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Learn Cell Biology

Look inside the smallest unit of life and see how it really works.

Free to start. Built from a single prompt. No credit card.

Cell biology studies the cell, the basic unit of every living thing, and how its parts work together. A cell is a crowded, busy system: membranes control what gets in, ribosomes and the endoplasmic reticulum build proteins, the Golgi sorts and ships them, mitochondria make ATP, and a cytoskeleton moves everything around. The subject then explains how cells divide, signal to each other and die on purpose. Learnr builds a personalized cell biology course from a single prompt and teaches it through short, interactive lessons that adapt to you.

How to learn Cell Biology, step by step

Learn cell theory and how cells are seen. Start with cell theory, then compare light, fluorescence and electron microscopy and what each can show. Look at cheek cells or onion skin yourself if you can, and compare prokaryotic and eukaryotic cells by size and structure.
Master membranes and transport. Learn the fluid mosaic model of the phospholipid bilayer and its proteins. Sort transport into diffusion, facilitated diffusion, osmosis, active transport with pumps like the sodium-potassium pump, and endocytosis and exocytosis.
Tour the organelles by job. Group organelles by function: information (nucleus, ribosomes), manufacturing and shipping (rough and smooth ER, Golgi, vesicles), breakdown (lysosomes, peroxisomes) and energy (mitochondria, chloroplasts). Then follow one secreted protein along the whole route.
Learn the cytoskeleton and cellular energy. Compare microfilaments, intermediate filaments and microtubules and the motor proteins that walk along them. Then see how mitochondria make ATP and why the inner membrane folds increase their capacity.
Study the cell cycle and its controls. Learn G1, S, G2 and M, the stages of mitosis and the checkpoints driven by cyclins and cyclin-dependent kinases. Connect checkpoint failure and lost apoptosis to cancer, and contrast mitosis with meiosis.
Add signaling and review with diagrams. Follow a signal from receptor to second messenger to response, using a G protein-coupled receptor as the example. Redraw a labeled cell from memory each week and keep up short daily Learnr reviews.

What you'll learn

Describe the structure and function of each major organelle
Explain membrane structure and passive and active transport
Follow a protein from ribosome through the ER and Golgi to its destination
Describe the cell cycle, mitosis and its checkpoints
Explain how cells signal, make ATP and undergo apoptosis

What's inside your Cell Biology course

A sample path Learnr builds for Cell Biology. Your real course adapts to your goal and level.

1. Cell theory, microscopy and cell types
2. Membranes and transport
3. Organelles and the endomembrane system
4. The cytoskeleton and cell movement
5. Cellular energy and signaling
6. The cell cycle, cell death and cancer

How long does it take to learn Cell Biology?

An introductory cell biology course takes about 2 to 3 months at 3 to 5 hours a week. Prior chemistry makes membranes and energy much easier, and a university-level molecular cell biology course is a demanding semester or more.

What you need before you start

Introductory biology and basic chemistry, especially molecules, bonds and the idea of energy. Some knowledge of proteins and DNA helps for the protein sorting and cell cycle units.

Common mistakes to avoid

Learning organelles as a disconnected list. Follow processes, like making and exporting a protein, so you see how organelles work together.
Picturing the cell as a static diagram. Inside a real cell, molecules move constantly and organelles shift, divide and fuse.
Confusing mitosis and meiosis, or chromosomes and chromatids. Draw the chromosomes at each stage and count them to keep them straight.

How Learnr builds your course

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Cell Biology questions, answered

What is the difference between cell biology and molecular biology?

Cell biology focuses on the structure and behavior of cells and organelles. Molecular biology focuses on DNA, RNA and proteins and how genetic information is used. Modern courses often combine them.

Do I need chemistry for cell biology?

Basic chemistry helps a lot, since membranes, enzymes and ATP are chemistry problems at heart. Learnr can review the chemistry you need as each topic comes up.

Why do plant and animal cells differ?

Plant cells have a rigid cell wall, chloroplasts for photosynthesis and a large central vacuole. Animal cells lack these but have structures like centrioles and more varied shapes.