Question

chloroplasts are organelles in plant and algal cells where ______.

the movement of gases into and out of cells is controlled

light is absorbed and photosynthesis is conducted

old organelles and toxic substances are broken down

cellular respiration takes place using oxygen

Explanation:

• Analyze each option:
• Option 1: Gas movement in/out of cells is controlled by cell membrane (like via diffusion or transport proteins), not chloroplasts.
• Option 2: Chloroplasts contain chlorophyll which absorbs light, and photosynthesis (converting light energy to chemical energy) occurs here. This matches the function of chloroplasts.
• Option 3: Breaking down old organelles and toxic substances is the role of lysosomes, not chloroplasts.
• Option 4: Cellular respiration using oxygen (aerobic respiration) mainly occurs in mitochondria, not chloroplasts.

Answer:

B. light is absorbed and photosynthesis is conducted