Match List I with List II
LIST I                                                                                                     LIST II
A. S-Phase of cell division                                                I. Quiescent phase
B. G2 Phase                                                                           II. DNA of parent cell is replicated
C. M Phase                                                                            III. New proteins are synthesized and the cell approximately doubles in size
D. GO Phase                                                                         IV. Two daughter cells are produced.
Choose the correct answer from the options given below:
1. A-I, B-III, C-IV, D-II
2. A-II, B-IV, C-III, D-I
3. A-I, B-III, C-II, D-IV
4. A-II, B-III, C-IV, D-I

Cell Cycle Phases and Their Functions:

Introduction

The cell cycle is a fundamental biological process that allows cells to grow, replicate, and divide. It consists of different phases, each with a specific role in ensuring accurate DNA replication and cell division. Understanding these phases is crucial for studying cell biology, cancer research, and molecular genetics.

In this article, we will match the phases of the cell cycle with their respective functions and explore their significance.

Correct Answer: Option 4: A-II, B-III, C-IV, D-I

Keyphrase: Understanding the Phases of the Cell Cycle

1. S-Phase (Synthesis Phase)

• During S-Phase, the DNA of the parent cell is replicated, ensuring that each daughter cell receives an identical copy of genetic material.

• Key Features:

  • DNA replication occurs.

  • Histone proteins are synthesized.

  • Chromosomes become duplicated but are still held together as sister chromatids.

• Importance: Essential for genetic stability and preparation for mitosis.

2. G2 Phase (Growth Phase 2)

• The G2 phase follows DNA replication and is the last phase before mitosis.

• Key Features:

  • The cell grows in size.

  • New proteins and enzymes required for mitosis are synthesized.

  • The cell checks for DNA damage and repairs errors before entering mitosis.

• Importance: Ensures that cells are fully prepared for division.

3. M Phase (Mitosis or Meiosis Phase)

• The M Phase is the stage where the cell divides into two daughter cells.

• Key Features:

  • Includes prophase, metaphase, anaphase, and telophase.

  • Cytokinesis (cytoplasmic division) also occurs.

  • Each daughter cell receives a complete set of chromosomes.

• Importance: Allows for growth, tissue repair, and reproduction.

4. G0 Phase (Quiescent Phase)

• The G0 phase is a resting state where cells exit the cycle and do not divide.

• Key Features:

  • Cells are metabolically active but do not undergo division.

  • Some cells, like nerve and muscle cells, remain in G0 permanently.

  • Other cells, like liver cells, can re-enter the cycle if needed.

• Importance: Prevents unnecessary cell division and conserves energy.

Applications and Significance of Cell Cycle Study

1. Cancer Research

   • Cancer cells bypass cell cycle regulation, leading to uncontrolled division.

   • Studying the G1 and G2 checkpoints helps in designing anticancer drugs.

2. Genetic Disorders

   • Errors in DNA replication (S-phase) can cause genetic mutations and diseases like Down syndrome.

3. Stem Cell and Regenerative Medicine

   • Understanding G0 phase re-entry helps in tissue regeneration and wound healing.

4. Antibiotic and Drug Development

   • Some drugs target bacterial cell division by inhibiting DNA replication (S-phase) or mitosis (M-phase).

Conclusion

The cell cycle is an essential process that ensures accurate DNA replication and cell division. Each phase plays a crucial role in maintaining genetic stability and tissue homeostasis. Understanding these phases is vital for research in cancer therapy, genetics, and biotechnology.

For more information on cell biology, biotechnology, and exam preparation (CSIR NET, GATE, IIT JAM, DBT BET JRF), visit Let’s Talk Academy.