Lesson 6 of 66 in this sequence

Not completed yet

Saved on this device only — not synced to an account yet.

Learning path

Step 6 of 66

Continue the sequence

ResumeReturn to this step ReviewRevisit the core idea RemediateGet repair practice Next stepChoose the next lesson manually

Completion

Review objectives and instruction
Complete the activity with manual learner confirmation
Answer every understanding-check item
Show completion feedback and reward only after the learner finishes the check

Progress

Step 6/66
15 content types
AI help source context available
Auto-advance blocked

Review objectives and instruction

AI help

Available only with source grounding, privacy limits, age controls, and measurement.

AI source context

Cells: The Tiny Building Blocks of Life · All living things are made of one or many cells, the smallest unit of life

Evidence: local lesson AI-help metadata only; source-grounding, privacy, age-safety, and measurement hooks do not prove real model quality, production telemetry, child AI approval, or AI tutor production readiness

Production AI readiness not claimed

AI source context

Assessment shape

Local lesson assessment shape is complete.

Local shape only; production answer-attempt telemetry, live ownership/RLS evidence, mastery interpretation, release, and production readiness are not claimed here.

Objectives: 5
Activity: Prompt ready
Quiz items: 3 items, 3 answer keys, 3 explanations
Reward: Completion reward ready

Assessment progress stays manual: do not auto-advance through uncertain answers, failed writes, consent, media, payment, learner choice, or AI-assisted checks.

Learning-loop evidence: Content-map contract only; persistence and production learner-progress writes require route/API evidence.

Manual policy: assessment, media, consent, payment, learner choice, failed writes, and AI-uncertain help stay under learner control.

Prerequisite: Complete or review Body Parts That Help Plants and Animals Survive; Use with parent or guardian controls for child learners

AI guardrails

Privacy

Do not send raw child free text without consent
Use source excerpts and non-identifying progress state only
Asset is not registry-gated

Age safety

Apply kids audience controls before AI-help claims
Keep child learner AI paths behind guardian/product review evidence before readiness claims

Measurement

Log AI help usage by surface and asset slug
Evaluate answer quality against source-grounded rubric before production-readiness claims
Tie remediation prompts to completion, retry, or review outcomes

Local AI-help guardrails only; they do not prove guardian approval, production telemetry, model evaluation, release, deployment, or AI tutor production readiness.

Source and rights

Source path: koydo-app/scripts/curriculum-authoring
License: ai-generated-koydo
Attribution: Attribution decision needs owner review
AI provenance: claude-opus-4-8

Source review gates: attribution_missing

Local source evidence only; this does not prove publication rights, attribution approval, AI provenance clearance, release, deployment, or production readiness.

Route review

Current route: /library/kids/biology/en/lesson/cells-building-blocks-of-life
Route source: Fallback route needs owner canonical review
Candidate route: /library/kids/biology/en/lesson/cells-building-blocks-of-life

Local route evidence only; fallback candidates need owner-approved canonical route policy before route writes, production discoverability, or readiness claims.

Content gates: canonical_target_web_missing_uses_library_fallback

lessonslessonslesson objectivesmedia scenesdrillspractice setsquizzesfeedbackcharacterscitationsconcept mapsprogressresumereviewremediationnext steps

Cells: The Tiny Building Blocks of Life

with Atlas

Atlas the friendly explorer kneels in a sunny garden, holding a big magnifying glass over a green leaf, with tiny glowing brick-like cells visible inside the leaf and a curious ladybug nearby.

Define a cell as the smallest unit of life
Identify that all living things are made of cells
Compare living things made of one cell with those made of many cells
Give two examples of many-celled living things
Give two examples of one-celled living things

Key terms

Cell: The smallest living part of a living thing.
Microscope: A tool that makes tiny things look big.
Bacterium: A tiny living thing made of one cell.
Many-celled: A living thing built from lots of cells.

Cells Are Building Blocks

Cells are like tiny building blocks for living things. Think about a toy castle made from lots of little blocks stacked together. Your body works the same way, but with cells instead of blocks. Each cell is super small, much too small to see with just your eyes. Yet when trillions of cells join together, they build a whole living thing like you, a tree, or a puppy.

One Cell Or Many Cells

Some living things are made of just one single cell. A bacterium is one cell, and an amoeba is one cell. These are so tiny that you need a microscope to see them at all. Other living things, like a goldfish, an oak tree, or you, are made of many cells working together. Big or small, one cell or trillions, every living thing is built from cells.

Cells Work As A Team

Inside your body, cells do not work alone. They work together as a big team. Some cells help you see, some help your heart beat, and some help your muscles move. When cells team up, they can do amazing jobs that one cell could never do by itself. That is why a living thing made of many cells can grow, run, and play.

Worked examples

Is an oak tree one cell or many?

An oak tree is huge and you can see it with your eyes.
Things big enough to see are made of many cells.
So the oak tree is a many-celled living thing.

Answer: An oak tree is made of many cells.

Why do we need a microscope to see a bacterium?

A bacterium is made of just one tiny cell.
One cell is far too small for our eyes to see.
A microscope makes tiny things look big enough to see.

Answer: Because one cell is too small to see without a microscope.

Hi explorer, I'm Atlas! Grab your magnifying glass, because today we shrink down very small. Every living thing around you, like trees, fish, your pet, and YOU, is built from tiny pieces called cells. A cell is the smallest part of a living thing that is still alive. Think of cells like building blocks. A toy castle is made of many little blocks stacked together. In the same way, your body is made of trillions of cells — that is a million million, all working as a team! Some living things are made of just one single cell, so small we need a microscope to see them. A bacterium is one cell. An amoeba is one cell. Others, like a dog, a sunflower, or you, are made of trillions of cells! Whether one cell or many, every living thing needs cells. If something is alive, it is made of cells. That is the big idea. As you sort the living things below, ask yourself: is this something I could only see under a microscope, or is it big enough to see with just my eyes?

Activity

Sort each living thing into the one-celled or many-celled group

Practice

Name one living thing made of many cells.

Why can you not see a single cell with your eyes?

Common mistakes to avoid

Only animals are made of cells.Every living thing, including plants, is made of cells too.
A person is just one cell.A person is made of trillions of cells working together.

Check your understanding

What is the smallest unit of life?

Which statement about living things is true?

A friend says 'A person is made of just one cell.' Is that right?

Recap

Cells are the smallest living building blocks. Some living things are made of just one cell, and others are made of trillions. Every living thing, big or small, is built from cells.

Reflect

What surprised you most about how tiny cells are?