CBSE Class 9 Biology Chapter 5 The Fundamental Unit of Life — 20 MCQs with Answers

Understanding how cells were discovered and the development of Cell Theory is fundamental. Robert Hooke coined the term 'cell' in 1665 while observing cork under a microscope. Matthias Schleiden and Theodor Schwann proposed that all living organisms are made of cells. Rudolf Virchow later added that all cells arise from pre-existing cells. These historical milestones form the basis of modern cell biology and appear regularly in CBSE exams as factual recall or assertion-reason questions. The following MCQs test your knowledge of scientists, their contributions, and the tenets of Cell Theory.

Cells are broadly classified into prokaryotic and eukaryotic based on the presence of a membrane-bound nucleus. Prokaryotic cells (bacteria, cyanobacteria) lack a true nucleus and have DNA in a nucleoid region. They are small, simple, and lack membrane-bound organelles. Eukaryotic cells (found in animals, plants, fungi, protists) have a well-defined nucleus enclosed by a nuclear membrane and contain organelles like mitochondria, ER, and Golgi apparatus. Understanding this distinction is crucial for NCERT-based MCQs and helps you identify cell types in diagrams. The next four questions focus on structural and functional differences.

The plasma membrane (cell membrane) is a selectively permeable barrier made of a lipid bilayer with embedded proteins—the Fluid Mosaic Model. It regulates the entry and exit of substances, maintaining homeostasis. Small, non-polar molecules like oxygen and carbon dioxide pass through by diffusion, while larger or charged molecules require protein channels or active transport. Understanding selective permeability and the structure of the membrane is essential. These MCQs test your grasp of membrane composition, function, and the concept of diffusion across the membrane.

The cell wall is a rigid, non-living layer outside the plasma membrane in plant cells, fungi, and bacteria. In plants, it is made of cellulose and provides structural support, shape, and protection. The nucleus is the control centre of eukaryotic cells, enclosed by a nuclear envelope with pores. It contains chromosomes—structures made of DNA and protein that carry genetic information. The nucleolus inside the nucleus synthesizes ribosomal RNA. These structures are central to understanding cell organization and function. The following MCQs cover cell wall composition, nuclear structure, and the role of chromosomes.

Mitochondria are double-membrane organelles found in nearly all eukaryotic cells. They perform aerobic respiration, converting glucose and oxygen into ATP (the cell's energy currency) and releasing carbon dioxide and water. They have their own DNA and ribosomes, suggesting an evolutionary origin from ancient bacteria. Chloroplasts, found only in plant cells and some protists, contain chlorophyll and carry out photosynthesis—converting light energy, carbon dioxide, and water into glucose and oxygen. Both are energy-transforming organelles and crucial for life on Earth. These MCQs test your understanding of their structure, function, and evolutionary significance.

CBSE Class 9 Biology exams typically include 10–15 MCQs worth 1 mark each in the objective section. Strategic MCQ-solving can save time and improve accuracy. First, read each question carefully—watch for keywords like 'NOT', 'ONLY', or 'EXCEPT' that reverse meaning. Eliminate obviously wrong options to narrow your choice. If unsure, recall NCERT diagrams or definitions verbatim—CBSE strictly follows NCERT terminology. For assertion-reason questions, verify both statements independently, then check if the reason logically explains the assertion. Don't spend more than 30–40 seconds per MCQ; if stuck, mark it and return later. Cross-checking answers in the last 5 minutes can catch silly mistakes. Practising 50–100 MCQs from each chapter builds speed and confidence. CBSETUTOR.ai offers unlimited chapter-wise MCQ practice with instant explanations, photo-upload doubt solving, and personalized error tracking—all at a flat ₹999/month for Classes 6–12 with a 3-day free trial. Regular MCQ practice transforms exam anxiety into assured performance.