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प्रश्न
While examining the mitotic stage in a tissue, one finds some cells with 16 chromosomes and some with 32 chromosomes. What possible reasons could you assign to this difference in chromosome number. Do you think cells with 16 chromosomes could have arisen from cells with 32 chromosomes or vice versa?
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उत्तर
Cells with 16 chromosomes are produced by meiosis while that with 32 chromosomes are produced by mitosis.
- Cells with 16 chromosomes could have arisen from cells with 32 chromosomes through meiosis.
- Cells with 32 chromosomes could have arisen from cells with 16 chromosomes through fertilisation or syngamy.
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संबंधित प्रश्न
What is the average cell cycle span for a mammalian cell?
What is G0 (quiescent phase) of cell cycle?
Why is mitosis called equational division?
Analyse the events during every stage of cell cycle and notice how the following two parameters change.
- Number of chromosomes (N) per cell
- Amount of DNA content (C) per cell
Cells in the quiescent stage (Go)
Match List - I with List - II.
| List I | List II | ||
| (a) | S phase | (i) | Proteins are synthesized |
| (b) | G2 phase | (ii) | Inactive phase |
| (c) | Quiescent stage | (iii) | Interval between mitosis and initiation of DNA replication |
| (d) | G1 phase | (iv) | DNA replication |
Choose the correct answer from the options given below.
The centriole undergoes duplication during ______
Cell division cannot be stopped in which phase of the cell cycle?
Mitosis is characterised by ______.
Cells which are not dividing are likely to be at ______.
Which part of the human body should one use to demonstrate stages in mitosis?
It is said that the one cycle of cell division in human cells (eukaryotic cells) takes 24 hours. Which phase of the cycle, do you think occupies the maximum part of cell cycle?
Label the diagram and also determine the stage at which this structure is visible.
Name the phase of the cell cycle at which the following event occurs:
Centromere splits and chromatids separate.
Name the phase of the cell cycle at which the following event occurs:
Pairing between homologous chromosomes takes place.
Following are the stages of cell division:
- Gap 2 phase
- Cytokinesis
- Synthesis phase
- Karyokinesis
- Gap 1 phase
Choose the correct sequence of stages from the options given below:
Statement I: During GO phase of cell cycle, the cell is metabolically inactive.
Statement II: The centrosome undergoes duplication during S phase of interphase.
In the light of the above statements, choose the most appropriate answer from the options given below:
Match List I with List II:
| List I | List II |
| A. M Phase | I. Proteins are synthesised |
| B. G Phase | II. Inactive phase |
| C. Quiescent stage | III. Interval between mitosis and initiation of DNA replication |
| D. G, Phase | IV. Equational division |
Choose the correct answer from the options given below:
