The Fundamental Unit of Life Practice
Solve chapter-level practice questions for The Fundamental Unit of Life with reveal-only solutions and quick revision support.
Practice Set 1 — Cell Structure and Membranes
Discovery of the cell, prokaryotes vs eukaryotes, diffusion and osmosis.
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Practice Set 2 — Cell Organelles
Nucleus, ER, Golgi, mitochondria, plastids, vacuoles, lysosomes.
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Quick Q&A Before You Revise
Why is the cell called the structural and functional unit of life?
Structural — every living body is built of one or more cells. Functional — each cell can independently carry out the basic life activities (nutrition, respiration, excretion, growth). Below the cell level, life activities do not occur.
What would happen if the plasma membrane ruptures or breaks down?
The membrane controls what enters and leaves the cell. If it breaks, the cell cannot regulate its contents; substances leak out, unwanted materials enter, and the cell dies.
Why are lysosomes absent in prokaryotic cells but their function still managed?
Prokaryotic cells have no membrane-bound organelles at all, including lysosomes. Their smaller size and simpler organisation mean digestive enzymes can act in the cytoplasm directly.
How do substances like CO₂ and water move in and out of the cell?
Carbon dioxide moves by diffusion — from where it is in higher concentration to where it is lower. Water moves in and out by osmosis, across the selectively permeable plasma membrane, according to the solute concentrations inside and outside.