The production of energy by oxidative phosphorylation is mitochondria’s most significant job. Let us understand further.
The traditional function of mitochondria in a cell is to carry out cellular respiration. They can also store calcium, which helps to keep the homeostasis of the cell’s calcium levels. Additionally, they control the metabolism of the cell and participate in apoptosis, cell signalling, and thermogenesis.
In a process known as binary fission, mitochondria copy their DNA, allowing them to create several copies of the same piece of DNA within a single mitochondrion.
Structure of mitochondria.
Mitochondria is a double membrane bound organelle. It is divided up into multiple compartments, each with a different function. The key regions include some of the following:
- Outer membrane
- Intermembrane space
- Inner membrane
- Mitochondrial DNA
The outer membrane easily permits the passage of small molecules. Porins, a class of proteins found in this outer layer, provide channels through which other proteins can pass. A large number of enzymes with a diverse range of functions are also present in the outer membrane.
This space is positioned between the inner and outer membranes.Proteins that are essential for mitochondrial energetics and apoptosis are stored in the intermembrane space.
Proteins with many functions are stored in the inner membrane. The absence of porins in the inner membrane renders it impermeable to the majority of molecules. Only particular membrane transporters are able to transport molecules through the inner membrane. The inner membrane is where the majority of ATP is made.
A fold in the mitochondrion’s inner membrane is called a cristae. Cristae provides a significant amount of surface area for chemical reactions to take place on and gives the inner membrane its distinctive wrinkled structure.
The interior of the inner membrane is called the matrix. Mitochondrial matrix have lots of functions. The TCA cycle, a crucial step in the creation of energy, takes place here. Apart from this, it is where mitochondrial DNA is stored.
Mitochondria also have their own DNA and it has specific uniparental inheritance. Mitochondrial DNA (mtDNA) has numerous unique characteristics, including a high copy number per cell, maternal inheritance, and a high mutation rate, which have drawn the attention of researchers in a variety of domains.
Composition of mitochondria:
Mitochondrial membrane consists of the phospholipids and proteins that make up the plasma membrane. Let us understand the composition of mitochondria in detail.
Mitochondria contain two surfaces with protein and a bimolecular lipid layer in between the surface. The outer surface contain high level of phosphatidyl inositol and cholesterol while the inner surface have high level of cardiolipin.
It contains a circular DNA and several ribosomes. In addition, it has enzymes for the respiratory chain, lipid and amino metabolism, citric acid cycle, and protein synthesis.
Where is mitochondria located?
Mitochondria is the organelle where the cellular respiration takes place and the energy is produced. Let us explore in details the location of mitochondria.
Mitochondria is located in the cytoplasm of all eukaryotic cell. All bodily cells, with the exception of a few, includes mitochondria. Depending on the cell type and function, several mitochondria are typically found in a single cell.
List of important functions of mitochondria:
Mitochondria has several important functions. Let us see some of the major functions of mitochondria below.
- Production of ATP
- Calcium Homeostasis
- Regulation of Innate Immunity
- Programmed Cell Death
- Stem Cell Regulation
Production of ATP:
The majority of the adenosine triphosphate (ATP) generated during glucose metabolism is produced by the mitochondria through oxidative phosphorylation. The proton gradient from across the inner membrane of mitochondria, which is created by mitochondrial respiration, powers this complex system.
The movement of calcium into and out of a cell’s mitochondria is known as mitochondrial calcium exchange, and is crucial for controlling metabolism. A study that was published in April 2017 in the journal Nature found that calcium efflux from mitochondria is essential for heart health.
The creation of energy for cellular function involves calcium. The concentration of calcium rises when buffering and structuring the cytosol as well as when controlling cell destiny by inducing or inhibiting apoptosis.
Regulation of Innate Immunity:
An essential part of the mammalian immune response is played by the innate immune system. Recent studies have shown that innate immunity pathways involving TLR9, NLRP3, and STING signalling are activated by mitochondrial DNA, contributing to the signalling platforms and producing effector responses.
Programmed Cell Death
The process by which mitochondria control the activation of caspases and program cell death is known as mitochondrial outer membrane permeabilization (MOMP), which results in the release of a large number of proteins into the intermembrane gap that trigger program cell death.
Stem Cell Regulation:
Reactive oxygen species (ROS), which are produced by mitochondria, have been demonstrated to control somatic stem cell fate. An increase in ROS is linked to a decline in the ability of human mesenchymal stem cells to regenerate and a shift toward progenitor commitment and differentiation.
In the development, reprogramming, and maintenance of induced pluripotent stem cells’ pluripotency, mitochondria are thought to be essential
These few examples only scratch the surface of the powerful impact that mitochondria can have on cell health and function. As these nuances and the mechanisms underlying mitochondrial malfunction continue to be understood, new and better treatments for a variety of diseases should emerge.