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प्रश्न
Who proposed the Cell theory? Explain the main points of this theory.
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उत्तर
In 1839, M.J. Schleiden and T. Schwann proposed the cell theory. This was further expanded by Virchow in 1858.
The main features of the cell theory as known at present are:
(i) All living organisms are composed of cells. Hence cell is the structural unit of living organisms.
(ii) All cells arise from pre-existing cells of a similar kind by cell division.
(iii) The chemical composition and metabolism of all cells are basically alike.
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संबंधित प्रश्न
State the difference between eukaryotes and prokaryotes
The cell organelle that helps in the respiration of the cell is :
Do you think the cells of an elephant would be larger than the cells of a rat? Explain briefly.
Who coined the term “cell” ?
Fill in the blanks:
Organisms which are made up of a single cell are called ______ organisms.
What is the function of the following?
Mitochondria
What is a chromosome?
Match the items in column A with the appropriate items in column B:
| column A | column B |
| 1. Platform or workplace for the synthesis of proteins | a. Golgi complex |
| 2. A powerhouse of cells | b. Ribosomes |
| 3. Help in the formation of cell plate during cell division | c. Chloroplast |
| 4. Site for photosynthesis | d. Mitochondria |
| 5. Control tower of cell | e. Chromosomes |
| 6. A structure bearing genes | f. Nucleus |
When will you use a simple microscope and when, a compound microscope? Explain in detail how you will use them.
Under the microscope, Priya observes a cell that has a cell wall and distinct nucleus. The cell that she observed is
