Question

which events take place in the light - dependent reactions of photosynthesis?
light energy is converted to sugars; sugars are broken down for energy.
light energy is captured by plants; light energy is used to make sugar.
light energy is converted to chemical energy; chemical energy is used to make sugar.
light energy is captured by plants; light energy is converted to chemical energy.

Explanation:

In the light - dependent reactions of photosynthesis:

• Chlorophyll (in plants) captures light energy.
• Through a series of reactions (electron transport chain etc.), light energy is converted into chemical energy in the form of ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate).

Let's analyze each option:

• Option 1: Light energy is not converted to sugars in light - dependent reactions. Sugar formation (Calvin cycle) is in light - independent reactions. Also, sugar breakdown is cellular respiration.
• Option 2: Light energy is used to make sugar in light - independent reactions (Calvin cycle), not in light - dependent reactions.
• Option 3: Chemical energy (ATP and NADPH) from light - dependent reactions is used to make sugar in light - independent reactions (Calvin cycle), but the first part of the statement is about light - dependent reactions.
• Option 4: Light energy is captured by plants (by chlorophyll) and converted to chemical energy (ATP and NADPH) in light - dependent reactions.

Answer:

Light energy is captured by plants; light energy is converted to chemical energy.