AP Biology Flashcards: Cellular Energy

What this deck covers

This deck focuses on Cellular Energy, giving you a quick way to review the definitions, rules, and examples that matter most for AP Biology.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: Identify the process that generates ATP using a proton gradient.

Answer: Chemiosmosis. Uses proton gradient to drive ATP formation.

Flashcard 2: Identify the wavelengths of light most effectively absorbed by chlorophyll.

Answer: Blue and red wavelengths. Green light is reflected, not absorbed.

Flashcard 3: Which molecule provides electrons for the light-dependent reactions?

Answer: Water (H$_2$O). Split by light to provide electrons and protons.

Flashcard 4: Which two processes are linked by the electron transport chain?

Answer: Glycolysis/Krebs cycle and oxidative phosphorylation. Electrons from metabolism power ATP synthesis.

Flashcard 5: What is photorespiration?

Answer: Process where Rubisco adds O$_2$ instead of CO$_2$ to RuBP. Wasteful process that reduces photosynthetic efficiency.

Flashcard 6: Which organelle is primarily involved in energy production?

Answer: Mitochondrion. Known as the powerhouse of the cell.

Flashcard 7: Which molecule acts as the main electron carrier in photosynthesis?

Answer: NADP+. Similar to NADH but used in photosynthetic reactions.

Flashcard 8: Which molecule is regenerated at the end of the Calvin cycle?

Answer: RuBP (Ribulose bisphosphate). Five-carbon sugar that accepts $CO_2$ in carbon fixation.

Flashcard 9: Which type of plant minimizes photorespiration by fixing CO$_2$ into four-carbon compounds?

Answer: C4 plants. Spatial separation prevents photorespiration in hot climates.

Flashcard 10: Which photosystem is involved in the splitting of water?

Answer: Photosystem II. First photosystem that oxidizes water molecules.

Flashcard 11: Which molecule acts as the main electron carrier in photosynthesis?

Answer: NADP+. Similar to NADH but used in photosynthetic reactions.

Flashcard 12: What is substrate-level phosphorylation?

Answer: Direct transfer of a phosphate group to ADP to form ATP. ATP formed directly from substrate without electron transport.

Flashcard 13: How many ATP are produced from one molecule of glucose in cellular respiration?

Answer: Approximately 30-32 ATP. Complete oxidation yields maximum ATP from glucose.

Flashcard 14: Which enzyme synthesizes ATP in the electron transport chain?

Answer: ATP synthase. Uses proton gradient to drive ATP production.

Flashcard 15: How many ATP are produced from one molecule of glucose in cellular respiration?

Answer: Approximately 30-32 ATP. Complete oxidation yields maximum ATP from glucose.

Flashcard 16: State the formula for cellular respiration.

Answer: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{Energy (ATP)}$. Glucose and oxygen react to produce carbon dioxide, water, and ATP.

Flashcard 17: What is the role of Rubisco in the Calvin cycle?

Answer: Catalyzes the fixation of CO$_2$. Key enzyme that combines $CO_2$ with RuBP.

Flashcard 18: Identify the wavelengths of light most effectively absorbed by chlorophyll.

Answer: Blue and red wavelengths. Green light is reflected, not absorbed.

Flashcard 19: What is the main adaptation of CAM plants?

Answer: Stomata open at night to minimize water loss. Temporal separation conserves water in dry environments.

Flashcard 20: What molecule is glucose converted into during glycolysis?

Answer: Pyruvate. Three-carbon molecule produced when glucose splits in half.

Flashcard 21: State the main product of alcohol fermentation.

Answer: Ethanol. Produced by yeast during anaerobic fermentation.

Flashcard 22: State the equation for photosynthesis.

Answer: $6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2$. Overall equation showing reactants and products of photosynthesis.

Flashcard 23: Which two processes are linked by the electron transport chain?

Answer: Glycolysis/Krebs cycle and oxidative phosphorylation. Electrons from metabolism power ATP synthesis.

Flashcard 24: What is the purpose of fermentation in cells?

Answer: Regenerate NAD+ for glycolysis. Allows glycolysis to continue when oxygen is unavailable.

Flashcard 25: Which type of plant minimizes photorespiration by fixing CO$_2$ into four-carbon compounds?

Answer: C4 plants. Spatial separation prevents photorespiration in hot climates.

Flashcard 26: Which molecule is regenerated at the end of the Calvin cycle?

Answer: RuBP (Ribulose bisphosphate). Five-carbon sugar that accepts $CO_2$ in carbon fixation.

Flashcard 27: Where does the Calvin cycle take place?

Answer: Stroma of the chloroplast. Fluid-filled space surrounding thylakoid membranes.

Flashcard 28: Identify the final electron acceptor in the electron transport chain.

Answer: Oxygen. Accepts electrons at the end of the transport chain.

Flashcard 29: In which part of the chloroplast do the light-dependent reactions occur?

Answer: Thylakoid membranes. Contains chlorophyll and photosystems for light capture.

Flashcard 30: Identify the location of the Krebs cycle in the cell.

Answer: Mitochondrial matrix. Innermost compartment of mitochondria where citric acid cycle occurs.

Flashcard 31: Identify the process that generates ATP using a proton gradient.

Answer: Chemiosmosis. Uses proton gradient to drive ATP formation.

Flashcard 32: What is chemiosmosis?

Answer: Movement of ions across a semipermeable membrane, down their electrochemical gradient. Drives ATP synthesis using proton concentration differences.

Flashcard 33: Which phase of cellular respiration occurs in the cytoplasm?

Answer: Glycolysis. First stage breaks down glucose without oxygen.

Flashcard 34: What is the net gain of ATP from glycolysis?

Answer: 2 ATP. Four ATP produced minus two ATP invested equals net gain.

Flashcard 35: What is the role of NADH in cellular respiration?

Answer: Electron carrier. Transfers high-energy electrons to the electron transport chain.

Flashcard 36: Which process produces the most ATP: glycolysis, Krebs cycle, or oxidative phosphorylation?

Answer: Oxidative phosphorylation. Generates about 28-30 ATP molecules through electron transport.

Flashcard 37: What is the net gain of ATP from glycolysis?

Answer: 2 ATP. Four ATP produced minus two ATP invested equals net gain.

Flashcard 38: What is the main adaptation of CAM plants?

Answer: Stomata open at night to minimize water loss. Temporal separation conserves water in dry environments.

Flashcard 39: What molecule is glucose converted into during glycolysis?

Answer: Pyruvate. Three-carbon molecule produced when glucose splits in half.

Flashcard 40: What is the primary function of the light-dependent reactions?

Answer: To produce ATP and NADPH. Energy carriers needed for the Calvin cycle.

Flashcard 41: Which photosystem is involved in the splitting of water?

Answer: Photosystem II. First photosystem that oxidizes water molecules.

Flashcard 42: Identify the location of the Krebs cycle in the cell.

Answer: Mitochondrial matrix. Innermost compartment of mitochondria where citric acid cycle occurs.

Flashcard 43: What is photorespiration?

Answer: Process where Rubisco adds O$_2$ instead of CO$_2$ to RuBP. Wasteful process that reduces photosynthetic efficiency.

Flashcard 44: Identify the final electron acceptor in the electron transport chain.

Answer: Oxygen. Accepts electrons at the end of the transport chain.

Flashcard 45: What is the function of the electron transport chain?

Answer: Transfer electrons to create a proton gradient for ATP synthesis. Creates proton gradient that powers ATP synthase.

Flashcard 46: State the equation for photosynthesis.

Answer: $6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2$. Overall equation showing reactants and products of photosynthesis.

Flashcard 47: Where does the Calvin cycle take place?

Answer: Stroma of the chloroplast. Fluid-filled space surrounding thylakoid membranes.

Flashcard 48: What is the purpose of fermentation in cells?

Answer: Regenerate NAD+ for glycolysis. Allows glycolysis to continue when oxygen is unavailable.

Flashcard 49: What is the primary function of the light-dependent reactions?

Answer: To produce ATP and NADPH. Energy carriers needed for the Calvin cycle.

Flashcard 50: State the formula for cellular respiration.

Answer: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{Energy (ATP)}$. Glucose and oxygen react to produce carbon dioxide, water, and ATP.

Flashcard 51: What are the end products of the light-dependent reactions?

Answer: ATP, NADPH, and O$_2$. Light reactions produce energy carriers and release oxygen.

Flashcard 52: What are the end products of the light-dependent reactions?

Answer: ATP, NADPH, and O$_2$. Light reactions produce energy carriers and release oxygen.

Flashcard 53: Which molecule provides electrons for the light-dependent reactions?

Answer: Water (H$_2$O). Split by light to provide electrons and protons.

Flashcard 54: What is the primary pigment involved in photosynthesis?

Answer: Chlorophyll. Green pigment that absorbs light energy.

Flashcard 55: Which organelle is primarily involved in energy production?

Answer: Mitochondrion. Known as the powerhouse of the cell.

Flashcard 56: Which enzyme synthesizes ATP in the electron transport chain?

Answer: ATP synthase. Uses proton gradient to drive ATP production.

Flashcard 57: What is the initial reactant in the Krebs cycle?

Answer: Acetyl-CoA. Two-carbon unit that enters the citric acid cycle.

Flashcard 58: What is the main purpose of the Calvin cycle?

Answer: To convert CO$_2$ into glucose. Light-independent reactions that fix carbon dioxide.

Flashcard 59: During which process is carbon dioxide released in cellular respiration?

Answer: Krebs cycle. Carbon atoms are removed as $CO_2$ during this cycle.

Flashcard 60: What is the role of Rubisco in the Calvin cycle?

Answer: Catalyzes the fixation of CO$_2$. Key enzyme that combines $CO_2$ with RuBP.

Flashcard 61: Identify the process that converts light energy into chemical energy.

Answer: Photosynthesis. Plants capture sunlight to make glucose.

Flashcard 62: What is the role of coenzyme A in cellular respiration?

Answer: Transfers acetyl group to Krebs cycle. Carries acetyl groups from pyruvate to Krebs cycle.

Flashcard 63: In which part of the chloroplast do the light-dependent reactions occur?

Answer: Thylakoid membranes. Contains chlorophyll and photosystems for light capture.

Flashcard 64: What is the main purpose of the Calvin cycle?

Answer: To convert CO$_2$ into glucose. Light-independent reactions that fix carbon dioxide.

Flashcard 65: Which process produces the most ATP: glycolysis, Krebs cycle, or oxidative phosphorylation?

Answer: Oxidative phosphorylation. Generates about 28-30 ATP molecules through electron transport.

Flashcard 66: What is the function of the electron transport chain?

Answer: Transfer electrons to create a proton gradient for ATP synthesis. Creates proton gradient that powers ATP synthase.

Flashcard 67: Which type of fermentation occurs in muscle cells?

Answer: Lactic acid fermentation. Occurs during intense exercise when oxygen is limited.

Flashcard 68: Which phase of cellular respiration occurs in the cytoplasm?

Answer: Glycolysis. First stage breaks down glucose without oxygen.

Flashcard 69: What is the role of NADH in cellular respiration?

Answer: Electron carrier. Transfers high-energy electrons to the electron transport chain.

Flashcard 70: What is the main energy currency of the cell?

Answer: ATP (Adenosine Triphosphate). Stores and releases energy through phosphate bonds.

Flashcard 71: During which process is carbon dioxide released in cellular respiration?

Answer: Krebs cycle. Carbon atoms are removed as $CO_2$ during this cycle.

Flashcard 72: Which type of fermentation occurs in muscle cells?

Answer: Lactic acid fermentation. Occurs during intense exercise when oxygen is limited.

Flashcard 73: What is the initial reactant in the Krebs cycle?

Answer: Acetyl-CoA. Two-carbon unit that enters the citric acid cycle.

Flashcard 74: State the main product of alcohol fermentation.

Answer: Ethanol. Produced by yeast during anaerobic fermentation.

Flashcard 75: What is the main energy currency of the cell?

Answer: ATP (Adenosine Triphosphate). Stores and releases energy through phosphate bonds.

Flashcard 76: Identify the process that converts light energy into chemical energy.

Answer: Photosynthesis. Plants capture sunlight to make glucose.