Photosynthesis Light-Dependent Reactions Explained

Photosynthesis involves light-dependent reactions and the Calvin cycle. In chloroplasts, thylakoids and stroma play key roles. Light-dependent reactions convert light to chemical energy using photosystems. Photosystem 2 initiates electron transport, producing ATP and oxygen. Photosystem 1 re-energizes electrons to form NADPH, essential for sugar synthesis in the Calvin cycle.

What are the two main sets of reactions in photosynthesis?

• Calvin cycle and Krebs cycle

• Photolysis and electron transport

• Light-dependent reactions and Calvin cycle

• Glycolysis and fermentation

Where do the light-dependent reactions take place within the chloroplast?

• In the mitochondria

• In the ribosomes

• In the stroma

• In the thylakoids

What is the primary function of photosystem 2 in the light-dependent reactions?

• Synthesis of glucose

• Absorption of carbon dioxide

• Production of ATP only

• Splitting water molecules

What is produced as a byproduct of water molecule oxidation during photolysis?

• Carbon dioxide

• ATP

• Glucose

• Oxygen gas

What is the role of ATP synthase in the chloroplast?

• To synthesize ATP from ADP and inorganic phosphate

• To capture carbon dioxide

• To absorb light energy

• To transport electrons

How are low energy electrons re-energized in photosystem 1?

• By transferring to a higher energy state

• By absorbing more photons

• Through ATP

• By splitting water molecules

What molecule is reduced to form NADPH in the light-dependent reactions?

• O2

• CO2

• NADP+

• ATP

Where does the Calvin cycle occur within the chloroplast?

• In the mitochondria

• In the thylakoids

• In the stroma

• In the nucleus

What is the main purpose of the Calvin cycle in photosynthesis?

• To absorb light energy

• To synthesize glucose

• To generate ATP

• To produce oxygen

Which of the following is NOT a direct output of the light-dependent reactions?

• Oxygen

• ATP

• NADPH

• Glucose