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BIOD 101 – MODULE 3 PRACTICE EXAM
Portage Learning – Foundations of Biology I (2025 Edition)
Metabolic Pathways, Cellular Respiration, Glycolysis, CAC, ETC, Fermentation
Practice Set Overview
- Total Questions: 100
- Includes: o True/False o Fill-in-the-Blank o Short Answer o Definitions
Topics Covered
- • Chemical reactions: Redox, Hydrolysis, Dehydration, CondensationMetabolic classifications: Catabolism vs. Anabolism
- Glycolysis phases: Investment and Payoff
- Energy carriers: ATP, NADH, FADH₂
- Citric Acid Cycle (Krebs Cycle): Steps and intermediates
- • Electron Transport Chain (ETC): Complexes IATP Synthase and Oxidative Phosphorylation–IV, Ubiquinone, Cytochrome C
- Anaerobic Respiration and Fermentation (Alcohol and Lactic Acid)
- Enzymes: Hexokinase, Phosphofructokinase, Aldolase, Pyruvate kinase
- Energy yield calculations: Aerobic vs. Anaerobic pathways
Who Should Use This
- • Portage Learning students preparing forBiology students seeking to master cellular respiration and energy pathways Module 3 exams
- Those reviewing biochemical reactions and ATP production mechanisms
Compiled: 2025 Course: BIOD 101 – Foundations of Biology I Institution: Portage Learning Exam Style: Verified Q&A structured like real Portage module assessments
PORTAGE LEARNING BIOD 101 – MODULE 3
- True or False Statement: ATP synthase is directly powered by the transfer of electrons.
Answer: False ATP synthase is powered by the proton gradient across the inner mitochondrial membrane.
- Fill in the Blank Question: In glycolysis, the molecule glucose is broken down into two molecules of ________.
Answer: Pyruvate
- Short Answer Question: What is the net ATP yield from glycolysis per glucose molecule?
Answer: 2 ATP (4 ATP produced - 2 ATP used)
- Definition Term: Oxidative Phosphorylation Definition: The process of ATP formation driven by the transfer of electrons through the electron transport chain to oxygen.
- True or False Statement: FADH₂ donates electrons to Complex I in the electron transport chain.
Answer: False FADH₂ donates electrons to Complex II.
Question: What role does NAD⁺ play in cellular respiration?
Answer: NAD⁺ acts as an electron carrier, becoming reduced to NADH during glycolysis and the Krebs cycle.
- Definition Term: Anaerobic Respiration Definition: A form of respiration using electron acceptors other than oxygen.
- True or False Statement: The energy investment phase of glycolysis consumes 2 ATP molecules.
Answer: True
- Fill in the Blank Question: Each NADH molecule contributes enough energy to produce approximately ________ ATP molecules.
Answer: 2.5 ATP
- Short Answer Question: What is the main function of the electron transport chain?
Answer: To pump protons across the inner mitochondrial membrane and generate a proton gradient for ATP synthesis.
- Definition Term: Chemiosmosis Definition: The movement of protons down their gradient across a membrane to generate ATP via ATP synthase.
- True or False Statement: Carbon dioxide is produced during glycolysis.
Answer: False CO₂ is released during the citric acid cycle, not glycolysis.
- Fill in the Blank Question: The enzyme that catalyzes the final step of glycolysis is ________.
Answer: Pyruvate kinase
- Short Answer Question: In which part of cellular respiration is FAD reduced to FADH₂?
Answer: In the citric acid cycle (Krebs cycle)
- Definition Term: Lactic Acid Fermentation Definition: A form of anaerobic respiration where pyruvate is reduced to lactic acid to regenerate NAD⁺.
- True or False Statement: Oxygen is required for glycolysis to occur.
Answer: False Glycolysis is an anaerobic process.
- Fill in the Blank
Answer: 30 – 32 ATP
- Definition Term: Alcoholic Fermentation Definition: Anaerobic pathway converting pyruvate into ethanol and CO₂ to regenerate NAD⁺.
- True or False Statement: The ETC pumps protons into the mitochondrial matrix.
Answer: False Protons are pumped into the intermembrane space.
- Fill in the Blank Question: The name of the enzyme complex responsible for producing ATP from ADP and Pi is ________.
Answer: ATP synthase
- True or False Statement: Acetyl-CoA is produced from pyruvate through a decarboxylation reaction.
Answer: True Pyruvate loses a carbon as CO₂ before becoming acetyl-CoA.
- Fill in the Blank
Question: During glycolysis, glucose is phosphorylated by ATP to become ________.
Answer: Glucose-6-phosphate
- Short Answer Question: What is the function of ubiquinone (coenzyme Q) in the electron transport chain?
Answer: It transfers electrons between Complex I or II to Complex III.
- Definition Term: Citric Acid Cycle (Krebs Cycle) Definition: A series of enzyme-catalyzed reactions in the mitochondrial matrix that oxidize acetyl-CoA, producing NADH, FADH₂, and CO₂.
- True or False Statement: The main purpose of fermentation is to generate additional ATP.
Answer: False Its primary purpose is to regenerate NAD⁺ for glycolysis.
- Fill in the Blank Question: In the citric acid cycle, ________ is regenerated at the end to continue the cycle.
Answer: Oxaloacetate
- Short Answer Question: Which molecules from glycolysis carry electrons to the electron transport chain?
Answer: NADH
Statement: Pyruvate can enter the mitochondrion directly without transport proteins.
Answer: False Pyruvate must be actively transported into the mitochondrial matrix.
- Fill in the Blank Question: ________ is the molecule that links glycolysis to the citric acid cycle.
Answer: Acetyl-CoA
- Short Answer Question: What step of cellular respiration produces the most ATP?
Answer: Oxidative phosphorylation (electron transport + chemiosmosis)
- Definition Term: NADH Definition: A high-energy electron carrier used in cellular respiration that donates electrons to the ETC.
- True or False Statement: Complex IV of the ETC transfers electrons to oxygen.
Answer: True Oxygen is the terminal electron acceptor, forming water.
- Fill in the Blank
Question: In alcohol fermentation, pyruvate is first converted to ________, releasing CO₂.
Answer: Acetaldehyde
- Short Answer Question: What enzyme catalyzes the rate-limiting step in glycolysis?
Answer: Phosphofructokinase
- Definition Term: Fermentation Definition: An anaerobic process that allows glycolysis to continue by regenerating NAD⁺.
- True or False Statement: ATP can be produced both aerobically and anaerobically.
Answer: True
- Fill in the Blank Question: The enzyme that breaks the 6-carbon sugar into two 3-carbon sugars in glycolysis is ________.
Answer: Aldolase
- Short Answer
- True or False Statement: FADH₂ produces more ATP than NADH.
Answer: False FADH₂ enters the ETC later and contributes less to the proton gradient.
- Fill in the Blank Question: The complete oxidation of one glucose molecule can theoretically yield ________ ATP.
Answer: 30 – 32 ATP
