Mitochondria organelles are the powerhouse of the cell.  Their main function is to produce energy for the cell.  The number of mitochondria within a cell varies depending on the cell type.

The mitochondria are the energy power house of the cell.

Function of Mitochondria

Like a power plant, the mitochondria produce energy for the cell to use

Like a power plant, the mitochondrion produce energy for the cell to use

Mitochondria organelles are tiny energy generators in the cell.  In fact, all of the cell’s energy comes from the hard working mitochondrion.  These pill shaped organelles take food and break it apart into water and carbon dioxide.  The broken down food then creates an enormous amount of energy for the cell.

Energy is produced from the production of ATP (adenosine triphosphate) molecules. The mitochondrion converts oxygen and nutrients within the cell into ATP molecules.  This process is also known as cellular respiration.

ATP molecules are the main energy-carrying molecules in your body.  Thus, it plays an important role in walking, standing, studying, thinking, and so much more.

For example, think of the power generators that produce electricity for our cities.  They break up fuel to create electricity for the entire city.  Similarly, the mitochondria are like the power generators for the cell.


3D illustration of multiple mitochondria in a cell

3D image of mitochondria in a cell

Number of Mitochondria in a Cell

Within living things, cells that are more active need more energy.  As a result, these cells have more mitochondria.  In a similar way, bigger cities need more power, and as a result, these cities have more power plants.

The number of mitochondria within a cell could vary from 0 to 10,000.  The quantity depends on the how much energy that type of cell needs.  For example, red blood cells do not contain any mitochondria.  However, muscle cells that require a lot of energy contain hundreds or even thousands of mitochondria.


Structure of Mitochondria

Image of a cross-section and structure mitochondrion organelle

Diagram of the Structure of Mitochondrion

With an electron microscope, you can observe a mitochondrion’s structure.  Biologists have discovered that the shape and function of the mitochondrion are different from cell to cell.  Most mitochondria are either sphere or rod-shaped.  However, others may look like sticks, rings, strings or onions. In fact, the mitochondrion can change their shape if they want!

Mitochondria have double membranes.  In simple words, they have two layers of skins. The outer membrane is the external boundary, and it determines the shape. The inner membrane is the internal skin, and it is the place where chemical reaction of energy production occurs.

The inner membrane has many irregular folds. These folds are called cristae. Cristae are very important because they increase the surface area of the inner membrane.  With more surface area, the mitochondria can have more chemical reactions.  And, more chemical reactions create more energy for the cell.

The space within the inner membrane is called the matrix. It contains enzymes, which helps the chemical reactions of energy production.  Inside the matrix, there are multiple loops of mitochondrial DNA, which contain genetic information. Biologists discovered that the mitochondrial DNA is very similar to bacterial DNA, and bacteria could possibly be the ancestor of mitochondria.


Written by: ChungLing Wong