1. Cell
Smallest structural and functional unit of life.
| Discovery of cell and its components | Cell theory | Types of cells on basis of organization | Types of organisms on basis of number of cells |
| Robert Hooke (1665) first observed dead cells in a cork slice. | Formated by M.J Schleiden (1838) and Theodor Schwann (1839) expended by R. Virchow (1855) all cells arise from pre-existing cells. | Prokaryotic cells organism without definite nucleus of bacteria. | Unicellular (single cell) |
| A. V. Leeuwenhoek (1674) discovered free living cells in pond water. | All living organisms are made up cells. | Eukaryotic cells organisms without definite nucleus, e.g., fungi, plants , animals | |
| Robert Brown (1831) discovered the nucleus in the cell. | The cells is the basic structural and functional unit in all organisms. | ||
| Purkinje (1839) coined the term ‘protoplasm’. | All cells arise from pre-existing cells. |
2. Cell
2.1 Cell Wall (Plant Cell)
- Made up of cellulose, porous to micro and macro moleculose like sugar and starch.
2.2 Cell membrane
- Made up of proteins and lipids.
- Selectively permeable in nature.
- Singer and Nicolson gave the fluid mosaic model of plasma membrane.
2.3 Protoplasm
- Cytoplasm
- ➥ Cell organelles
- (i) Mitochondria ‘Power house of the Cell’
- (ii) Ribosome site for protein synthesis
- (III) Chloroplast (in green plants)
- (a) Grana
- (a) (i) Contain chlorophyll
- (b) Stroma
- (b) (i) Contain enzymes
- (iv) Endoplasmic Reticulum
- (c) Rough Endoplasmic Reticulum [RER] (with ribosomes)
- (d) Smooth Endoplasmic Reticulum [RER] (no ribosomes)
- (v) Golgi body (Processing and packaging proteins and other molecules to form cell secretions
- Nucleus
- ➥ Nucleoplasm
- (i) Fluid medium (containing nucleotides and enzymes)
- (ii) Chromatic substances/ chromoromes
- ➥ Nuclear membrane
2.4 Vacuole (Plant cell)
- Contains water, nutrients, mineral, salts, waste (with greeneous substances)
3. Osmosis
“Osmosis is a process by which the molecules of a solvent pass from a solution of low concentration to a solution of high concentration through a semi-permeable membrane.”
| Isotonic solution | Same concentration of solutes both inside and outside the cell. | Cell will stay same size | |
| Hypertonic solution | Higher solute concentration outside the cell then inside | Cell becomes flaccid or undergoes plasmolysis | Exosmosis |
| Hypotonic solution | Higher solute concentration inside the cell than outside. | Cell becomes turgid or undergoes deplasmolysis | endosmosis |
