeability? ANSWER The property of the plasma membrane that allows some substances to cross more easily than others. 41. How does facilitated diffusion differ from simple diffusion? ANSWER Facilitated diffusion uses transport proteins to move molecules down their concentration gradient; simple diffusion does not require proteins. 42. What is the function of aquaporins? ANSWER They are channel proteins specifically for water transport. 43. Define osmosis. ANSWER The diffusion of water across a selectively permeable membrane. 44. Which environment is ideal for plant cells: isotonic, hypertonic, or hypotonic? ANSWER Hypotonic, because water enters the cell and keeps it turgid. 45. What is the difference between channel proteins and carrier proteins? ANSWER Channel proteins form pores for molecules to pass through; carrier proteins change shape to move molecules across. 46. Active transport always requires what type of protein? ANSWER Carrier proteins. 47. What is an electrogenic pump? ANSWER A transport protein that generates voltage across a membrane by moving ions. 48. Name the three types of endocytosis ANSWER Phagocytosis ("cell eating"), pinocytosis ("cell drinking"), and receptor-mediated endocytosis. 49. What is feedback inhibition? ANSWER A form of negative regulation where the end product of a pathway inhibits an earlier enzyme to prevent overproduction. 50. In redox reactions, what does LEO says GER mean? ANSWER Lose Electrons = Oxidized, Gain Electrons = Reduced.