The membrane around the vacuole is known as

Step 1: Analyze the question The question asks for the name of the membrane that surrounds the vacuole in a cell. This is mostly a plant cell topic, where the vacuole is large and prominent.

Step 2: Explain the concept The vacuole is a fluid-filled sac in the cytoplasm. It stores water, mineral salts, sugars, and waste products, and it helps maintain turgor pressure in plant cells. It is bounded by a single selectively permeable membrane called the tonoplast.

Step 3: Check each option

• A. Elaioplast: a type of plastid that stores oils and fats. It is not a membrane.
• B. Amyloplast: a type of plastid that stores starch. It is not a membrane.
• C. Tonoplast: the membrane surrounding the vacuole. This matches the question.
• D. Cytoplast: the whole contents of a cell inside the cell membrane, excluding the nucleus. It is not a vacuole membrane.

Step 4: Answer The correct answer is **C.

Tip: Remember that "tono-" relates to tension or tone, as in turgor and water balance. The tonoplast controls what enters and leaves the vacuole, which helps keep the cell firm. Also, any word ending in "-plast" that is not "tono-" refers to a plastid or cell part (such as chloroplast, amyloplast, or elaioplast), not a membrane.