Cell of Class 9
The cell is a fundamental structural and functional unit of living organisms. Living organism are distinct in form, structure, behavior, heridity and development. Cells within a single plant or animal vary widely in structure and function, they all represent units of living material and have important properties in common. New cell arise from pre-existing cells and a zygote has ability to form the whole individual. Thus physiology and function of an organism is governed by the sum total of activities and interactions of its constituent cells.
Living being is formed by small units which are called as cells. Each cell is complete in itself. In unicellular organisms they function freely the different and various activities but in multicellular organisms they control the activities combinable. Each cell has a cell membrane which covers its protoplasm. This protoplasm. However in plant cells fungi bacteria the cell is also surrounded by a cell wall. Protoplasm is the site of living activities of every cell.
- All living forms are composed of microscopic units called as “Cells”.
- A cell is the basic structural and functional unit of all life forms.
- Study of structure and composition of cell is called as “Cytology”.
- Cell was first observed by “Robert Hooke” in a dead cork slice in the year 1665. He described about this in his book “Micrographic”
- The term protoplasm was coined by purkinje in 1839.
- Protoplasm was discovered by “Felix Dujardin” and named as sarcode.
- It’s consistency differs under different condition. It exists in sol-gel states.
- Protoplasm is an aggregate of various chemicals such as water, ions, salts and other organic molecules like proteins, carbohydrates, fats, nucleic acids, vitamins etc.
- The word cell was derived from a Greek word “Cellulae” which means small room.
- First living cell was discovered by A.V. Leeuwenhoek.
NCERT solutions for class 9 Science prepared by pw will help you to solve your NCERT text book exercise.
- CELL STRUCTURE
- HISTORICAL BACKGROUND OF CELL
- Cell structure and function
- TYPES OF CELL & ORGANISM
- DETAILED STRUCTURE OF CELL
- CELL MEMBRANE
- CELL WALL
- ENDOPLASMIC RETICULUM
- GOLGI APPARATUS
- LYSOSOMES (ENZYMES PACKETS)
- VACUOLES (NON-CYTOPLASMIC INCLUSIONS)
- CELL DIVISION
- solved question
- Exercise 1 for Cell of class 11
- Exercise 2 for Cell
- Exercise3 for Cell of class 11
- Exercise 4(Fill in the blanks) for Cell of class 11
- Exercise 5(True-False) for Cell of class 11