Mitochondria
Mitochondria release energy from food as ATP.
About this topic
Mitochondria are the cell's powerhouses, where aerobic respiration releases energy from glucose as ATP. They have a smooth outer membrane and a highly folded inner membrane (cristae) that increases surface area for the enzymes of the electron transport chain, enclosing a matrix with enzymes and their own DNA.
Cells with high energy needs, such as muscle, sperm and liver cells, contain many. Mitochondria are inherited from the mother, and are thought to originate from engulfed bacteria.
A marathon runner's muscle cells contain thousands of mitochondria, while a skin cell might contain far fewer. Inside each one, glucose products are broken down in the matrix and the electron transport chain on the cristae produces most of the ATP, using oxygen as the final electron acceptor. That is why you breathe harder when exercising: your mitochondria are demanding more oxygen.
Mitochondria have their own small circular DNA and ribosomes, a clue supporting the endosymbiotic theory, and they are inherited almost entirely from the mother. Faulty mitochondria cause serious inherited diseases affecting muscles and nerves. A very common misconception is that mitochondria make energy; strictly, they convert energy stored in food into the usable form ATP, because energy cannot be created.
Key ideas
- Inner membrane folds called cristae
- Own small DNA
- Called the powerhouse
Quick check
Use cases: where Mitochondria helps
- Homework: review the key idea behind Mitochondria before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Mitochondria without notes.
- Visual learning: play with the interactive lab to see how Mitochondria changes when you adjust its inputs.
- Teaching a friend: explain Mitochondria in your own words, then compare your version with the key ideas.
Biology underpins medicine, farming, conservation and biotechnology.
Frequently asked questions
What is Mitochondria?
Mitochondria release energy from food as ATP.
What will I learn in Mitochondria?
Inner membrane folds called cristae. Own small DNA. Called the powerhouse.
Is Mitochondria part of Biology?
Yes. It is one of 150 Biology topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Mitochondria lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Mitochondria?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.