Mitochondria
Biology: Cambridge International A Level, topic 12.2.5
Function of Mitochondria
Mitochondria are often called 'energy factories' of a cell because they make adenosine triphosphate (ATP), which is the cell's main energy-carrying molecule.
Adenosine triphosphate (ATP)
- ATP represents the short-term stored energy of the cell.
- Cellular respiration is the process of making ATP using the chemical energy found in glucose and other nutrients.
- In mitochondria, this process uses oxygen and produces carbon dioxide as a byproduct.
Mitochondria in muscle cells
- Muscle cells have very high concentrations of mitochondria producing ATP.
- This is because muscle cells need a lot of energy in order to keep the body moving, so a lot of cellular respiration happens in these cells.
Structure of Mitochondria
Mitochondria have a specific structure which allows them to perform their functions in cellular respiration.
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Double membrane
- Mitochondria are oval-shaped organelles which have their own ribosomes, DNA and a double membrane.
- Each membrane is a phospholipid bilayer embedded with proteins.
- The space between the membranes is called the intermembrane space.
Inner membrane
- The inner membrane contains folds, called cristae, which increase its surface area.
- This is important because ATP synthesis takes place on the inner membrane.
- The space inside the inner membrane is called the mitochondrial matrix, which also contains mitochondrial DNA.
Test yourself on Mitochondria
Why are mitochondria often called the 'powerhouse' of the cell?
What does ATP stand for?
Which of these reactions is used to produce ATP in mitochondria?
What is the space between the mitochondrial membranes called?
Where is mitochondrial DNA found?