Mitochondria is one of the important cell organelles present inside a cell.
Every cell has at-least one or more numbers depending on the requirement.
The cells of those organs with high physiological activity posses more number of mitochondria.
Similarly those organelles with low physiological activity have less number of mitochondria.
Further in a typical cell, their location varies within cytoplasm. But in general are more concentrated in the regions of the cell with high physiological activity.
Structure of mitochondria
They can be seen only under an electron microscope.
Their shape differs from being either spherical, club, oval or even thread like structures.
They are divided into two compartments i.e. an inner compartment and an outer compartment.
The inner compartment lies within the inner membrane. The outer compartment is in between outer membrane and inner membrane.
The inner compartment is also called as matrix and is surrounded by inner mitochondrial membrane. This membrane is divided into several folds within which lies the matrix. The membrane also has permeability and hence the substances can move from matrix to fluid in the outer compartment and vice-versa.
The foldings on the inner membrane are termed as cristae which have elementary particles and some enzymes.
The enzymes on cristae and those in matrix are involved in production of energy through breakdown of carbohydrates. Even fats and proteins converted to some form of carbohydrates mitochondria. Even the single stranded DNA lies in the matrix.
The outer compartment is surrounded by outer mitochondrial membrane towards exterior and also by inner mitochondrial membrane towards interiors of mitochondria.
This outer mitochondrial membrane is smooth without any folding or projections. It is selectively permeable to substances. That is from cytoplasm into the mitochondria and also from mitochondria into the cytoplasm.
Thus it can act as reserve for various substances needed for mitochondrial energy generation and excretion of related waste bi-products.
Check out →Mitochondrial characteristics
1. It is well known fact that mitochondria are responsible for cell energy supply.
2. They produce energy in the form of ATP (adenosine triphosphate) by breakdown of carbohydrate substrates in presence of oxygen. This is how the food in body is converted to energy. Once we consume food, it is digested and absorbed into blood. Then it supplied to each and cell and organ in the body.This is then used to generate the energy.
Check out→How food is converted to energy in the body for more details.
3. These are the organelles where the TCA cycle (tri-carboxyllic acid cycle) and other respiratory cycles of the cell takes place.
4. They also produce bi-products like glutarate, glyco-oxalic acid during the TCA cycle. These can further form glutamine, glycine like amino acids required for normal physiology and metabolism of the cell.
5. They promote cell growth and also signal transmission. In especially nerve cells they are concentrated at nerve ending to promote nerve growth and also supply energy for nerve conduction.
6. Mitochondria also are partly responsible for cell death in case of trauma. The membrane of mitochondria releases apoptosis factors leading to programmed cell death.
7. They also generate oxidative radicals during energy formation. These oxidative radical are necessary for various other reactions. But in excess can be harmful to the cell itself.