What Are Mitochondria? Definition, Function & Structure

Mitochondria – Definition, Discovery, Importance and Function

What Are Mitochondria? Definition, Function & Structure

Mitochondria which is wise known as the powerhouses of the cell is subcellular, cylindrical organelles located in eukaryotes.

They have a major impact on body metabolism in people with autism and additionally play a role in each individual’s wellbeing as far as how our body produces energy.

Every living organism is created witha central brick which is the cell and the number of mitochondria in each cellcould broadly change by tissue, organism, and cell type.

Mitochondria areorganelles located in the cells of each complex organism. These organelles are shapedin a rod- structure located in both plant and animal cells, and they createaround 90% of the chemical energy which cells need in order to survive.

Although they do not just produce energy, they producechemicals as well that the body system requires for different purposes such as breakingdown wastes so that they would be less harmful, and also recycle some of thewastes to save energy.

It is composed of:

  • The Outer membrane
  • The Inner membrane
  • The Intermembrane space
  • The Cristae
  • TheMatrix

Function in a Cell

The primary function is the creation of ATP via cellular respiration. The mitochondria pick the nutrientsof a cell and move them into energy through the form ATP. The higher energy acell needs increases the number of mitochondria it would have. If a cell needsmore energy than what is left, it can make more as required.

Otherfunctions include:

  1. Proteolyticactivity: Mitochondria haveproteolytic enzyme activity. Even in Protozoa, it exhibits both lytic and syntheticactivity. In Amoeba, pieces of immersed food circulate in the cytoplasm andlater they get related to mitochondria. This then shows that they arein charge of the creation of zymogen granules of the pancreas.
  2. Assist in safeguardingcell survival at the same time convenient to assist the progress of apoptosiswhen essential.
  3. It addsto breaking-down, synthesizing, and recycling bio-chemicals required for cellfunctioning.

Mitochondriaare self-reproducing organelles. Reproduction happens, responding tophysiological necessities.

They contain DNA, ribosomes and essential enzymes tomaintain protein synthesis and synthesis of phospholipids as well as otherlittle molecular weight constituents. 


The mitochondria are themain areas of your muscle cells where fat, carbohydrate, and protein could bebroken down with oxygen to produce the energy needed to work.

They areessential for ocular function, representing the significant origin of a cell'ssupply of energy and as well taking up an important role in cell survival anddifferentiation.

They are not only vital in that aspect, but also in otherswhich include:

  1. They are important for your lifespan: Are important fora lot of biological processes, so it is analytical that their extremedysfunction is identified with untimely aging and death.
  2. Essential for fat loss: More mitochondria produce moreenergy from amino acids, glucose, and fat and because of this, consume morecalories.
  3. An important factor to enhance yourathletic performance: Thehighest limit to how quick you could run a specific distance, or whatever otherphysical exercises that needs perseverance, is the time it takes to createenergy from oxygen and sugar in your exercising muscles. Acquiring more in your muscle cells would enhance their energy generation and with this, itboosts performance.
  4. Assists in maintaining your bloodsugar levels: Accordingto research, patients with type 2 diabetes have a diminished mitochondrialnumber, capacity, and biogenesis. In insulin creation, which happens in yourpancreatic beta cells, assuming an essential role in maintaining theblood sugar levels.
  5. Perfectly working mitochondria avert heart disease: help in the regulation of cardiovascular cellfunction, an on the other side, mitochondrial dysfunction increases the dangerof cardiovascular illness.

The Discovery of Mitochondria

Mitochondria were named by CarlBenda in 1898 from his study of cell internal structure and the first recorded information of mitochondria in plants incells was created by Friedrich Meves in 1904.

In 1908, Friedrich Meves andClaudius Regaud showed that they contain lipids and proteins. However, thereare two speculations about the its discovery: autogenous andendosymbiotic.

In theautogenous hypothesis, mitochondria were formed by separating a part of DNAfrom the nucleus of the eukaryotic cell at the period of branching out with theprokaryotes; this DNA segment would have been confined by membranes, thatcouldn’t be crossed by proteins.

The endosymbiotic shows that mitochondria wereinitially prokaryotic cells, perfect for executing oxidative components thatwere unrealistic for eukaryotic cells; they developed into endosymbionts residingin the eukaryote. Since mitochondria have a lot of characteristics similar tobacteria, the endosymbiotic hypothesis is generally accepted.

A majorreason it is believed that mitochondria originated from bacteria is thatdespite everything, they contain a little amount of DNA which is bacterialDNA and the mitochondrial DNA is around 16,000 bases in length and has 37 genesin individuals.

The Mitochondria's Job

Its primary job is to turn glucose into energy via cellular or aerobic respiration utilizing oxygen and water. This takes place when food is broken down into the smallest nutrients and molecules, and the air is taken in, the least molecules and nutrients move into the bloodstream.

These nutrients and molecules consist of glucose and oxygen. Since fire burns oxygen and emits water and carbon dioxide, mitochondria act heaters when they turn glucose into adenosine triphosphate (ATP), they utilize oxygen and give off water and carbon dioxide.

Since the procedure utilizes oxygen, it is known to be aerobic. This chemical procedure of respiration happens in each cell, so it is known as aerobic cellular respiration. The steps that take place in this procedure are shown by the Krebs cycle or the tricarboxylic acid [TCA] cycle, and it is a foundation to knowing how cells function.

However, in plants, mitochondria work alongside chloroplasts to control ecological factors and make the genetic material. They work separately to produce functional energy for natural activity, alongside chloroplasts operating photosynthesis carrying out the final three stages of cellular respiration.

Microscopy's Role

The performance of the microscope in studying cells was a progress in technology. The microscope enabled the viewing of a cell the blue with a person’s eye. The light addition to the microscope created by Hooke enables the cell to be considerably more visible for additional study.

Not only that, the microscope plays other roles which are:

  • Introducing electron microscope and dyes took the study of cells much further. These innovations enabled scientists to differentiate one section of the cell from another. Scientists can not only see any imperfection or damage to the cell; they could also recognize the correct area inside the cell that was harmed or faulty.
  • Viewing organisms, both multi-cellular and unicellular. With the utilization of microscope, it is possible to see cells carry out their various activities, and also reproduce.
  • The microscope has improved the study of cells by enabling scientists to view the development of disease inside a cell. Once they could see the development of diseases, for example, cancer, he or she could endeavor to treat the cell. Making use of a microscope enables the scientist to study and evaluate the treatment and decide whether the treatment is successful.

Read about Organelles and their Functions here

Also:  Nucleus, Ribosomes, Golgi Apparatus, Lysosomes

Return to Eukaryotes and Prokaryotes

Return to Cell Biology and Cell Staining

Return from Mitochondria to MicroscopeMaster Home

Source: https://www.microscopemaster.com/mitochondria.html

Mitochondria – Structure And Functions

What Are Mitochondria? Definition, Function & Structure

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Mitochondria are bacteria-sized organelles (about 1 × 2 μm in size), which are found in large numbers in almost all eukaryotic cells. Typically, there are about 2000 mitochondria per cell, representing around 25% of the cell volume.

Structure of Mitochondria

  • Mitochondria are enclosed by two membranes—a smooth outer membrane and a markedly folded or tubular inner mitochondrial membrane, which has a large surface and encloses the matrix space.
  • The folds of the inner membrane are known as cristae, and tube- protrusions are called tubules.
  • The intermembrane space is located between the inner and the outer membranes.
  • The number and shape of the mitochondria, as well as the numbers of cristae they have, can differ widely from cell type to cell type.
  • Tissues with intensive oxidative metabolism— e. g., heart muscle—have mitochondria with particularly large numbers of cristae.
  • Even within one type of tissue, the shape of the mitochondria can vary depending on their functional status.
  • Mitochondria are mobile, plastic organelles.
  • Mitochondria probably developed during an early phase of evolution from aerobic bacteria that entered into symbiosis with primeval anaerobic eukaryotes.
  • This endo-symbiont theory is supported by many findings. For example, mitochondria have a ringshaped DNA (four molecules per mitochondrion) and have their own ribosomes. The mitochondrial genome became smaller and smaller during the course of evolution.
  • In humans, it still contains 16,569 base pairs, which code for two rRNAs, 22 tRNAs, and 13 proteins.
  • Only these 13 proteins (mostly subunits of respiratory chain complexes) are produced in the mitochondrion.
  •  The mitochondrial envelope consisting of two membranes also supports the endosymbiont theory.
  • The inner membrane, derived from the former symbiont, has a structure reminiscent of prokaryotes.
  • It contains the unusual lipid cardiolipin, but hardly any cholesterol.
  • Both mitochondrial membranes are very rich in proteins.
  • Porins in the outer membrane allow small molecules to be exchanged between the cytoplasm and the intermembrane space.
  • The inner mitochondrial membrane is completely impermeable even to small molecules (with the exception of O2, CO2, and H2O).
  • Numerous transporters in the inner membrane ensure the import and export of important metabolites.
  • The inner membrane also transports respiratory chain complexes, ATP synthase, and other enzymes.
  • The matrix is also rich in enzymes.

Functions of Mitochondria

  1. The most important function of the mitochondria is to produce energy.
  2. The simpler molecules of nutrition are sent to the mitochondria to be processed and to produce charged molecules.
  3. These charged molecules combine with oxygen and produce ATP molecules. This process is known as oxidative phosphorylation.
  4. Mitochondria help the cells to maintain proper concentration of calcium ions within the compartments of the cell.
  5. The mitochondria also help in building certain parts of blood and hormones testosterone and estrogen.
  6. The liver cells mitochondria have enzymes that detoxify ammonia.
  7. The mitochondria also play important role in the process of apoptosis or programmed cell death.
  8. Abnormal death of cells due to the dysfunction of mitochondria can affect the function of organ. 

Source: https://alevelbiology.co.uk/notes/mitochondria-structure-and-functions/

What Is Mitochondria (Structure, Diagram & Function)

What Are Mitochondria? Definition, Function & Structure

“Mitochondria are membrane-bound organelles present in the cytoplasm of all eukaryotic cells, that produces adinosine triphosphate (ATP), the main energy molecule used by the cell.”

Table of Contents

  • Explanation
  • Diagram
  • Structure
  • Function
  • Disorders

Read on to explore what is mitochondria, its structure, and functions.

What is Mitochondria?

Popularly known as the “Powerhouse of the cell,” mitochondria (singular: mitochondrion) are a double-membrane-bound organelle found in most eukaryotic organisms. They are found inside the cytoplasm and essentially functions as the cell’s “digestive system.”

They play a major role in breaking down nutrients and generating energy-rich molecules for the cell. Many of the biochemical reactions involved in cellular respiration take place within the mitochondria.

The term ‘mitochondrion’ is derived from the Greek words “mitos” and “chondrion” which means “thread” and “granules-” respectively.

It was first described by a German pathologist named Richard Altmann in the year 1890.

Also refer: Cell Organelles 

Mitochondria Diagram

The diagram of mitochondria below illustrates several structural features of mitochondria.

Mitochondria diagram explaining the structure of mitochondria

Structure of Mitochondria

  • The mitochondrion is a double-membraned, rod-shaped structure found in both plant and animal cell.
  • Its size ranges from 0.5 to 1.0 micrometre in diameter.
  • The structure comprises an outer membrane, an inner membrane, and a gel- material called the matrix.
  • The outer membrane and the inner membrane are made of proteins and phospholipid layers separated by the intermembrane space.
  • The outer membrane covers the surface of the mitochondrion and has a large number of special proteins known as porins.
  • It is freely permeable to ions, nutrient molecules, energy molecules the ADP and ATP molecules.

The inner membrane of mitochondria is rather complex in structure. It has many folds that form a layered structure called cristae, and this helps in increasing the surface area inside the organelle. The cristae and the proteins of the inner membrane aids in the production of ATP molecules.

The inner membrane is strictly permeable only to oxygen and to ATP molecules. A number of chemical reactions take place within the inner membrane of mitochondria.

Mitochondrial Matrix

The mitochondrial matrix is a viscous fluid that contains a mixture of enzymes and proteins. It also comprises ribosomes, inorganic ions, mitochondrial DNA, nucleotide cofactors, and organic molecules. The enzymes present in the matrix play an important role in the synthesis of ATP molecules.

Also Read: Difference between mitochondria and plastids

Function of Mitochondria

The most important function of mitochondria is to produce energy through the process of oxidative phosphorylation. It is also involved in the following process:

  1. Regulates the metabolic activity of the cell
  2. Promotes the growth of new cells and cell multiplication
  3. Helps in detoxifying ammonia in the liver cells
  4. Plays an important role in apoptosis or programmed cell death
  5. Responsible for building certain parts of the blood and various hormones testosterone and oestrogen
  6. Helps in maintaining an adequate concentration of calcium ions within the compartments of the cell
  7. It is also involved in various cellular activities cellular differentiation, cell signalling, cell senescence, controlling the cell cycle and also in cell growth.

Disorders Associated With Mitochondria

Any irregularity in the way mitochondria functions can directly affect human health, but often, it is difficult to identify because symptoms differ from person to person. Disorders of the mitochondria can be quite severe; in some cases, it can even cause an organ to fail.

Mitochondrial diseases: Alpers Disease, Barth Syndrome, Kearns-Sayre syndrome (KSS)

Also Read: Eukaryotic Cells

Mitochondria is a membrane-bound organelle present in the cytoplasm of all eukaryotic cells. It is responsible for producing Adenosine triphosphate (ATP), the main energy currency of the cell.

Mitochondria is the cell organelles that are responsible for producing ATP, the energy currency of the cell.

Mitochondria is a rod-shaped, double membraned organelle. It is found both in plant cells and animal cells.

The inner membrane of mitochondria has many folds. These folds form a layered structure called cristae.

A mitochondrial matrix is a viscous fluid containing a mixture of enzymes, ribosomes, inorganic ions, mitochondrial DNA, nucleotide cofactors, and organic molecules.

Mitochondria’s primary function is to produce energy through the process of oxidative phosphorylation. Besides this, it is responsible for regulating the metabolic activity of the cell. It also promotes cell multiplication and cell growth. Mitochondria also detoxes ammonia in the liver cells. Moreover, it plays an important role in apoptosis or programmed cell death.

Alpers disease, Barth syndrome, Kearns-Sayre syndrome.

To know more about what is mitochondria, its structure, function, and mitochondria diagram, keep visiting BYJU’S website or download BYJU’S app for further reference.

Source: https://byjus.com/biology/mitochondria/


What Are Mitochondria? Definition, Function & Structure

Mitochondria (singular: mitochondrion) are organelles within eukaryotic cells that produce adenosine triphosphate (ATP), the main energy molecule used by the cell.

For this reason, the mitochondrion is sometimes referred to as “the powerhouse of the cell”. Mitochondria are found in all eukaryotes, which are all living things that are not bacteria or archaea.

It is thought that mitochondria arose from once free-living bacteria that were incorporated into cells.

Mitochondria produce ATP through process of cellular respiration—specifically, aerobic respiration, which requires oxygen. The citric acid cycle, or Krebs cycle, takes place in the mitochondria. This cycle involves the oxidation of pyruvate, which comes from glucose, to form the molecule acetyl-CoA. Acetyl-CoA is in turn oxidized and ATP is produced.

The citric acid cycle reduces nicotinamide adenine dinucleotide (NAD+) to NADH. NADH is then used in the process of oxidative phosphorylation, which also takes place in the mitochondria.

Electrons from NADH travel through protein complexes that are embedded in the inner membrane of the mitochondria. This set of proteins is called an electron transport chain.

Energy from the electron transport chain is then used to transport proteins back across the membrane, which power ATP synthase to form ATP.

The amount of mitochondria in a cell depends on how much energy that cell needs to produce. Muscle cells, for example, have many mitochondria because they need to produce energy to move the body.

Red blood cells, which carry oxygen to other cells, have none; they do not need to produce energy.

Mitochondria are analogous to a furnace or a powerhouse in the cell because, furnaces and powerhouses, mitochondria produce energy from basic components (in this case, molecules that have been broken down so that they can be used).

Mitochondria have many other functions as well. They can store calcium, which maintains homeostasis of calcium levels in the cell. They also regulate the cell’s metabolism and have roles in apoptosis (controlled cell death), cell signaling, and thermogenesis (heat production).

Mitochondria have two membranes, an outer membrane and an inner membrane. These membranes are made of phospholipid layers, just the cell’s outer membrane.

The outer membrane covers the surface of the mitochondrion, while the inner membrane is located within and has many folds called cristae.

The folds increase surface area of the membrane, which is important because the inner membrane holds the proteins involved in the electron transport chain. It is also where many other chemical reactions take place to carry out the mitochondria’s many functions.

An increased surface area creates more space for more reactions to occur, and increases the mitochondria’s output. The space between the outer and inner membranes is called the intermembrane space, and the space inside the inner membrane is called the matrix.

This diagram shows the structure of a mitochondrion.

Mitochondria are thought to have evolved from free-living bacteria that developed into a symbiotic relationship with a prokaryotic cell, providing it energy in return for a safe place to live.

It eventually became an organelle, a specialized structure within the cell, the presence of which are used to distinguish eukaryotic cells from prokaryotic cells.

This occurred over a long process of millions of years, and now the mitochondria inside the cell cannot live separately from it. The idea that mitochondria evolved this way is called endosymbiotic theory.

Endosymbiotic theory has multiple forms of evidence. For example, mitochondria have their own DNA that is separate from the DNA in the cell’s nucleus. It is called mitochondrial DNA or mtDNA, and it is only passed down through females because sperm do not have mitochondria.

You received your mtDNA from your mother, and you can only pass it on if you are a female who has a child. It is also circular, bacterial DNA. Another form of evidence is the way new mitochondria are created in the cell.

New mitochondria only arise from binary fission, or splitting, which is the same way that bacteria asexually reproduce. If all of the mitochondria are removed from a cell, it can’t make new ones because there are no existing mitochondria there to split.

Also, the genome of mitochondria and Rickettsia bacteria (bacteria that can cause spotted fever and typhus) have been compared, and the sequence is so similar that it suggests that mitochondria are closely related to Rickettsia.

Chloroplasts, the organelles in plants where photosynthesis occurs, are also thought to have evolved from endosymbiotic bacteria for similar reasons: they have separate, circular DNA, a double membrane structure, and split through binary fission.

1. Which is a function of mitochondria?
A. Regulating metabolism
B. Producing ATP
C. Storing calcium
D. All of the above

D is correct. All of the above are functions of mitochondria. Mitochondria also have roles in apoptosis, cell signaling, and thermogenesis.

2. Which is NOT a reason why mitochondria are thought to have evolved from free-living bacteria?
A. Mitochondria have their own DNA.
B. Mitochondria reproduce through binary fission.
C. Mitochondrial DNA is inherited matrilineally.
D. The genome is similar to that of bacterial DNA.

C is correct. While it is true that mtDNA is inherited from the mother, it is not a reason why mitochondria are thought to have evolved from bacteria that had an endosymbiotic relationship with cells. It is inherited this way because sperm do not contain mitochondria. Choices A, B, and D suggest that mitochondria have similarities to, and evolved from, bacteria.

3. Where is the mitochondrial matrix located?
A. Within the inner membrane
B. Between the inner and outer membrane
C. Inside the mtDNA
D. In the intermembrane space

A is correct. The matrix is a space enclosed by the mitochondrion’s inner membrane. Choices B and D both refer to the intermembrane space, which is the space between the two membranes.

Source: https://biologydictionary.net/mitochondria/

Mitochondria: Definition, Structure & Function (with Diagram)

What Are Mitochondria? Definition, Function & Structure

The eukaryotic cells of living organisms continuously carry out a huge number of chemical reactions to live, grow, reproduce and fight off disease.

All these processes require energy at the cellular level. Each cell that engages in any of these activities gets its energy from the mitochondria, tiny organelles that act as the cells' powerhouses. The singular of mitochondria is mitochondrion.

In humans, cells such as red blood corpuscles don't have these tiny organelles, but most other cells have large numbers of mitochondria. Muscle cells, for example, may have hundreds or even thousands to satisfy their energy requirements.

Almost every living thing that moves, grows or thinks has mitochondria in the background, producing the necessary chemical energy.

Mitochondria are membrane-bound organelles enclosed by a double membrane.

They have a smooth outer membrane enclosing the organelle and a folded inner membrane. The folds of the inner membrane are called cristae, the singular of which is crista, and the folds are where the reactions creating mitochondrial energy take place.

The inner membrane contains a fluid called the matrix while the intermembrane space located between the two membranes is also filled with fluid.

Because of this relatively simple cell structure, mitochondria have only two separate operating volumes: the matrix inside the inner membrane and the intermembrane space. They rely on transfers between the two volumes for energy generation.

To increase efficiency and maximize energy creation potential, the inner membrane folds penetrate deep into the matrix.

As a result, the inner membrane has a large surface area, and no part of the matrix is far from an inner membrane fold. The folds and large surface area help with the mitochondrial function, increasing the potential rate of transfer between the matrix and the intermembrane space across the inner membrane.

While single cells originally evolved without mitochondria or other membrane-bound organelles, complex multicellular organisms and warm-blooded animals such as mammals get their energy from cellular respiration the mitochondrial function.

High-energy functions such as those of the heart muscles or bird wings have high concentrations of mitochondria that supply the energy needed.

Through their ATP synthesis function, mitochondria in muscles and other cells produce the body heat to keep warm-blooded animals at a steady temperature. It is this concentrated energy production capability of mitochondria that makes the high-energy activities and the production of heat in higher animals possible.

The energy-production cycle in mitochondria relies on the an electron transport chain along with the citric acid or Krebs cycle.
Read more about the Krebs Cycle.

The process of breaking down carbohydrates such as glucose to make ATP is called catabolism. The electrons from glucose oxidation are passed along a chemical reaction chain that includes the citric acid cycle.

Energy from the reduction-oxidation, or redox, reactions is used to transfer protons the matrix where the reactions are taking place. The final reaction in the mitochondrial function chain is one in which oxygen from cellular respiration undergoes reduction to form water. The end products of the reactions are water and ATP.

The key enzymes responsible for mitochondrial energy production are nicotinamide adenine dinucleotide phosphate (NADP), nicotinamide adenine dinucleotide (NAD), adenosine diphosphate (ADP) and flavin adenine dinucleotide (FAD).

They work together to help transfer protons from hydrogen molecules in the matrix across the inner mitochondrial membrane.

This creates a chemical and electrical potential across the membrane with the protons returning to the matrix through the enzyme ATP synthase, resulting in the phosphorylation and production of adenosine triphosphate (ATP).
Read about the structure and function of ATP.

ATP synthesis and the ATP molecules are the prime carriers of energy in cells and can be used by the cells for the production of the chemicals necessary for living organisms.

••• Sciencing

In addition to being energy producers, mitochondria can help with cell-to-cell signaling through the release of calcium.

Mitochondria have the ability to store calcium in the matrix and can release it when certain enzymes or hormones are present. As a result, cells producing such triggering chemicals may see the signal of rising calcium from the release by the mitochondria.

Overall, mitochondria are a vital component of living cells, helping with cell interactions, distributing complex chemicals and producing the ATP that forms the energy basis for all life.

The mitochondrial double membrane has different functions for the inner and outer membrane and the two membranes and are made up of different substances.

The outer mitochondrial membrane encloses the fluid of the intermembrane space, but it has to allow chemicals that the mitochondria need to pass through it. Energy-storage molecules produced by the mitochondria have to be able to leave the organelle and deliver energy to the rest of the cell.

To allow for such transfers, the outer membrane is made up of phospholipids and protein structures called porins that leave tiny holes or pores in the surface of the membrane.

The intermembrane space contains fluid that has a composition similar to that of the cytosol making up the fluid of the surrounding cell.

Small molecules, ions, nutrients and the energy-carrying ATP molecule produced by ATP synthesis can penetrate the outer membrane and transition between the fluid of the intermembrane space and the cytosol..

The inner membrane has a complex structure with enzymes, proteins and fats allowing only water, carbon dioxide and oxygen to pass through the membrane freely.

Other molecules, including large proteins, can penetrate the membrane but only through special transport proteins that limit their passage. The large surface area of the inner membrane, resulting from the cristae folds, provides room for all these complex protein and chemical structures.

Their large number permits a high level of chemical activity and an efficient production of energy.

The process by which energy is produced through chemical transfers across the inner membrane is called oxidative phosphorylation.

During this process, the oxidation of carbohydrates in the mitochondria pumps protons across the inner membrane from the matrix into the intermembrane space. The imbalance in protons causes the protons to diffuse back across the inner membrane into the matrix through an enzyme complex that is a precursor form of ATP and is called ATP synthase.

The flow of protons through ATP synthase in turn is the basis for ATP synthesis and it produces ATP molecules, the main energy-storage mechanism in cells.

The viscous fluid inside the inner membrane is called the matrix.

It interacts with the inner membrane to carry out the main energy-producing functions of the mitochondria. It contains the enzymes and chemicals that take part in the krebs cycle to produce ATP from glucose and fatty acids.

The matrix is where the mitochondrial genome made up of circular DNA is found and where the ribosomes are located. The presence of ribosomes and DNA means that the mitochondria can produce their own proteins and can reproduce using their own DNA, without relying on cell division.

If mitochondria seem to be tiny, complete cells on their own, it is because they were probably separate cells at one point when single cells were still evolving.

Mitochondrion- bacteria entered larger cells as parasites and were allowed to remain because the arrangement was mutually beneficial.

The bacteria were able to reproduce in a secure environment and supplied energy to the larger cell. Over hundreds of millions of years, the bacteria became integrated into multicellular organisms and evolved into today's mitochondria.

Because they are found in animal cells today, they form a key part of early human evolution.

Since mitochondria multiply independently the mitochondrial genome and don't take part in cell division, new cells simply inherit the mitochondria that happen to be in their part of the cytosol when the cell divides.

This function is important for the reproduction of higher organisms, including humans, because embryos develop from a fertilized egg.

The egg cell from the mother is large and contains a lot of mitochondria in its cytosol while the fertilizing sperm cell from the father has hardly any. As a result, children inherit their mitochondria and their mitochondrial DNA from their mother.

Through their ATP synthesis function in the matrix and through cellular respiration across the double membrane, mitochondria and the mitochondrial function are a key component of animal cells and help make life as it exists possible.

Cell structure with membrane-bound organelles has played an important part in human evolution and mitochondria have made an essential contribution.

Source: https://sciencing.com/mitochondria-definition-structure-function-with-diagram-13717287.html

The Structure and Function of Mitochondria

What Are Mitochondria? Definition, Function & Structure

Edited by Chameleon, SarMal, Jen Moreau

Just you rely on a healthy consumption of caffeine to get moving in the morning, the little cells that make up your body rely on Mitochondria to produce energy. Richard Altman first identified Mitochondria in 1890, labelling the little free floating organelles 'bioblasts.

' This rather insipid term for such a potent part of the cell, was more appropriately coined 'mitochondria' in 1898 by Carl Benda derived from the Greek mito (thread) and kondros (granule), no doubt inspired by the structure of the interior of the mitochondria.

Mitochondria was made famous by Philip Skiekevitz when he fittingly termed it the 'powerhouse of the cell' in 1957. Was this helpful? Yes | No| I need help

The mitochondria (plural mitochondria) is a membrane bound structure found in both eukaryotic plant and animal cells. The primary function of mitochondria is to provide the energy required for various cellular activities, most significantly the formulation of energy. Was this helpful? Yes | No| I need help

Outer Membrane

The outer membrane of mitochondria surrounds the inner membrane, leaving a small space in between called the intermembrane space. The outer membrane has pores large enough to allow ions, molecules and small proteins to pass through. Was this helpful? Yes | No| I need help

Inner Membrane

In contrast to the outer membrane, the inner membrane of mitochondria is much less porous, similar to the plasma membrane of a cell. The inner membrane folds over many times to create layered structures called cristae (singular crista).

The folding of the inner membrane increases the surface area available for biochemical reactions. The shape and number of folds may vary. The inner membrane is full of proteins that aid in the movement of electrons as well as ATP synthesis.

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Production of mtDNA

Located In order to convert chemical energy DNA located inside mitochondria, small organelles within the eukaryotic cells work at converting energy from food into ATP (an energy that cells can utilize).

Although most of the DNA is found in the nucleus, the DNA found in mitochondria (mtDNA) does encode for 37 genes in humans, is inherited from the mother and was a significant portion of the first human genome to be sequenced [1].

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Mitochondria play a significant role in the production of the energy currency of the cell, ATP.

The process of energy production begins in the cytoplasm where glucose is metabolized to produce two 3-carbon molecules called Pyruvate. The conversion of glucose into pyruvate is known as glycolysis. The two pyruvate molecules are then transported into the mitochondria where they are metabolized to form 30 molecules of ATP.

The breakdown of glucose into pyruvate is an aerobic process, which means that it cannot be performed in the absence of oxygen. In addition to pyruvate, mitochondria can also metabolize fatty acids to produce energy molecules.

Apart from energy production, mitochondria also serve the following purposes:Was this helpful? Yes | No| I need help

Production of Heat

Mitochondria are also involved in thermogenesis or production of heat. This process occurs in the mitochondria of cells of brown adipose tissues only. These tissues contain a protein called thermogenin.

Thermogenin plays a role in the transportation of protons into the mitochondrial matrix.Brown adipose tissue or brown fat is found in the human body in small quantities only.

It is found in hibernating animals primarily, such as bears, gray squirrels, and bats. Was this helpful? Yes | No| I need help


Apoptosis is the process of programmed cell death. During apoptosis, a number of cell changes occur, such as shrinkage of the cell, fragmentation of the nuclear structure, condensation of chromatic, etc. Mitochondria play a dual role in apoptosis. They protect the healthy cells while appropriate and facilitate apoptosis when required.

During the process of apoptosis, a special type of protein is produced called proapoptotic proteins. These proteins enter the mitochondrial membrane and form pores in it. As a result, the proteins present within the mitochondria enter the cytosol and initiate a series of biochemical processes that result in the apoptotic death of the cell.

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Storage of Calcium Ions

While bones are the primary storage site of Calcium, at the cellular level, Calcium ions are stored in mitochondria and endoplasmic reticulum. Mitochondria store calcium for a short time only in order to maintain cell homeostasis.Was this helpful? Yes | No| I need help

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MLA (Modern Language Association)“The Structure and Function of Mitochondria.” ScienceAid, scienceaid.net/the_Structure_and_Function_of_Mitochondria Accessed 15 Mar 2020.

Chicago / TurabianScienceAid.net. “The Structure and Function of Mitochondria.” Accessed Mar 15, 2020. https://scienceaid.net/the_Structure_and_Function_of_Mitochondria.


  1. ↑ Anderson, S.; Bankier, A. T.; Barrell, B. G.; de Bruijn, M. H. L.; Coulson, A. R.; Drouin, J.; Eperon, I. C.; Nierlich, D. P.; Roe, B. A.; Sanger, F.; Schreier, P. H.; Smith, A. J. H.; Staden, R.

    ; Young, I. G. (1981). “Sequence and organization of the human mitochondrial genome”. Nature. 290 (5806): 457�”65. Bibcode:1981Natur.290..457A. doi:10.1038/290457a0. PMID 7219534.

Categories : Cell Biology

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