What are mitochondria?
Mitochondria are important parts of our cells because they take food and make energy that the rest of the cell can use.
Animals and plants are made up of many complex cells called eukaryotic cells. Inside these cells are structures that perform special functions for the cell called organelles. The organelle that is responsible for producing energy for the cell is the mitochondria.
How many mitochondria are in a cell?
Different types of cells have different numbers of mitochondria. Some simple cells contain only one or two mitochondria. However, complex animal cells that need a lot of energy, like muscle cells, can have thousands of mitochondria.
The main function of mitochondria is to produce energy for the cell. Cells use a special molecule for energy called ATP. ATP stands for adenosine triphosphate. The ATP for the cell is made within the mitochondria. You can think of the mitochondria as the energy factory or power plant of the cell.
Mitochondria produce energy through the process of cellular respiration. Respiration is another word for breathing. The mitochondria take food molecules in the form of carbohydrates and combine them with oxygen to produce the ATP. They use proteins called enzymes to produce the correct chemical reaction.
Mitochondria have a distinct structure that helps them to generate energy.
- Outer membrane - The outside is protected by an outer membrane that is smooth and varies in shape from a round blob to a long rod.
- Inner membrane - Unlike other organelles in the cell, mitochondria also have an inner membrane. The inner membrane is wrinkled with lots of folds and performs a number of functions to help make energy.
- Cristae - The folds on the inner membrane are called cristae. Having all these folds helps to increase the surface area of the inner membrane.
- Matrix - The matrix is the space inside the inner membrane. Most of the proteins of the mitochondria are in the matrix. The matrix also holds ribosomes and DNA that is unique to the mitochondria.
In addition to producing energy, mitochondria perform some other functions for the cell including cellular metabolism, the citric acid cycle, producing heat, controlling the concentration of calcium, and producing certain steroids.
Interesting Facts about Mitochondria
- They can quickly change shape and move around the cell when needed.
- When the cell needs more energy, the mitochondria can reproduce by growing larger and then dividing. If the cell needs less energy, some mitochondria will die or become inactive.
- Mitochondria are very similar to some bacteria. For this reason, some scientists think that they originally were bacteria that were absorbed by more complex cells.
- Different mitochondria produce different proteins. Some mitochondria can produce hundreds of different proteins used for various functions.
- In addition to energy in the form of ATP, they also produce small amounts of carbon dioxide.
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