(a) Plant cells have big vacuoles full of cell sap that provide them turgidity and rigidity. Plant vacuoles store amino acids, sugars, various organic acids and some proteins.
(b) In unicellular organisms, they may serve the following purposes:
(i) Forming Food Vacuoles: In single-celled organisms like Amoeba, the food vacuole contains the food items that the Amoeba has ingested. The food items are digested by the enzymes later on.
(ii) Removal of excess water and wastes: In some unicellular organisms, specialised vacuoles play important roles in expelling excess water and some wastes from the cell.

Plastids are double membrane bounded structures which are found in plant cells only. Inside the plastid, a fluid material called stroma is present. In stroma, numerous membrane layers remain scattered. Plastids like mitochondria do not have cristae. They also have extra-nuclear DNA. There are two types of plastids- Leucoplasts and granules.

(i) Lysosomes contain powerful digestive enzymes capable of breaking down all organic material.
(ii) Lysosomes help to keep the cell clean by digesting worn out cell organelles and foreign material such as bacteria or food.
(iii) RER (Rough Endoplasmic Reticulum) makes the digestive enzymes present in the lysosomes.

Endoplasmic reticulum helps in the transport of substances between various regions of the cytoplasm or between the cytoplasm and the nucleus. Endoplasmic reticulum also functions as a cytoplasmic framework providing a surface for some of the biochemical activities of the cell. In vertebrates, SER present in the liver cells also plays an important role in detoxifying poisons and drugs.

Cell Theory: Schleiden and Schwann proposed that:
(i) all the plants and animals are composed of cells and that
(ii) the cell is the basic unit of life. Later on Virchow added that
(iii) all cells arise from pre-existing cells.

It performs the following functions in the plant cell:
(i) It gives a definite shape to the cell.
(ii) It provides rigidity and strength to the cell.
(iii) It protects the plasma membrane and inner cell organelles by bounding the cell from outside.
(iv) It allows cell of plants, fungi and bacteria to withstand very dilute external media without bursting.
(v) It helps in transport of the material in and out of the cell.
(vi) Cell wall maintains the shape of the cell when cytoplasm shrinkes away from cell wall during plasmolysis.
(vii) It prevents desiccation of cells.

1. When concentration of CO₂ is more inside the cell than outside, CO₂ diffuses from the cell to outside of cell. If CO₂ concentration inside the cell is less, CO₂ moves inside the cell from outside.
2. The water move in and out of the cell by the process of osmosis. Osmosis is the passage of water from a region of high water concentration through semi-permeable membrane (cell membrane) to a region of low concentration of water.

Ribosomes help in protein synthesis.

(i) Extracellular digestion. Sometimes lysosome enzymes are released outside the cell to break down extracellular material.
(ii) Digestion of foreign material. lysosomes also destroy and foreign material which enters inside the cell such as bacteria.
(iii) Cellular digestion. In damaged cells, ageing cells or dead cells lysosomes get ruptured, and enzymes are released. These enzymes digest their own cell.
Lysosomes contain about 40 hydrolytic enzymes. When the cell gets damaged, lysosomes burst and their enzymes digest their own cell. So, lysosomes are called 'suicide bags'.
Foreign materials entering the cell, such as bacteria or food, as well as old organelles end up in the lysosomes, which break them up into small pieces.

(i) Lysosomes are membrane-bound sacs filled with digestive enzymes.These enzymes are made by rough endoplasmic reticulum.
(ii) Lysosomes are a kind of waste disposal system of the cell.
(iii) During the disturbance in cellular metabolism, e.g. when a cell gets damaged, lysosomes present in the cell may burst and the enzymes digest the damaged cell. Hence, lysosomes are called as 'suicidal bags' of a cell.
(iv) Lysosomes break up the foreign materials entering into the cell, such as bacteria or food into smal piece

(i) We will give ORS (Oral Rehydration Solution) from time to time till we reach to doctor or doctor comes to attend the patient. ORS is available in powder form packed in sachets.
(ii) We can make ORS in home by the following way:
Ingredients
1. One level teaspoon of salt
2. Eight level teaspoon of sugar
3. One litre of clean drinking or boiled water and then cooled (5 cupfuls-each cup about 200 .ml.),
Preparation Method
Stir the mixture till the salt and sugar dissolve.
(a) Arrange community lectures, debates to sensitise harmful effects of dehydration of the body.
(b) Conveying importation of ORS and its preparation in home