3. Cells are so tiny that they can only be seen under a microscope. In 1590 Dutch lens grinder Hans and Zacharias Janssen made the first microscope by placing two lenses in a tube. A microscope magnifies objects by using lenses.

5. Typical plant cell Typical animal cell Nucleus: It controls all the activities of the cell including cell repair. It has thread-like structures called chromosomes which is made up of DNA. Genes are part of DNA which store information and pass it on from one generation to the next. Cytoplasm: This jelly like fluid is reduced to a thin layer due to a large vacuole. Here cell activities occur like breaking and making of materials. It contains other parts of cell such as nucleus and chloroplast. Cytoplasm: This is a jelly-like fluid which almost covers the whole cell. Here cell activities occur like breaking and making of materials. It contains other parts of cell such as nucleus. Chloroplast : Disc-like structures which contain a green pigment called chlorophyll to trap sunlight for carrying out photosynthesis. Chloroplast: Absent. Vacuole: Usually one single large vacuole which contains cell sap that has sugar, minerals and salts dissolved in water. It keeps the cell firm by taking in water. Vacuole: Numerous and small. Contain food water and waste materials. Cell wall: Firm and stiff structure made of cellulose and supports the cell. Cell Wall: Absent. Cell Membrane: Thin layer which controls the movement of materials (in and out of cell). Partially permeable.