Tag: cell structure and organization

A plant cell is characterised by a single large sap vacuole. They enclose sap or water with dissolved inorganic and organic substances. It is surrounded by a membrane called as tonoplast. Plant cell vacuole maintains osmotic pressure for turgidity and osmosis. They also store useful as well as waste substances. The growth in terms of increase in size depends on the elongation of the cell. For elongation of the cell, the protoplasm needs to push against cell wall from inside. The generation of pushing force depends on the osmotic pressure created by substances stored in central vacuole. Thus, the correct answer is option D.

Tonoplast or vacuolar membrane is the living membrane of the vacuole. It separates the vacuolar contents from the cell's cytoplasm. It helps the vacuole in maintaining the osmoregularity inside the cell.

Vacuoles are the membrane-bound organelle mostly found in the plant cell. It is the centrally located large storage bubble in the plant cells and filled with cell sap. They provide osmotic pressure and turgidity to the plant cell. 

Vacuoles are storage bubbles found mostly in plant cells. These are used for storage of food or water. The vacuolar membrane is a single layered and is called as tonoplast. Osmotic pressure and turgidity is maintained by vacuoles. They store toxic metabolic by-products or end products of plant cells. Such vacuoles are thrown out of the cell by exocytosis. Thus, the correct answer is option D.

In a plant cell, the vacuoles are large and centrally placed organelle. Vacuoles typically contain salts, sugars and sometimes proteins and have a variety of secretory, excretory and storage functions. The vacuole may also be involved in the breakdown of old organelles or macromolecules and then recycling the products back to the rest of the cell. Thus, they are in large number in a cell adapted for waste storage and disposal.
So, the correct answer is option A.

• The cell sap is a non-living content of the vacuole. Cell sap is the fluid manufactured by the cytoplasm of the living plant cell.
•  Cell sap consists of water and various substances that are often in the form of a colloidal suspension. 
• On average, cell sap has twice the viscosity of water. 
• The cell sap contributes to the osmotic properties and turgor of the cell, and consequently, to the elasticity of plant tissues and organs. 

The vacuole is a membrane-enclosed fluid-filled sac found in plant cells that occupies a major part of the cell volume. It gives rigidity to the cell and hence to the plant by using water to develop a pressure called hydrostatic pressure. It stores nutrient and non-nutrients such as pigments and mineral ions. It also stores the cellular metabolic waste. Thus the correct answer is option C.

Vacuole is the characteristic feature of plant cell while absent in animal cell. The liquid substance present in the vacuole is called cell sap. The cell sap is mainly composed of water, sugar, salt, pigment- anthocyanin. Vacuole functions as store house for secretory and excretory substances. Thus option B is the correct answer.

• The function and significance of vacuoles vary greatly according to the type of cell in which they are present.
• In general, the functions of the vacuole include- Isolating materials that might be harmful or a threat to the cell. Containing waste products. 
• Containing water in plant cells. Maintaining internal hydrostatic pressure or turgor within the cell. Maintaining an acidic internal pH. 
• Allows plants to support structures such as leaves and flowers due to the pressure of the central vacuole etc.
  
  Therefore, the correct answer is option D.