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Helicase

Mitochondria

Convert energy from food into ATP, the cell's usable energy.Source: NHGRISource: Mitchell, 1961Source: Boyer, 1997

Step 4 of 7ReadingStructure

Inside the cell: mitochondria

Mitochondria turn the energy in food into a form the cell can use, a molecule called ATP.

Through cellular respiration, mitochondria use oxygen to break down fuel molecules and make most of a cell's ATP. They have their own small circle of DNA, and strong evidence indicates they descend from bacteria that lived inside ancestral cells.

Electron transport through protein complexes in the inner membrane pumps protons out of the matrix, creating an electrochemical gradient. ATP synthase, a rotary enzyme, uses the flow of protons back across the membrane to make ATP, the chemiosmotic mechanism Peter Mitchell proposed. Folds called cristae increase the inner membrane's area.

Structure

Outer and inner membranes; the inner membrane folds into cristae around a protein-rich matrix that holds mitochondrial DNA and ribosomes.

Key molecules
  • ATP
  • ATP synthase
  • Cytochrome c
  • NADH
  • Mitochondrial DNA

Related health conditions

  • MELAS. Caused by variants in mitochondrial DNA, most often the MT-TL1 gene (more than 80 percent of cases). Most people with MELAS inherit the altered gene from their mother.Source: MedlinePlus
  • Leber hereditary optic neuropathy. A condition caused by variants in mitochondrial DNA that affects the optic nerve and vision.Source: MedlinePlus

For learning only, not medical advice.

Explore mitochondria in the Cell Explorer

How Mitochondria connects

Mitochondria is part of

  • Level of life

    Cell

    The smallest unit that can live on its own. Every living thing is made of one or more cells.

    Open in Cell Explorer

Mitochondria is the site of

  • Process

    Cellular respiration

    Breaking down sugars and other fuels, mostly in mitochondria, to make ATP.

Mitochondria evolved from

  • Organism or group

    Bacteria

    Small single-celled organisms without a nucleus, found almost everywhere on Earth. Most bacteria in the human body are harmless, and some are helpful.

    Open in Microbe Lab

Mitochondria is described by

  • Idea or model

    Endosymbiosis

    Mitochondria and chloroplasts descend from bacteria that came to live inside other cells long ago.

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In the knowledge graphFind papers about Mitochondria

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Sources & further reading

The explanations on this page are our own summaries of these sources. Follow a link to read the original; if anything here disagrees with it, the original wins. How we choose and check sources.