Do all cells need a mitochondria?

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Cell Mitochondria

What are mitochondria?

Mitochondria are important parts of our cells because they generate energy from food that the rest of the cell can use.

Table of Contents Show

Cell Mitochondria
Mitochondria - Turning on the Powerhouse
Using Oxygen to Release Energy
Related Video...
Is there any cell without mitochondria?
What if a cell has no mitochondria?
Why do some cells have no mitochondria?

Organelle

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.

Energy Factory

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.

Respiration

Mitochondria produce energy through the process of cellular respiration. 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.

Mitochondrion Structure

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.

Other Functions

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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Mitochondria - Turning on the Powerhouse

Mitochondria are known as the powerhouses of the cell. They are organelles that act like a digestive system which takes in nutrients, breaks them down, and creates energy rich molecules for the cell. The biochemical processes of the cell are known as cellular respiration. Many of the reactions involved in cellular respiration happen in the mitochondria. Mitochondria are the working organelles that keep the cell full of energy.

Mitochondria are small organelles floating free throughout the cell. Some cells have several thousand mitochondria while others have none. Muscle cells need a lot of energy so they have loads of mitochondria. Neurons (cells that transmit nerve impulses) don’t need as many. If a cell feels it is not getting enough energy to survive, more mitochondria can be created. Sometimes a mitochondria can grow larger or combine with other mitochondria. It all depends on the needs of the cell.

Mitochondria are shaped perfectly to maximize their productivity. They are made of two membranes. The outer membrane covers the organelle and contains it like a skin. The inner membrane folds over many times and creates layered structures called cristae. The fluid contained in the mitochondria is called the matrix.

The folding of the inner membrane increases the surface area inside the organelle. Since many of the chemical reactions happen on the inner membrane, the increased surface area creates more space for reactions to occur. If you have more space to work, you can get more work done. Similar surface area strategies are used by microvilli in your intestines.

What’s in the matrix? It's not like the movies at all. Mitochondria are special because they have their own ribosomes and DNA floating in the matrix. There are also structures called granules which may control concentrations of ions. Cell biologists are still exploring the activity of granules.

Using Oxygen to Release Energy

How does cellular respiration occur in mitochondria? The matrix is filled with water and proteins (enzymes). Those proteins take organic molecules, such as pyruvate and acetyl CoA, and chemically digest them. Proteins embedded in the inner membrane and enzymes involved in the citric acid cycle ultimately release water (H2O) and carbon dioxide (CO2) molecules from the breakdown of oxygen (O2) and glucose (C6H12O6). The mitochondria are the only places in the cell where oxygen is reduced and eventually broken down into water.

Mitochondria are also involved in controlling the concentration of calcium (Ca2+) ions within the cell. They work very closely with the endoplasmic reticulum to limit the amount of calcium in the cytosol.

Chalk Talk: Mitochondria (US-NSF Video)

Encyclopedia.com:
http://www.encyclopedia.com/topic/mitochondria.aspx#2
Wikipedia:
http://en.wikipedia.org/wiki/Mitochondrion
Encyclopædia Britannica:
http://www.britannica.com/EBchecked/topic/386130/mitochondrion

Is there any cell without mitochondria?

As the only cell which does not contain or have the mitochondria is the red blood cell. Red blood cell does not contain organelles like nucleus and mitochondria. Hence the red blood cell does not use any of the oxygen they transport.

What if a cell has no mitochondria?

Without mitochondria (singular, mitochondrion), higher animals would likely not exist because their cells would only be able to obtain energy from anaerobic respiration (in the absence of oxygen), a process much less efficient than aerobic respiration.

Why do some cells have no mitochondria?

Prokaryotic cells are less structured than eukaryotic cells. They have no nucleus; instead their genetic material is free-floating within the cell. They also lack the many membrane-bound organelles found in eukaryotic cells. Thus, prokaryotes have no mitochondria.