Exploring Photosynthesis: Light Reactions and the Calvin Cycle

Photosynthesis consists of light-dependent and light-independent reactions. Light-dependent reactions convert light energy into chemical energy, producing oxygen, NADPH, and ATP in the thylakoid membrane. The Calvin cycle, or light-independent reactions, uses these high-energy molecules to produce glucose from CO2 and RuBP. Key components include photosystems, electron carriers, and ATP synthase. The process involves complex interactions between chlorophyll, electron transport chains, and proton gradients to synthesize energy-rich molecules.

What are the two main phases of photosynthesis?

• Photorespiration and photolysis

• Glycolysis and fermentation

• Light-dependent and light-independent reactions

• Calvin cycle and Krebs cycle

Where do the light-dependent reactions of photosynthesis occur?

• In the cytoplasm

• In the thylakoid membrane

• In the mitochondria

• In the stroma

What is the primary function of the Calvin cycle?

• To fix carbon dioxide into glucose

• To generate ATP

• To produce oxygen

• To release carbon dioxide

Which enzyme is responsible for carbon fixation in the Calvin cycle?

• ATP synthase

• Rubisco

• Cytochrome b6f

• Photosystem II

What is the role of chlorophyll in photosystem complexes?

• Harvesting light energy

• Transporting protons

• Splitting water molecules

• Releasing oxygen

Which complex in the electron transport chain adds protons to the lumen to build the gradient?

• ATP synthase

• Photosystem I

• Ferredoxin

• Cytochrome b6f

What is the final electron acceptor in the light-dependent reactions?

• Oxygen

• Water

• NADP+

• Carbon dioxide

What by-product is considered a waste product by the plant during the light-dependent reactions?

• NADPH

• Oxygen

• ATP

• Glucose

How many molecules of CO2 are needed to produce one molecule of glucose in the Calvin cycle?

• Two

• Twelve

• Three

• Six

Why must plants keep oxygen levels low in their leaves?

• To increase ATP production

• To prevent water loss

• To avoid Rubisco's oxygenation activity

• To enhance chlorophyll stability