Photosynthesis, Calvin Cycle & Cellular Respiration

• Study notes based on flashcard questions and answers are presented

Photosynthesis

• Reactants: Carbon dioxide (CO₂), water (H₂O), and light energy
• Products: Oxygen (O₂) and glucose (C₆H₁₂O₆)
• Chloroplasts are responsible
• Stroma refers to the space around the thylakoids
• Short wavelengths have the most energy
• Water (H₂O) is the source of released oxygen
• Colors are visible due to the reflection of certain light wavelengths
• The main product of light-dependent reactions is oxygen (O₂)

Calvin Cycle

• Carbon Fixation: RuBisCo attaches CO₂ to an organic molecule
• Reduction: ATP and NADPH convert molecules into G3P
• Regeneration: G3P is recycled into RuBP
• The final product is glucose (C₆H₁₂O₆)
• Carbon dioxide (CO₂) is required

Cellular Respiration & Fermentation

• Aerobic respiration generates ATP when oxygen is available
• Fermentation occurs when oxygen is not available
• The main purpose of fermentation is to regenerate NAD⁺ so glycolysis can continue
• Two types of fermentation: lactic acid fermentation and alcoholic fermentation
• Lactic acid and ATP are produced during lactic acid fermentation
• Ethanol, CO₂, and ATP are produced during alcoholic fermentation
• A facultative anaerobe can survive with or without oxygen

Energy & Metabolism

• Energy is the capacity to do work
• Kinetic energy is the energy of motion
• Potential energy is stored due to position or structure
• Chemical energy is potential energy stored in chemical bonds
• An exergonic reaction releases energy and occurs spontaneously
• An endergonic reaction absorbs energy and is non-spontaneous
• An anabolic reaction builds larger molecules from smaller ones, requiring energy
• A catabolic reaction breaks down molecules and releases energy
• Metabolism is the sum of all chemical reactions in an organism
• Activation energy is the minimum energy required to start a chemical reaction
• An enzyme is a protein that speeds up chemical reactions by lowering activation energy
• A substrate is the reactant that an enzyme acts upon
• The active site of an enzyme is the region where the substrate binds to the enzyme
• The first law of thermodynamics states that energy cannot be created or destroyed, only transferred or transformed
• The second law of thermodynamics states that every energy transfer increases entropy (disorder) in the universe
• ATP powers cellular work by releasing energy when a phosphate group is removed (ATP → ADP + Pi)
• Enzymes speed up reactions by lowering the activation energy

Study notes cover photosynthesis, the Calvin cycle, cellular respiration, and fermentation. Photosynthesis uses carbon dioxide, water, and energy to produce oxygen and glucose. The Calvin cycle uses carbon fixation, reduction, and regeneration to produce glucose. Aerobic respiration generates ATP in the presence of oxygen, while fermentation occurs without oxygen.