The Cell — Class 6 Science MCQs

The Cell | NCERT CBSE Curriculum

Practice 100+ MCQs on The Cell for Class 6 Science. Covers cell structure, parts (cell membrane, cytoplasm, nucleus), plant vs animal cell, and cell discovery - with instant answers and performance report.

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Quick Revision: The Cell

  • Cell: The basic structural and functional unit of life. All living organisms are made up of cells.
  • Discovery: Robert Hooke (1665) first observed cells in a thin slice of cork using a self-designed microscope. He named them cells (meaning small rooms).
  • Unicellular vs Multicellular: Unicellular organisms (Amoeba, Paramecium, Bacteria) have a single cell. Multicellular organisms (humans, plants, animals) have many cells that perform specialized functions.
  • Cell Membrane: The outermost covering of an animal cell. It is semi-permeable and controls the entry and exit of substances.
  • Cell Wall: Present only in plant cells, outside the cell membrane. Made of cellulose. Provides rigidity, strength, and structural support.
  • Cytoplasm: The jelly-like substance between the cell membrane and the nucleus. Contains various organelles where life processes occur.
  • Nucleus: The control centre or "brain" of the cell. Contains genetic material (DNA/chromosomes) and regulates all cell activities. Enclosed by a nuclear membrane.
  • Plant vs Animal Cell: Plant cells have a cell wall, large central vacuole, and plastids (chloroplasts for photosynthesis). Animal cells lack these but have many small vacuoles.
  • Mitochondria: Powerhouse of the cell. Releases energy from food through cellular respiration.
  • Ribosomes: Site of protein synthesis.
  • Endoplasmic Reticulum (ER): Rough ER (with ribosomes) — protein synthesis. Smooth ER (without ribosomes) — lipid synthesis.
  • Golgi Apparatus: Modifies, packages, and transports materials within the cell.
  • Lysosomes: Suicidal bags of the cell. Digest foreign materials and worn-out organelles.
  • Vacuoles: Storage sacs for water, food, and waste. Plant cells have a single large central vacuole that maintains turgor pressure.
  • Plastids: Found only in plant cells. Chloroplasts (chlorophyll — photosynthesis), Chromoplasts (colour), Leucoplasts (storage).
  • Cell Division: Cells divide for growth, repair, and reproduction. Mitosis (identical daughter cells) and Meiosis (gamete formation).
  • Tissue: A group of similar cells performing a specific function forms a tissue. Organs are made of tissues working together.

Chapter Summary: The Cell

The cell is the basic structural and functional unit of all living organisms. Discovered by Robert Hooke in 1665, cells can be unicellular (single-celled organisms like Amoeba) or multicellular (humans, plants). Every cell has a cell membrane (semi-permeable outer covering), cytoplasm (jelly-like fluid containing organelles), and a nucleus (control centre containing genetic material). Plant cells additionally have a cell wall made of cellulose for structural support, plastids (chloroplasts for photosynthesis), and a large central vacuole for storage and turgor pressure.

The cytoplasm contains various organelles each performing specific functions: mitochondria (energy release), ribosomes (protein synthesis), endoplasmic reticulum (transport), Golgi apparatus (packaging), lysosomes (digestion), and vacuoles (storage). Cells divide through mitosis (growth and repair) and meiosis (gamete formation). A group of similar cells working together forms a tissue, and multiple tissues combine to form organs. Understanding the cell is fundamental to understanding all life processes.

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