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What are cristae in a mitochondrion?
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mitochondrion
Mitochondria (red) are found throughout the cytoplasm of almost all eukaryotic cells (cell nucleus is shown in blue; cytoskeleton is shown in yellow).
In a mitochondrion, cristae are the elaborate folds of the inner membrane. These structures are essential to mitochondrial function because they dramatically increase the surface area of the inner membrane, providing more space for the enzymes and protein complexes involved in energy production.12
The cristae play a critical role in the following biological processes:
- ATP Synthesis: The inner membrane, including the cristae, houses the electron-transport chain and ATP synthetase complexes. These systems convert chemical energy into ATP, the primary energy currency of the cell.23
- Proton Gradient: During respiration, protons are pumped across the cristae from the matrix into the intermembrane space. Because the inner membrane is highly impermeable to ions, this creates an electrochemical gradient that powers the synthesis of ATP as protons flow back into the matrix through specialized enzyme complexes.23
- Metabolite Transport: Special carrier proteins located in the cristae facilitate the movement of charged metabolites into the matrix.2