Where is the mitochondria?

Answer 1

Mitochondria:-

The mitochondria are dynamos encased inside double membranes. The outer one communicates with the cell, and the inner membrane contains machinery capable of converting food (glucose) to adenosine triphosphate (ATP), a chemical form of energy. Mitochondria are small, colorless, filamentous or tubular, granular structures present in the cytoplasm of all eukaryotic cell (except Mammalian RBC and sieve tube of Phloem). They are the site of cellular respiration and contain enzymes that involve in the breaking down of complex organic substances into simpler inorganic substances with the liberation of energy in the form of ATP. Thus, they are known as the Power House of the cell.

Size:- They are 1.5 to 10 µm in length, 0.25 to 1 µm in breadth and about 1 µm in diameter.

Shape:- The shape of mitochondria is determined by the physiological condition of cell. The shape may be oval, spiral, cylindrical, sausage shaped or filamentous.

Structure:- Mitochondria are rod-shaped structures and are double membrane bound cell organelles consisting of outer and inner membrane. The membranes are made up of phospholipids and proteins. The space between two membranes is known as Perimitochondrial space, which has the same composition as the cytoplasm of the cell. However, the protein content in this space differs from that in the cytoplasm. The structure of Mitochondria can be described as below:

Outer Membrane: The outer membrane is smooth and has almost the same amount of phospholipids as proteins. It has a large number of special proteins. The outer membrane is completely permeable to nutrient molecules, ions, ATP and ADP molecules.

Inner Membrane:

The inner membrane is more complex in structure as it contains the complexes of the electron transport chain and the ATP synthesizing complex. It is permeable only to oxygen, carbon dioxide and water. It is made up of a large number of proteins that play an important role in producing ATP, and also helps in regulating transfer of metabolites across the membrane. The inner membrane is thrown into a number of pegs like projections towards inner side and has infoldings known as Cristae. The Cristae and inner membrane contains a number of tennis racket like structures known as Oxysome or Elementary particlesor F1 particles. They are the site of respiration. The inner membrane encloses matrix of fluid, which contain circular DNA, RNA, Ribosome, amino acids, proteins and enzymes.

Matrix:

The matrix is a complex fluid mixture of enzymes that are enclosed by inner membrane. It is important for the synthesis of ATP molecules, special mitochondrial ribosome, TRNAs, the mitochondrial DNA, proteins and enzymes. Besides these, it has oxygen, carbon dioxide and other recyclable intermediates.

Mitochondria are self-duplicating cell organelles. They are commonly known as Semi-autonomous cell organelles because they contain machinery (DNA, RNA) for protein synthesis. However, they partially depend on nuclear DNA for performing other functions.

Functions of mitochondria:-

1. The complete oxidation of organic food material into simple inorganic substances (carbohydrates, fats, etc.) with the liberation of energy in the form of ATP takes place in Mitochondria. The entire process of liberation of energy in the form of ATP that occurs in mitochondria is known as oxidative phosphorylation. As well as they help in other metabolic activities of the cell. Thus, they are known as the Power House of the cell.

2. They help in the synthesis of amino acid (such as; Glutamic acid, Aspartic acid, etc.), fatty acid, hemoglobin and hormones (like testosterone and estrogen).

3. They provide intermediate for the synthesis of Chlorophyll, Pyrimidine (nitrogen base), Steroids, Cytochromes and Alkaloids (complex organic substance and nitrogen containing bases found in the roots of medicinal plants).

4. They help in balancing calcium-ion concentration in a cell.

5. They forms middle piece of sperm.

6. They help in the development of yolk during ovum formation.

7. They play an important role in the process of programmed cell death. Unwanted and excess cells are pruned away during the development of an organism. The process is known as apoptosis. Abnormal cell death due to mitochondrial dysfunction can affect the function of the organ.
In cells.

Answer 2

The mitochondria are located in the cytoplasm of the cell.

Answer 3

inside cells.