Question

plants play an important role in the carbon cycle by producing carbohydrates. which of the following organelles enables plants to make carbohydrates from carbon dioxide and water?
a. a cell wall
b. a central vacuole
c. a chloroplast
d. a nucleus

Explanation:

• Cell wall: Provides structural support and protection for the plant cell. It has no role in carbohydrate synthesis from carbon dioxide and water.
• Central vacuole: Mainly functions in storage (e.g., storing water, ions, and nutrients) and maintaining turgor pressure in the plant cell. Not involved in carbohydrate production.
• Chloroplast: Contains chlorophyll. It is the site of photosynthesis, where plants use light energy to convert carbon dioxide ($\ce{CO2}$) and water ($\ce{H2O}$) into carbohydrates (such as glucose, $\ce{C6H12O6}$) and oxygen ($\ce{O2}$). The general photosynthesis equation is $6\ce{CO2}+6\ce{H2O}\xrightarrow[\text{chlorophyll}]{\text{light energy}}\ce{C6H12O6} + 6\ce{O2}$.
• Nucleus: Controls cellular activities by housing the cell's genetic material (DNA). It is not directly involved in the biochemical process of making carbohydrates from $\ce{CO2}$ and $\ce{H2O}$.

Answer:

C. A chloroplast