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प्रश्न
Describe the events taking place during interphase.
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उत्तर
Even though it is referred to be the resting phase, the interphase is highly metabolically active. It is the period of time when the cell gets ready to divide by going through a systematic process of both cell growth and DNA replication.
G1 (Gap 1) phase
S (Synthesis) phase
G2 (Gap 2) phase
The G1 phase refers to the period between the mitosis of the preceding cell cycle and the commencement of DNA replication. In the G1 phase, the cell is metabolically active and undergoes continuous growth without DNA replication. The synthesis phase, or S phase, denotes the time frame in which DNA replication or synthesis occurs. DNA doubles in each cell throughout this period. In animal cells, centrioles duplicate in the cytoplasm while DNA replication takes place in the nucleus during the S phase. DNA synthesis ceases during the G2 phase, but protein and RNA synthesis continues as the cell grows in preparation for mitosis.
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संबंधित प्रश्न
Distinguish cytokinesis from karyokinesis.
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)
Most cytogenic activities occur during
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 ______.
Between a prokaryote and a eukaryote, which cell has a shorter cell division time?
Which of the phases of cell cycle is of longest duration?
Which tissue of animals and plants exhibits meiosis?
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.
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?
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:
Centromere splits and chromatids separate.
