9th Class Science Notes in English chapter 5 Fundamental Unit of Life : Cell.
📚 Chapter - 5 📚
🔹 Fundamental Unit of Life : Cell 🔹
✔ The Cell Theory :-
🔹 Two biologists, Schleiden and Schwann (1838) gave the Cell theory which states that :
▶ (i) All plants and animals are composed of cells.
▶ (ii) Cell is the basec unit of life.
▶ (iii) All cell arise from pre-existing cells.
✔ Types of organisms :-
🔹 On the basis of no. of Cells, Organisms are of two types:
▶ (i) Unicellular Organism
▶ (ii) Multicellular Organism
▶ (i) Unicellular Organism:- These organisms are single celled which perform all the functions.
Example:- Amoeba, Paramecium, Bacteria.
▶ (ii) Multicellular Organism:- Many cells grouped together to perform different function in the body and also form various body parts.
Example:- Fungi, Plants, Animals.
🔹 The shape and size of cell are different according to the kind of function they perform. There is division of labour in cells.
🔹 Each cell has certain kind of cell organelles to perform different type of function like mitochondria for respiration.
✔ Types of cells :-
🔹 There are two types of cells:
▶ (i) Prokaryotes
▶ (ii) Eukaryotes