The function of chloroplasts in plant cells is:

• A. They perform photosynthesis to produce sugars for the plant.
• B. They store lipids for energy.
• C. They perform cellular respiration in animal cells.
• D. They are the site of protein synthesis.

Answer: (A)

Chloroplasts carry out photosynthesis, converting light energy into chemical energy stored as sugars. They use light to drive the production of ATP and NADPH, which power the Calvin cycle that fixes carbon dioxide into sugar molecules like glyceraldehyde-3-phosphate, eventually forming glucose and other carbohydrates that fuel the plant’s growth and metabolism. The organelle’s structure supports this: thylakoid membranes host the photosystems and electron transport chain for the light-dependent reactions, while the stroma contains the enzymes of the carbon-fixation steps.

Lipid storage is not the main role of chloroplasts; lipids are stored in lipid droplets or seeds. Cellular respiration in animal cells happens in mitochondria, not chloroplasts. And while chloroplasts do possess their own ribosomes and can synthesize some proteins, their primary function is energy capture via photosynthesis, not protein synthesis.