This part explores the life cycle of a cell, including its growth, DNA replication, and division. This post contains Class 9 Biology Chapter 5 MCQs designed to help students understand mitosis, meiosis, the significance of the cell cycle, and stages like interphase and cytokinesis.
1. What is the sequence of events that a cell goes through from one division to the next?
- A. Photosynthesis
- B. Cell cycle ✅
- C. Mutation
- D. Translation
Explanation: The cell cycle is the complete series of events in a cell’s life, including growth and division.
2. Which phase of the cell cycle involves growth and normal cell functions?
- A. Interphase ✅
- B. Mitosis
- C. Cytokinesis
- D. Telophase
Explanation: Interphase is the non-dividing phase where the cell grows and prepares for division.
3. What process ensures that each daughter cell gets an identical set of chromosomes?
- A. Meiosis
- B. Mitosis ✅
- C. Fertilization
- D. Translation
Explanation: Mitosis divides the nucleus so that both new cells receive identical genetic material.
4. What is the correct order of mitosis stages?
- A. Prophase → Anaphase → Metaphase → Telophase
- B. Prophase → Metaphase → Anaphase → Telophase ✅
- C. Metaphase → Prophase → Telophase → Anaphase
- D. Telophase → Anaphase → Metaphase → Prophase
Explanation: The standard sequence of mitosis is Prophase → Metaphase → Anaphase → Telophase.
5. Which phase of mitosis involves chromosomes aligning at the center of the cell?
- A. Prophase
- B. Metaphase ✅
- C. Telophase
- D. Anaphase
Explanation: During metaphase, chromosomes line up in the middle before being pulled apart.
6. What is the role of centrioles during mitosis?
- A. Replicate DNA
- B. Control metabolism
- C. Organize spindle fibers ✅
- D. Break down membranes
Explanation: Centrioles help form spindle fibers that separate chromosomes during cell division.
7. During which phase does the nuclear envelope reappear?
- A. Anaphase
- B. Telophase ✅
- C. Prophase
- D. Metaphase
Explanation: Telophase is the final phase of mitosis where nuclear envelopes reform around chromosomes.
8. What is cytokinesis?
- A. Chromosome duplication
- B. Division of cytoplasm ✅
- C. DNA repair
- D. Protein synthesis
Explanation: Cytokinesis is the division of the cell’s cytoplasm, completing the formation of two daughter cells.
9. In which phase are sister chromatids pulled apart?
- A. Telophase
- B. Prophase
- C. Anaphase ✅
- D. Interphase
Explanation: During anaphase, sister chromatids separate and move to opposite ends of the cell.
10. What happens to DNA during the S phase of interphase?
- A. It is replicated ✅
- B. It breaks down
- C. It shrinks
- D. It divides
Explanation: In the S (synthesis) phase, DNA is duplicated to prepare for cell division.
11. Which type of cell division produces four genetically different cells?
- A. Mitosis
- B. Meiosis ✅
- C. Cytokinesis
- D. Budding
Explanation: Meiosis is a type of cell division that results in four genetically unique haploid cells.
12. What is the main purpose of mitosis in multicellular organisms?
- A. Sexual reproduction
- B. Growth and repair ✅
- C. Food production
- D. Mutation
Explanation: Mitosis allows for growth, replacement of damaged cells, and tissue repair in multicellular organisms.
13. What happens during G1 phase of the cell cycle?
- A. DNA is replicated
- B. Cell grows and performs normal functions ✅
- C. Chromosomes divide
- D. Spindle fibers form
Explanation: G1 is a part of interphase where the cell grows and performs metabolic functions.
14. Which stage marks the end of the cell cycle?
- A. S phase
- B. Interphase
- C. Cytokinesis ✅
- D. Metaphase
Explanation: Cytokinesis divides the cytoplasm, completing the cycle and producing two daughter cells.
15. Which process maintains chromosome number across generations?
- A. Fertilization
- B. Mitosis
- C. Meiosis ✅
- D. Transcription
Explanation: Meiosis reduces the chromosome number by half, ensuring consistency after fertilization.
16. What is the key feature of prophase?
- A. Chromosomes condense and become visible ✅
- B. Chromosomes line up
- C. Chromatids separate
- D. Nucleus reforms
Explanation: In prophase, chromatin condenses into chromosomes, and the nuclear envelope begins to break down.
17. Why is interphase the longest phase of the cell cycle?
- A. Because it includes division
- B. Because the cell prepares for division ✅
- C. Because chromosomes split
- D. Because centrioles form
Explanation: Interphase involves growth, DNA replication, and preparation for mitosis, which takes significant time.
18. During which stage do chromosomes first become visible under a microscope?
- A. Interphase
- B. Prophase ✅
- C. Telophase
- D. Anaphase
Explanation: Chromosomes condense and become visible during the early stage of prophase.
19. What is the importance of checkpoints in the cell cycle?
- A. Ensure correct progression through stages ✅
- B. Initiate meiosis
- C. Prevent transcription
- D. Stimulate mutations
Explanation: Checkpoints ensure that the cell only proceeds to the next stage when it is ready and error-free.
20. What type of cells undergo meiosis?
- A. Muscle cells
- B. Germ cells ✅
- C. Skin cells
- D. Blood cells
Explanation: Germ cells in reproductive organs divide by meiosis to form gametes (sperm and egg).