Instant Access to A Level Biology Revision

Sign up now to get access to the entire library of A Level Biology resources for all exam boards



The single human body is a universe in itself. Human being is a marvel. There is nothing wrong to say that the human body is the masterpiece of God. Everything is in perfect synchronization and this thing let us marvel at the universe that each and every human being has inside in the forms of cells and organelle. 

Many organelles work in sync to keep the body running at full throttle. Can you imagine life without power? Just as your house runs on power, the body also has a power hub to ready you to brace the everyday challenges. 

Although it is true that everything is made out of cells, but cells cannot work without their perfect organelles. Now is the time to shed light on the powerhouse of cells that is called mitochondria.

Overall Importance of Mitochondria 


Our body’s powerhouses are mitochondria. Mitochondria is a plural term, and its singular variant is the mitochondrion. Although the plural interpretation is widely popular. Not only do mitochondria serve as the human’s powerhouse but also facilitates the animals, plants, and microorganisms equally. The importance of mitochondria could be assessed from the premise that sans mitochondria life would be blackened out. 

This article is to elaborate on mitochondria in a super-easy way. Let us start this fun guide. 

Mitochondria as Powerhouse

You must have been looking into nooks and crannies to find these exquisite bio-charge batteries. Well, mitochondria are not the typical battery-type structures attached to you like a superman. These God-gifted power hubs are lying deep inside the cells. 

The cell is the building block of every sentient being. This is the base level life supporter to us. The cell contains a lot of organelles such as DNA, RNAs (the magical hereditary careers), ribosomes, or mitochondria. 

The mitochondria nestle in the cell. An average body contains zillions of cells, this fact indirectly means that the same number of mitochondria are generating the power to electrify our day in and day out. Without mitochondria things can be very bleak and there is a possibility that life simply cannot exist.

Our whole body contains the cells or in other words mitochondria, but there are few points where mitochondria are found in abundance while in a few places there is scarcity. Let us discuss the mitochondrial distribution. 

  • Technically mitochondria are present in our whole body while in a single cell there can be multiple mitochondria. If the cell requires more energy, there would be multiple mitochondria in a singular cell.
  • Mitochondria are not specific to the animal cells but are equally found in the plant cells as well. You know well that the plants are also sentient beings. They breathe sense and talk but cannot move owing to the grounded roots. Although there is a difference between animal cell and plant cell, but this particular organelle is definitely present in both.
  • Cells that require more energy contain more mitochondria. Just like muscles and heart are the portions where energy is required in abundance. To cater to the thriving energy needs, more mitochondrial batteries are installed in vibrant vital organs. There are probably more mitochondria in your heart for stomach cells then your other organs.
  • Red blood cells or RBCs are the only exceptions, as RBCs do not carry the mitochondria to flow as much blood as they can in one go.

Functions of Mitochondria

As we already know that the mitochondria are the power hubs of any sentient being. Let us delve more into the functions of this power generator. 

Mitochondria are powerhouses of the body

Power generation and storage is the primary function of the mitochondria. These little bodies extend the electrifying vibes to all over the body. The power is generated by the breaking down of glucose (extracted from the food intake). This power is then stored by the mitochondria and sends on requisition by any organ. 

Ever wondered why human organs manage to work 24/7 without any visible form of electrifying energy? Human body works fine because of the presence of mitochondria that is within the cells.

Mitochondria produce ATP

ATP is the energy currency of the cell. These are the energy bundles required to perform the daily vital functions of the body. ATP compromises the quick energy packet to send power throughout the body. ATP is the chemical energy that then converts into different forms. The body gets the required ATP energy because of the presence of mitochondria. these powerhouses of cells workday and night to provide our body with these energy bundles.

Mitochondria also spur the metabolic reaction

The metabolic reaction is just like the pantry of our body. The kitchen where the food is produced. The kitchen stove also needs the fire, and this fire is provided by the mitochondria. Probably it is right to say that without mitochondria metabolism cannot happen.

Metabolic reaction breaks down the ingested food into granular pieces to make glucose and the energy required in this complex conversion is sponsored by mitochondria. 

The powerhouse programs cell death

Yes, mitochondria call the death spell for the cell. When a cell completes its natural living cycle then mitochondria cuts down the power supply and the cell shut down gradually. This sequenced process is aptly managed by the mitochondria. This may sound a bit eerie but the cells in our body reach their final stage. Once it is time for a cell to say goodbye mitochondria cutbacks the power supply and let the cell die in peace.

Mitochondria regulate cell operations

Although mitochondria do not hold a business degree from the ivory league. This little powerhouse is a shrewd manager. Mitochondria regulate the supply line and drip feed the required power to the cell. More in excruciating times and less in resting times such as sleep cycle. Your body the function works properly throughout the day and night because of mitochondria. Without this brilliant organelle, life is simply a living hell.

Discovery of Mitochondria

Mitochondria are the powerhouses of the cell and are firstly discovered by scientist Alber Von Kolliker. The same scientist is considered as the founding father of the mitochondria. This initial discovery has further elaborations by following scientists such as Richard Altman who named the discovery as bioblasts in 1886. Finally, the in-vogue pseudonym is coined by Carl Banda who named these little charges as mitochondria.

Structure of Mitochondria

Just like a battery has different extraneous parts that work in sync and generate power vibes. Mitochondria are not isolated structures but contain minor organelles to work superbly. Let us discuss each one in detail. 

Dual membrane

Mitochondria are protected by a dial layering; inner and outer membranes. As we secure the invaluable assets in the double lock, in the same way, nature has done the dual lock protection for the mitochondria. Dual membrane gives resilience to the mitochondria and mitochondria keeps doing the work in testing or resting times equally. 


The floating ribosomes inside a mitochondrion are the protein synthesizers. Protein is just like a greasy oil to run the fuel lamps of the mitochondrion. Ribosomes are the heart of mitochondrial function. We can put it this way. Our bodily functions take the required energy from mitochondria, and mitochondria takes the energy from ribosomes. 

DNA acid

Deoxyribonucleic or DNA acid is a chain of two hereditary chronicle threads interweaved together. This exquisite structure helps in the maintenance, functioning, and development of the cell. 


Mitochondrial granules possess the calcium, lipid, and phospholipids to speed up the enzymatic function of the cell. The granules float between the inner and outer walls of the cell. 


Crista is a fold of the inner membrane to provide a spacious area for enzymatic reactions. This is the surface area of the battleground. Energy produces and shelves in crista. 


Matrix is the sticky jelly present between the membrane curves. The matrix provides agility and firmness to the mitochondrial structure. 

Energy Synthesis

The stepwise procedure of the detailed energy production mechanism is really difficult as it is a fun guide so we will not dive deeper into the nitty-gritty of energy production. The process is defined in an interesting factual form. 

  • As there are two basic items needed to produce the energy; oxygen + fodder. 
  • Mitochondria gets the oxygen from aerobic cellular respiration. 
  • While the fodder is the food we eat. The food is digested into the stomach and is processed as glucose. Mitochondria take leverage of this glucose to run the furnace and use it as cannon fodder. 
  • Carbon dioxide is produced as a by-product. This gas is not required and liability for the cell. The cell processes out the carbon dioxide. Now you may have understood, why do we breathe out carbon dioxide.
  • A fun fact about the mitochondria’s power generation mechanism is that when the cell requires more energy, the mitochondria automatically replaces its copies to generate more energy until it reaches the required scale. So, you can say, when something is troubling with your body, mitochondria works double time to protect the cells inside.
  • Do not stop here another dramatic feature of mitochondria is still on the cards. When the cell does not need energy, the mitochondria die down owing to atrophy. This may seem a little sad. But mitochondria are a loyal partner to the body. Once this organelle feels that the human body does not require it, this dies down so the harmony of the human body is not affected.

Clinical Significance

Mitochondria is a vital cell organelle and in case of any disruption in its functions, besides instant death, the following health complications occur. 

  • Alzheimer’s disease – Alzheimer disease means memory loss and disorientation that can last for days or months.
  • Diabetes – is another dangerous condition where a body cannot process the glucose properly.
  • Cancer – is a very dangerous disease where the human body gets amid abnormal cells. The cancerous, abnormal cells have the potential to eat away the healthy cells and this can lead to a person to die.
  • Muscular dystrophy – if the mitochondria is not functioning properly then this can also lead to muscular dystrophy. This is another dangerous condition where your bones become weaker without any visible cause.
  • Lou Gehrig’s disease – affects the Nerve cells in the brain and spinal cord.

These diseases are to name a few. A simple blip could wipe out the whole virility of the living organism while a prolonged fault could prove fatal for the unfortunate soul. 

History of Mitochondria

Well this just like egg and chicken conundrum, it is believed that the mitochondria have roots as far as the existence of the cell. Popular theory declares mitochondria 1.45 billion years old after examining the fossils of the cell. This is a popular claim up till now, but this can be successfully challenged by another discovery of an older cell fossil. 

The history of the mitochondria is debatable, but one thing is crystal clear that the mitochondria will exist till the last cell exists. Mitochondria is the basic building block of the cell. 

Consequences of Having no Mitochondria

Shut down! Complete blackout! These are the scenes you see when the power supplier of your home is faulted. We, sentient souls, are also charged by a sort of battery and this battery is mitochondria. Sans mitochondria a cell cannot survive and definitely in return we would cease existence. 

Life cannot be imagined without mitochondria batteries. 


We have extensively described the functions, structure, process, and extraneous details of the mitochondria. In summary, we could say that mitochondria are the lifeline of the cell while the latter is the building block of life. These complex power batteries are a natural miracle and cannot be overlooked. Stay charged! 


  1. Denise R. Ferrier, Lippincott Illustrated Reviews, Biochemistry, Ed. 6th
  2. Rodwell, Kennelly, Harper’s Illustrated Biochemistry, Ed. 30th