The Science of Photosynthesis: From Sunlight to Energy

Professor Dave explains photosynthesis, a process where plants convert sunlight, water, and CO2 into energy. The process consists of light reactions and the Calvin cycle, occurring in chloroplasts. Light reactions produce ATP and NADPH, while the Calvin cycle synthesizes organic molecules. Photosynthesis is crucial for the food chain and is the reverse of cellular respiration.

What is the primary source of energy for plants?

• Carbon dioxide

• Water

• Sunlight

• Soil nutrients

What are the two main stages of photosynthesis?

• Light reactions and Krebs cycle

• Light reactions and Calvin cycle

• Calvin cycle and Glycolysis

• Electron transport chain and Calvin cycle

Where do the light reactions of photosynthesis occur?

• In the cytoplasm

• In the thylakoid membrane

• In the chloroplast membrane

• In the stroma

What molecule is produced as a byproduct of the light reactions?

• Water

• Glucose

• Carbon dioxide

• Oxygen

What is the role of chlorophyll in photosynthesis?

• To transport electrons

• To produce glucose

• To absorb water

• To absorb sunlight

What is the main purpose of the Calvin cycle?

• To release oxygen

• To fix carbon dioxide into organic molecules

• To produce ATP

• To absorb sunlight

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

• ATP synthase

• Rubisco

• Chlorophyll

• NADP+ reductase

How many ATP molecules are required to produce one G3P molecule in the Calvin cycle?

• Three

• Twelve

• Six

• Nine

How does photosynthesis compare to cellular respiration?

• Both build sugars

• Both degrade sugars

• Photosynthesis builds sugars, while cellular respiration degrades them

• Photosynthesis degrades sugars, while cellular respiration builds them

What is the final product of the Calvin cycle that can be used to form glucose?

• Oxygen

• G3P

• NADPH

• ATP