Mitochondria: Structure, Functions, and Location

Cells require energy for survival and proper functioning. Mitochondria is a membrane-bound cell organelle in eukaryotic cells. They are commonly known as the cell’s powerhouse because they supply power (energy) to the cells. 

Mitochondria has its own DNA (deoxyribonucleic acid), and along with the role of energy generator, it also has many other roles like determining cell life, calcium storage, and heat production.  

Structure of Mitochondria

Structure of Mitochondria

Mitochondria are rod or oval-shaped organelles. It is a small cell organelle whose size ranges from 0.75 to 3 µm (similar in size to bacterial cells). Unlike other small cell organelles, a double membrane encloses it. The structural component are as follows:

  • Outer membrane: It is smooth and is made up of porins forming a channel for the movement of proteins. It covers the entire organelle and consists of enzymes carrying many functions.
  • Inter membrane space: It separates the outer membrane and inner membrane.
  • Inner membrane: It is also made up of proteins. It is impermeable to many molecules as there is the absence of porins. However, special membrane transporters help in transferring some molecules. Maximum ATP (adenosine triphosphate) is produced in this layer.
  • Matrix: It is the space inside the inner membrane and the place where DNA lies. It also harbors enzymes that are required in ATP production.
  • Cristae: These are folds in the inner membrane that increase the mitochondria’s surface area for increasing the rate of chemical reactions.
  • DNA: Mitochondria has its own DNA similar to bacterial DNA. Mitochondrial DNA (mtDNA) consists of 17,000 base pairs and holds instructions for synthesizing several proteins. A child receives mtDNA from their mother. 
Structure of mitochondrial DNA
Structure of mitochondrial DNA (mt DNA)

Function of Mitochondria

The functions of mitochondria are as follows:

Energy Production

ATP is the energy currency of the cell. It is a complex chemical compound and is found in almost all organisms. Most of the ATP found in the body is formed here by a series of chemical reactions called Kreb’s cycle. Food consumed breakdowns into energy inside it which is used by the cell. The chemical reaction involved in converting food to energy is called oxidative phosphorylation. 

Storage of Calcium

Calcium is an important component in the human body for various cellular processes like triggering neurotransmission, muscle movement, fertilization, blood clotting, etc. Mitochondria absorb it quickly and store it until they are required.

Heat Production

Mitochondria in brown fat, by the process of protein leak, produce heat. Brown fat is higher in babies, the most susceptible time.

Signaling Cell Death 

Cell death or apoptosis is the natural phenomenon of any cell. Mitochondria signals which cell is damaged and old and needs to be cleared away. It produces cytochrome C, a chief enzyme involved in the destruction of cells during apoptosis.

Location and Number of Mitochondria

It is present in the cytoplasm of the cell. Its number vary in different cells based on the energy produced and required. For example, 40% of the cytoplasm of heart cells is occupied by it since these cells require maximum energy. Similarly, liver cells have the maximum number (2000 per cell), but the mature RBC lacks mitochondria. 

How to Boost Mitochondria?

It plays a crucial role in cells, and human activities affect their functions. There are various things one can do to boost the its functions. They are:

  • Decreasing calories: Consuming more calories leads to obesity and increases the chance of oxidative stress. The stress causes dysfunction in mitochondria. So, consuming few calories to maintain the proper functionality of mitochondria. 
  • Avoid refined carbohydrates: Refined carbs (carbohydrate) like coca-cola, pasta, cereals, etc., can lead to a significant change in the mitochondria of the brain, leading to type 2 diabetes and Alzheimer’s disease. So, avoiding such carbs is best for boosting the mitochondria. 
  • Exercise: Exercise for at least 30 minutes a day can boost the intake of oxygen, which is a vital component for the proper functioning of mitochondria.
  • Sleep: A person should at least sleep for 8 hours for healthy mitochondrial functions.
  • Indulge in relaxation activities: Relaxation activities like meditation, spa, sauna, etc., help reduce the stress of daily life, which is an important cause of degradation of mitochondria in cells. So, meditation, heat therapy (sauna), spa, and massage are very important for boosting mitochondrial activity in today’s world. 
  • Consume 2-3 meals in a day: Consuming a balanced diet at an interval of 8-10 hours at least 2 times a day is another factor increase mitochondrial activity.

Some Facts about Mitochondria

The must-know facts about mitochondria are as follows:

  • They can easily change their shape.
  • They grow bigger if cells require more energy and can die or become inactive when not in use.
  • Since they have their own DNA, which plays a role in synthesizing some proteins.
  • It carries many similarities to bacteria.
  • It can also produce small amounts of carbon dioxide as a by-product of the citric cycle.

References and further reading:

Asma Shrestha

Hello, I am Ashma Shrestha. I am currently pursing my Master's Degree in Microbiology. Passionate about writing and blogging. Key interest in virology and molecular biology

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