Biology Resources

Learn biology at your own pace

Our goal is to help you understand biology better. These free public videos, interactives, and explanations are here whenever you need them—even if you don’t have time for a tutoring session with us. Pick your course level, choose a question, and open a resource from educators, universities, museums, and science organizations.

Start with these 10 common study questions for each level. Pause a video to take notes, sketch a process, and explain the idea in your own words.

Middle school biology

Build your foundation in cells, living things, inheritance, and ecosystems.

1. What makes something alive?

Watch video: What Makes Something Living?
Khan Academy · YouTube · Free public learning resource

2. What do the organelles inside a cell do?

Watch video: Eukaryopolis: The City of Animal Cells
Crash Course Biology · YouTube · Free public learning resource

3. How are plant and animal cells different?

Watch video: Intro to Cells: Animals & Plants
FuseSchool · YouTube · Free public learning resource

4. How do diffusion and osmosis move materials across membranes?

Watch video: Transport in Cells: Diffusion and Osmosis
FuseSchool · YouTube · Free public learning resource

5. How do plants make food through photosynthesis?

Watch video: Photosynthesis
Khan Academy · video · Free public learning resource

6. How do cells release energy from food?

Watch video: Cellular Respiration: Crash Course Biology
Crash Course · YouTube · Free public learning resource

7. How do Punnett squares predict inherited traits?

Watch video: Punnett Squares
FuseSchool · YouTube · Free public learning resource

8. How does natural selection change populations?

Watch video: Natural Selection: Life’s Way of Stayin’ Alive
Crash Course Biology · video · Free public learning resource

9. How does the body keep its internal conditions stable?

Watch video: Feedback in Living Systems
Khan Academy · YouTube · Free public learning resource

10. How does energy move through a food chain?

Watch video: Food Webs
Nature WY · PBS video · Free public learning resource

High school biology

Connect cellular processes with genetics, evolution, and the living world.

1. How do prokaryotic and eukaryotic cells differ?

Watch video: Prokaryotic vs Eukaryotic: The Differences
FuseSchool · YouTube · Free public learning resource

2. How does membrane structure control what enters and leaves a cell?

Watch video: Cell Membranes: How Does Stuff Get Into Your Cells?
Crash Course Biology · video · Free public learning resource

3. What happens during glycolysis in cellular respiration?

Watch video: Cellular Respiration
Bozeman Science · YouTube · Free public learning resource

4. How does photosynthesis store energy from sunlight?

Watch video: Photosynthesis: Where Did the Energy in Your Pizza Come From?
Crash Course Biology with HHMI BioInteractive · video · Free public learning resource

5. How does the cell cycle produce new cells?

Watch video: Cell Cycle, Mitosis and Meiosis
Bozeman Science · YouTube · Free public learning resource

6. Why does sexual reproduction create genetic variation?

Watch video: Meiosis (Updated)
Amoeba Sisters · YouTube · Free public learning resource

7. How do Mendel’s laws explain inheritance?

Watch video: Punnett Squares
FuseSchool · YouTube · Free public learning resource

8. How is information in DNA copied into RNA?

Watch video: Protein Synthesis: Transcription and Translation
Amoeba Sisters · YouTube · Free public learning resource

9. How do natural selection, genetic drift, and gene flow change populations?

Watch video: Natural Selection: Life’s Way of Stayin’ Alive
Crash Course Biology · video · Free public learning resource

10. Why is less energy available at higher trophic levels?

Watch video: The Higher We Go, the Lower It Gets
Spotlight Earth · PBS video · Free public learning resource

AP Biology

Go deeper into mechanisms, models, and the connections behind common AP Biology questions. These videos and learning resources supplement your class materials.

1. How do polarity and hydrogen bonding explain water’s properties?

Watch video: The Unexpected Truth About Water: Crash Course Biology #21
Crash Course Biology with HHMI BioInteractive · YouTube · Free public learning resource

2. How do temperature, pH, and inhibitors affect enzyme activity?

Watch video: Enzymes
Bozeman Science · YouTube · Free public learning resource

3. How can solute concentrations predict osmosis and changes in cell volume?

Watch video: Osmosis and Water Potential (Updated)
Amoeba Sisters · YouTube · Free public learning resource

4. How does a proton gradient drive ATP synthesis?

Watch video: Oxidative Phosphorylation and the Electron Transport Chain
Khan Academy · YouTube · Free public learning resource

5. How do the light reactions produce ATP and NADPH?

Watch video: Photosynthesis: Where Did the Energy in Your Pizza Come From?
Crash Course Biology with HHMI BioInteractive · video · Free public learning resource

6. How do signal transduction pathways amplify a message?

Watch video: Cell Signaling: The Big Picture for AP Bio Students
Science Music Videos / Learn-Biology · YouTube · Free public learning resource

7. How do checkpoints and cyclins regulate the cell cycle?

Watch video: Cell Cycle Regulation
Shomu’s Biology · YouTube · Free public learning resource

8. How do genetic linkage and crossing over explain recombination?

Watch video: Chromosomal Crossover in Meiosis I
Khan Academy · video · Free public learning resource

9. How can Hardy–Weinberg equations help analyze a population?

Watch video: Solving Hardy–Weinberg Problems
Bozeman Science · YouTube · Free public learning resource

10. How do exponential and logistic population growth differ?

Watch video: Population Growth II
MIT OpenCourseWare · lecture video · Free public learning resource

Still stuck? Let’s work through it together.

If a video or explanation still doesn’t make sense, contact Bio Mentor Network. Tell us which topic is confusing and what you have tried. We can help break it down, ask questions, and build understanding.

Get biology help · contact@biomentornetwork.org