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प्रश्न
Write short notes on the following.
Nucleus of a cell
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उत्तर
Nucleus of a cell: The nucleus is a spherical structure generally present at the centre of a cell. The nucleus is composed of the following components:
1) Nuclear membrane: It is a double-layered membrane which separates the contents of the nucleus from the cytoplasm. The nuclear membrane has nuclear pores that allow the transfer of specific substances in and out of the nucleus.
2) Nucleolus: It is a small spherical body that is not bound by any membrane.
3) Chromosomes: These are thread-like structures that carry genes. Genes contain information necessary for the transfer of characteristics from the parents to the offspring. Thus, chromosomes play an important role in the inheritance of characteristics.
संबंधित प्रश्न
Give a brief account of discovery of the cell.
A plant cell has a cell wall made of :
Match the name of the organelle given in Column A with its function given in Column B.
| Column A (Organelle) | Column B (Function) | ||
| 1 | leucoplast | a | help in cell division |
| 2 | nucleus | b | transport of material |
| 3 | ribosomes | c | making food |
| 4 | mitochondria | d | digesting foreign bodies |
| 5 | endoplasmic reticulum | e | storage of starch and proteins |
| 6 | golgi bodies | f | making the cell turgid |
| 7 | chloroplast | g | making proteins |
| 8 | centrosome | h | controlling all the vital activities of a cell |
| 9 | vacuole | i | releasing energy |
| 10 | lysosomes | j | synthesis of cell wall in a plant cell |
Name any five cell organelles.
What was the contribution of the following to our knowledge of cells?
Schleiden
Fill in the blank with a suitable word:
______ controls all the metabolic activities of the cell.
Who studied the cell first?
Which is the smallest cell?
The instrument used to observe the cell is _____
Robert Hooke saw many objects like Butterfly’s compound eyes, Bee’s wings, etc.
