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Mitochondria

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Last updated date: 01st Mar 2024
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A Detailed Overview of Mitochondria

We all eat our breakfast, dinner, and lunch, but have you ever wondered how we get energy from food? How can we use this energy?  Well, it is due to mitochondria. Mitochondria are important cell organelles in our body and are known as the powerhouse of cells. Different types of cells have different numbers of mitochondria. For example, simple cells have one or two mitochondria, whereas complex cells, such as plant or animal cells, have numerous mitochondria as they require more energy.


Plant cells have hundreds of mitochondria, while the number goes to thousands and lakhs for animal cells. Interestingly, the human body has 1,00,000 to 6,00,000 mitochondria in each cell which can produce 90% of the energy in the body to perform daily tasks. In this article, we will discuss the mitochondria diagram, function of mitochondria, and structure of mitochondria.


Mitochondria


Mitochondria 


What Are Mitochondria?

Mitochondria are the powerhouse of cells as they generate energy for cell functioning. The structure of mitochondria is unique. The mitochondrion is a rod or sausage-shaped structure found in animal and plant cells. It is a small organelle whose size is between 0.5 to 1 micrometre in diameter. Hence, it cannot be seen under a microscope unless stained. Unlike other organelles, it has two layers; inner and outer. Each layer performs different functions. 


Let us understand the structure with the mitochondria diagram. 


Structure of Mitochondria


Structure of Mitochondria 


Mitochondria Structure 

  • Outer Membrane - It is made of proteins. The membrane allows small protein-like molecules to pass through it. 

  • Intermembrane Space - It is the space between outer and inner membranes. 

  • Inner Membrane - This membrane is made of phospholipids and does not allow molecules to pass through it. Special transporters (carrier molecules) are required to transport substances. Here, ATP production takes place. 

  • Cristae - These are the irregular folds of the inner membrane. They increase the space for chemical reactions to take place by increasing the surface area of the membrane. 

  • Matrix - It is fluid within the inner membrane. This fluid has several enzymes required for ATP production. It also contains ribosomes, mitochondrial DNA, inorganic and organic molecules, etc.

 

What is the Function of Mitochondria? 

The most common function of Mitochondria is energy generation. However, it performs several other vital functions of the body. These include the following.


Mitochondria Functions


Mitochondria Functions


Energy Generation

Mitochondria help produce ATP molecules which are the energy units of cells. Most energy production takes place in the cristae or folds of the inner membrane. It generates energy by converting chemical energy from food. 


Cell Death

Apoptosis or cell death is an essential part of the regeneration of new cells. As cells damage or become old, they are destroyed by the mitochondria, and new cells are formed. It releases enzymes like Cytochrome C, which helps in cell degeneration. 


Heat Production 

In extreme colds, the body generates its heat by utilising tissue fat. Mitochondria release energy in the form of heat in cold climatic conditions. 


Storing Calcium 

Calcium is involved in several cellular processes. For example, releasing neurotransmitters for nerve conduction and muscle movement, blood clotting, fertilisation, hormone signalling, steroid synthesis, and cellular metabolism. As calcium is so important for the body, cells regulate it tightly. Mitochondria help in the absorption of calcium ions and store them until they are used. 


Some More New Things About Mitochondria

  1. Mitochondria are the powerhouse of cells and produce energy. 

  2. It has a complex structure, and each performs distinct functions. 

  3. Like a nucleus, it has its DNA. 

  4. The outer membrane of the mitochondria has a protein called porins which forms protein channels to facilitate molecule transport.  

  5. Mature red blood cells have no mitochondria. 

  6. Liver cells have more than 2,000 mitochondria. 

  7. It has dividing and multiplying abilities. 

  8. In human sperm, mitochondria are spiral-shaped and provide energy for motion. 


Summary

Mitochondria are popularly known for their ability to generate energy. They are a double membrane organelle and have a typical structure and are called the powerhouse of a cell. They carry numerous bodily functions and metabolic activities, including heat generation, apoptosis, neurotransmitter regulation, calcium uptake, etc. Interestingly, they have their DNA while other cell organelles do not possess DNA.


Changes in the mitochondrial DNA can lead to insufficient ATP or energy production and other critical diseases. The number of mitochondria varies from cell to cell or organism to organism. For example, human liver cells have more than 2000 mitochondria, whereas human red blood cells have no mitochondria. In the end, we have seen some facts about mitochondria. If there are any doubts related to the topic please ask in the comments.

FAQs on Mitochondria

1. What are mitochondrial diseases?

The DNA within mitochondria is more susceptible to damage because some substances are produced during ATP production that harms the DNA. However, mitochondrial diseases occur due to changes in the DNA. This organelle also lacks protective mechanisms. Improper functioning of mitochondria results in severe health conditions. These include:

  • Bipolar disorder

  • Alzheimer's disease

  • Parkinson's disease

  • Diabetes

  • Autism

  • Huntington's disease

  • Chronic fatigue syndrome

  • Schizophrenia

The symptoms of mitochondrial diseases vary depending upon the type of cell. Some of the symptoms include weakness, kidney disease, liver disease, dementia, learning disabilities, etc.

2. How many mitochondria does the cell have?

Mitochondria require nuclear genes and mitochondrial products for their formation. These organelles then replicate by dividing in two. The organelle is present in both plants and animals. The number of mitochondria varies from cell to cell. The amount of this organelle depends on the need for energy and the functions they perform. Liver cells can have 1000 to 2000 mitochondria per cell, while heart muscle contains nearly 5000 mitochondria per cell. Hence, the number of mitochondria ranges from 100,000 to 600,000 in each cell.

3. Which organ contains the highest number of mitochondria?

The heart contains the highest number of mitochondria. There are about 5,000 mitochondria per cell in heart muscle cells.