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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
Distinguish cytokinesis from karyokinesis.
What is G0 (quiescent phase) of cell cycle?
Name the phase of the cell cycle at which the following event occurs:
Crossing over between homologous chromosomes takes place.
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)
Name the stage of mitosis in which chromosomes are arranged on the equator of spindle:
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.
Cell division cannot be stopped in which phase of the cell cycle?
Mitosis is characterised by ______.
Label the diagram and also determine the stage at which this structure is visible.
Two key events take place, during S phase in animal cells, DNA replication and duplication of centriole. In which parts of the cell do events occur?
Comment on the statement – Telophase is reverse of prophase.
Name the phase of the cell cycle at which the following event occurs:
Chromosomes are moved to spindle equator.
Spindle fibers attach to kinetochores of chromosomes during ______.
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:
