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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
Write short notes on the following.
Nucleus of a cell
A plant cell has a cell wall made of :
Name the part of the cell concerned with the following :
Transmission of hereditary characters from parents to offspring
Justify the statement "cell is the basic unit of life"
Define the term cell? Also, describe types of cells.
What is the function of the following?
Cell membrane
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 |
the question has four options. Choose the correct answer:
Cell theory states
Answer the following question.
Who discovered cells, and how?
Matching:
| 1. | Discovery of cell | a. | Nerve cell |
| 2. | Unicellular organism | b. | spirogyra |
| 3. | Multicellular organism | c. | Robert Hooke |
| 4. | Longest cell | d. | Cyanobacteria |
| 5. | Prokaryotic cell | e. | Amoeba |
