Given below are the sketches of two types of cells A and B
a) Which one of these is a plant cell? Give reason in support of your answer.
b) List the cell structures which are common to both the types.
c) Name the structures found only in plant cells and those found only in animal cells.

Hint: Cells are the most fundamental structural and functional unit of life. They are the building blocks of all living organisms. They convert nutrients from the food into energy and also give structure and support to the organisms. All the cells contain a fluid called cytoplasm, which is enclosed by a membrane. The cytoplasm contains biomolecules like nucleic acid, proteins and sugar. Several organelles are also embedded in the cytoplasm.

Complete answer:
a) Cell B is the plant cell in the given diagram. Plant cells are usually rectangular in shape with a cell wall. Animal cells are irregular and don't have a cell wall. It can be seen that cell A has no cell wall and is round in shape. Hence, cell A must be an animal cell and cell B is a plant cell.

b) Plant cells and animal cells share many structures in common. They are mitochondria, nucleus, cytoplasm, endoplasmic reticulum, ribosomes and Golgi apparatus. These organelles perform the same functions in animal cells as well as in plant cells.

c) Plant cells and animal cells have some unique specialized organelles. Chloroplasts are present in plant cells but are absent in animal cells. Chloroplasts contain chlorophyll which is important for the process of photosynthesis. Through photosynthesis plants make their own food. The animal cell contains centrosomes and cilia which are absent in plant cells. Centrosomes help in cell division while cilia help in locomotion.

Note:
Another similarity in plant cell and animal cell is that they are both eukaryotic cells. Eukaryotic cells are characterized by their true nucleus and membrane bound organelles. Fungi and protozoans are also included in this category. The other type, prokaryotic cells, have no true nucleus. Their genetic material is freely suspended inside the cell. Archaea, cyanobacteria and bacteria come under this category.