Question: Why does a plant cell have one large vacuole?
Solution (explanation):
Remember that the plants contain membrane-enclosed vacuoles filled with
aqueous solutions containing many dissolved substances. Plant vacuoles have several functions:
1. Plant cells produce a number of toxic by-products and waste materials, many of which are simply stored within vacuoles. And since they are poisonous or distasteful, these stored materials deter some animals from eating the plants. Thus these accumulated wastes may contribute to plant survival.
2. In many plant cells, giant vacuoles take up more than 90 percent of the cell volume and grow as the cell grows. The dissolved substances in the vacuole, working together with the vacuolar membrane, provide the turgor, or stiffness, of the cell, which provides support for the structure of nonwoody plants. The presence of the dissolved substances causes water to enter the vacuole, making it swell like a balloon.
3. Some pigments in petals and fruits are contained in vacuoles.
These pigments are visual cues that help attract the animals that assist in pollination or seed dispersal.
4. In some plants, the vacuoles contain enzymes that hydrolyze seed proteins into monomers that a developing plant embryo can use as food.
Answer: from numeral 2, we can conclude the correct answer is:
Plant cells have a large vacuole due to the amount of water the cell must hold to maintain its shape. The water in the vacuole creates something called Turgor Pressure.