JSS 1: Living things (II)
Cell
The cell is the basic structural and functional unit of life.
Unicellular organisms
Unicellular organisms are organisms with only one cell e.g. Bacteria, Diatom, Amoeba, Paramecium, Euglena, Chlamydomonas, etc.
Multicellular organisms
Multicellular organisms are organisms that are made up of many cells e.g. Human beings, goats, lions, mosquitoes, rats, etc
Animal cell
Cell organelles are special and organized structures present in living cells.
Examples of Cell organelles and their functions
1. Nucleus: It helps in the transfer of genetic materials in the form of DNA or RNA and also controls the activity of all other organelles
2. Cell membrane: It encloses the cell and its components from the external environment.
3. Cell Wall: It protects and maintains the shape of the cell.
4. Chloroplast: It is the primary center of photosynthesis.
5. Cytoplasm: protects genetic materials as well as other organelles from damage
6. Smooth Endoplasmic Reticulum: It transports lipid
7. Rough Endoplasmic Reticulum: It transports protein
8. Golgi Body(Golgi apparatus): It helps in directing proteins and lipids to their destination
9. Lysosome: It helps intracellular digestion.
10. Mitochondria: It helps in the synthesis of energy in the form of ATP.
11. Ribosomes: It is the site of protein synthesis in all living organisms.
12. Vacuole: It acts as a storage for nutrients as well as waste materials to protect the cell from toxicity.
Assignment
1. What is photosynthesis?
2. Write out the full meaning of the following: (I) ATP (II) ADP (III) DNA (IV) RNA
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