Cell Structure and Function
The smallest unit that counts as alive — and the machinery packed inside it
Free trail · Science · ages 13–14 · 6 stations
Inside a Single Cell
A cell is not a bag of jelly with a dot in the middle. It is a compartmentalised chemical factory, and almost every compartment exists to keep one set of reactions away from another. Flip every card.
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Holds the DNA and controls which proteins are made. Calling it "the brain" is misleading — it gives no orders. It is a reference library the rest of the cell reads from, copying out one gene at a time as messenger RNA.
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"Powerhouse" is a slogan. The actual job is aerobic respiration: glucose + oxygen → carbon dioxide + water, with the released energy stored in about 30 molecules of ATP. ATP is the cell's rechargeable battery, not its food.
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Reads messenger RNA and links amino acids into a protein — the machine that turns a gene into a working molecule. Venkatraman Ramakrishnan shared the 2009 Nobel Prize in Chemistry for mapping its structure atom by atom.
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A double layer of fat molecules with proteins floating in it. It is selectively permeable — some things diffuse straight through, others need a protein channel or a pump. Every cell on Earth has one.
This is one station of 6 in the trail, and finishing the trail earns an Explorer badge. Create a free account to play the rest →
Inside the app
The station above is the real thing — and it is one of 6. Inside the app your child plays the whole trail — every station is something they touch, drag and try, each one earns a checkmark, finishing the trail awards an Explorer badge, and the Practice Zone builds a fresh set of questions every visit. Progress is saved to their player, so they can stop and pick it up later.
What your child does, station by station
Learning mode has no timers, no scores and no wrong answers — every station is something the child touches and moves. This trail is one of the free ones, so it opens on any account.
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Inside a Single Cell
Flip cards
A cell is not a bag of jelly with a dot in the middle. It is a compartmentalised chemical factory, and almost every compartment exists to keep one set of reactions away from another. Flip every card.
Flip every card. Each organelle is a compartment doing one chemical job.
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Plant, Animal or Both
Sorting baskets
Plant and animal cells share most of their machinery. The differences are few, but each one tells you something about how that organism makes a living.
Sort each structure by which kind of cell you would find it in.
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Why Cells Stay Small
Slider explorer
Here is the constraint that sets the size of almost every cell alive. A cell absorbs food and oxygen through its surface, but it has to supply its whole volume. Double the radius and the surface goes up 4 times — but the volume goes up 8 times. Slide it.
Slide the cell radius. Watch surface area and volume race each other.
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Structure and Job
Matching pairs
In biology, structure predicts function more reliably than almost anything else. Match each structure to the job its shape allows.
Match each structure to the job its shape makes possible.
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Cell Detective
Try it
These are the questions that separate memorising a diagram from understanding a cell.
Five questions where the obvious answer is not quite the right one.
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Practice Zone
Practice Zone
Ten questions matched to this topic — a proper practice set, fresh every time.
Ten questions on this topic. New ones every time you come back.
Free printable worksheet
Ten questions from this topic on one page, with an answer key at the bottom — a PDF you can print for homework, a car journey or a classroom. No account needed and nothing to sign up for. The Practice Zone in the app builds a fresh set every visit; this is a fixed set you can hold.
More Science for ages 13–14
💨 Tissues and Organ Systems · ❤ Human Physiology · 🧬 Genetics and Heredity · 🦕 Evolution and Natural Selection · 🦠 Microorganisms and Disease · ⚛️ Atomic Structure · 📋 The Periodic Table · 🔗 Chemical Bonding
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