FAQs on Cell Cycle & its Phases Video Lecture - Biology for ACT
1. What is the cell cycle and what are its phases? |
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Ans. The cell cycle refers to the series of events that take place in a cell leading to its division and the formation of two daughter cells. The cell cycle consists of four main phases: G1 (gap phase 1), S (synthesis phase), G2 (gap phase 2), and M (mitotic phase). During G1, the cell grows and prepares for DNA replication. S phase involves DNA replication, where the genetic material is duplicated. In G2, the cell continues to grow and prepares for cell division. Finally, M phase includes mitosis, where the duplicated DNA is divided equally between the two daughter cells.
2. What happens during the G1 phase of the cell cycle? |
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Ans. The G1 phase, also known as gap phase 1, is the first phase of the cell cycle. During this phase, the cell grows in size and prepares for DNA replication. It synthesizes proteins and organelles required for cell division. The G1 phase is a crucial checkpoint where the cell checks for any DNA damage or other anomalies. If everything is normal, the cell proceeds to the S phase for DNA replication. If there are any issues, the cell may enter a resting state called G0 or undergo programmed cell death.
3. What is the significance of DNA replication during the S phase of the cell cycle? |
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Ans. The S phase, or synthesis phase, is the stage of the cell cycle where DNA replication takes place. DNA replication is crucial as it ensures that each daughter cell receives an identical copy of the genetic material. It involves the unwinding of the DNA double helix, separation of the strands, and the synthesis of new complementary strands. DNA replication occurs with high accuracy, thanks to various proofreading and repair mechanisms. Without proper DNA replication during the S phase, the resulting daughter cells may have incomplete or damaged genetic material.
4. What happens during the M phase of the cell cycle? |
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Ans. The M phase, or mitotic phase, is the final phase of the cell cycle. It includes mitosis, the process of dividing the duplicated genetic material and other cellular components equally between the two daughter cells. Mitosis consists of several stages: prophase, metaphase, anaphase, and telophase. During prophase, the chromosomes condense, the nuclear envelope disintegrates, and the spindle apparatus forms. In metaphase, the chromosomes align at the cell's equator. Anaphase involves the separation of sister chromatids, and telophase marks the formation of two new nuclei. Finally, cytokinesis occurs, dividing the cytoplasm and completing cell division.
5. What is the importance of the G2 phase in the cell cycle? |
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Ans. The G2 phase, or gap phase 2, is a critical stage in the cell cycle. It follows DNA replication in the S phase and precedes mitosis in the M phase. During G2, the cell continues to grow, synthesizes necessary proteins, and prepares for cell division. The G2 phase acts as another checkpoint where the cell ensures that DNA replication has occurred correctly and that there are no lingering errors or damage. If any issues are detected, the cell cycle may be arrested, allowing for DNA repair or triggering programmed cell death. The G2 phase also helps coordinate the transition from DNA replication to mitosis, ensuring proper cell division.