CHAPTER S: FUNDAMENTALS OF LIFE
INTRODUCTION - Every organism in this universe are made of tiny basic structural units called cells. - Cells were discovered by Robert Hooke in 1665. - Cells are the building blocks of an element that cannot be seen with naked eyes but can be seen under a microscope. - Every Living-element is made up of numerous tiny cells. - There are some single celled organisms as well that Live on their oun. - Organisms can be classified into unicellular and multicellular organisms depending upon the number of cells present in their body
HUMAN CELLS Neuron ColumnarWhite blood epithelial cells cells Red blood cells Smooth muscle cells VARIOUS CELLS OFTHE LIVING BODY
Unicellular organisms Unicellular organisms are composed of single cell. Cell membrane The single cell constitutes the structure and entire function of the organism Contractle vacuole excretes water and waste) - For example, Amoeba found in marine areas or ood being engulfed by areas of decaying water is a microorganism composed of single cell that determines the shape of the ood vacuole (digests food) amoeba. Chlamydomonas is another example of unicellular organism found in marine regions. - Paramecium is also unicellular organism.
MULTICELLULAR ORGANISMS Multicellular organisms are composed of many cells. The Labour of performing different functions is divided between the various cells in these organisms. Some multicellular organisms have different cells. For example, Human beings have different cells of different shapes and sizes in their body to perform different functions.
SUMMA R y 1. All the iving organisms are made up of fundamental unit of life called" cell" 2. The cell is a Latin word for "a little room" 3. The scientist Robert Hooke saw a little room in the cork (the bark of a tree) resembled the structure of a honeycomb. The use of the word "Cell" to describe these units is used till this day in Biology as" Cell Biology". 4. The Compound Microscope consist eye piece,objective lens and condenser to observe a cell after putting a drop of Safranin (for plant cell) and methylene blue (for animal cell). (Please refer to Fig. 5.1: Compound Microscope NCERT Book Page-57) 5. The scientist Leeuwenhoek saw free living cells in the pond water for the first time.( father of microbiology) 6. The scientist Robert Brown discovered the nucleus in the cell. 7. The cell theory states that all the plants and animals are composed of cells, it was proposed by Schleiden and Schwann. 8. The cell theory was further expanded by Virchow by suggesting that all cells arise from the pre-existing cells" 9. The cells differ in size, shape, structure (Please refer to Fig. 5.2/5.3: Onion peel/Various cells in Human body, NCERT Book Page-57/58):Types of cells: Onion cells, Smooth muscle cell, Blood cells, Bone cell, Fat cell, Nerve cell, Ovum, Sperm etc. Each kind of cell performs specific function. 59 10. A single cell may constitute a whole organism as in Amoeba, Chlamydomonas, Paramecium and Bacteria; these are called as unicellular organisms. Whereas in multi-cellular organisms (Human beings) division of labor is seen
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