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प्रश्न
What is the cell theory? Who propounded it and when?
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उत्तर
All animals and plants are composed of cells, which serve as the units of structure and function. This, in short, is called the Cell Theory,
Cell theory was propounded by Theodor Schwann and Matthias Schleiden in the year 1839 and was modified by Rudolf Virchow in 1858.
APPEARS IN
संबंधित प्रश्न
Carry out the following osmosis experiment:
Take four peeled potato halves and scoop each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now,
- Keep cup A empty
- Put one teaspoon of sugar in cup B
- Put one teaspoon salt in cup C
- Put one teaspoon sugar in the boiled potato cup D.
Keep these for two hours. Then, observe the four potato cups and answer the following:
- Explain why water gathers in the hollowed portion of B and C.
- Why is potato A necessary for this experiment?
- Explain why water does not gather in the hollowed-out portions of A and D.
Differences between light microscope and electron microscope.
All life starts as _________.
State whether the following statement is true (T) or False (F):
Genes are located on a chromosome.
Try to find the names of four cell organells hidden in this maze, (hint: The hidden words can appear horizontally or vertically; forwards or backward or even mixed up). Write them in the lines provided. For example : “NUCLEUS” in the last row, seven backward letters.
| A | J | F | B | H | E | M | O | E | L | O | U | C | A | V |
| H | V | L | E | U | C | O | P | L | A | S | T | N | O | E |
| C | H | R | O | M | O | P | L | A | S | T | X | T | E | R |
| S | U | E | L | C | U | N | W | P | L | A | S | T | I | D |
Justify the statement "cell is the basic unit of life"
Expand - ER
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.
