Every living cell is running right now — building proteins, producing energy, managing waste. Something inside is doing all of it. In this lesson, you'll find out what.
You already know a cell is the smallest unit of life. But life isn't passive — a cell is constantly building proteins, generating energy, cleaning out waste, reading its own DNA. Something inside is doing all of it. That something has a name.
Every structure marked ? inside this cell is running right now. Each one has a specific job — and without any single one of them, the cell would fail. Scroll down to find out what each one does and why it matters.
Before naming every organelle, here's a framework that will make them stick. A cell and a city solve the same problem: how do you keep a complex system running when every part depends on every other part? Find the city job first — then the organelle names will follow naturally.
Just as the Mayor's Office issues laws and decisions that guide the whole city, the nucleus contains the DNA "rulebook" that tells every organelle what to do.
Border control decides who and what enters or leaves the city. The cell membrane does the same — carefully regulating what passes in and out of the cell.
Ancient city walls kept the city standing tall and protected. The cell wall gives plant cells rigid structure and protection (only in plant cities!).
No city runs without electricity. The mitochondria generate ATP energy to power all of the cell's activities, just like a power station keeps the lights on.
Factories follow blueprints from headquarters to manufacture products. Ribosomes read instructions from the nucleus (DNA) to build proteins the cell needs.
A city's subway and road system moves people and goods around. The rough endoplasmic reticulum is the cell's highway, transporting proteins where they need to go.
The post office sorts, packages, and ships mail. Golgi bodies receive proteins from the ER, package them up, and ship them to the right destination inside or outside the cell.
Solar panels collect sunlight and convert it to usable energy. Chloroplasts do the exact same thing for plant cells through photosynthesis.
A city reservoir stores water for when citizens need it. Vacuoles store water, nutrients, and waste — plant cells have one giant central reservoir; animal cells have many smaller ones.
Every city needs garbage trucks and waste processing. Lysosomes are the cell's clean-up crew — breaking down waste, worn-out parts, and invaders to keep the cell healthy.
Streets connect every part of a city. The cytoplasm is the gel-like fluid that all organelles are suspended in — it lets nutrients and materials move freely from place to place.
Every one of those ? structures has a name and a job. Organelles are specialized parts inside a cell — each one doing something the cell can't survive without.
These organelles form the cell's physical boundaries and create the fluid environment that all other organelles live and move in.
This organelle contains the DNA — the master blueprint for everything the cell builds and does. Everything else in the cell answers to it.
Energy doesn't appear automatically — these organelles capture or convert it. One works in both plant and animal cells; the other only in plants.
These three organelles work as a team in sequence: build proteins from DNA instructions, transport them through the cell, then package and deliver them.
These organelles manage what the cell holds onto and what it breaks down and removes — keeping the cell's internal environment healthy.
Both are eukaryotic cells with a nucleus and shared organelles — but they're not identical. Study the diagram below. The green labels mark something specific — what do you notice about which cell has them?
Green labels = structures found only in plant cells.
A rigid outer layer outside the cell membrane. Gives plant cells a boxy, fixed shape and structural support. Animal cells have only the flexible membrane.
Capture sunlight and convert it to glucose through photosynthesis. Plants make their own food — animal cells cannot, so they have no chloroplasts.
One giant storage space that takes up most of the plant cell's interior. Stores water and helps maintain the cell's rigid shape. Animal cells have many tiny vacuoles instead.
These are the eleven terms from this lesson. If any feel uncertain, click to jump back to where it was explained — then come back and take the quiz.
👆 Click any term to jump to its explanation in the lesson
10 questions on cell organelles and their functions. Fill in your info below — your score will be sent to your teacher when you submit.
The lesson is just the beginning — go deeper, test your skills, or see how it all connects.