BlogNCERTMitochondria 

Mitochondria 

Introduction:

Mitochondria is one of the cell organelle or we can say an important cell organelle of the living cell. Mitochondria is a double membrane organelle found in the cytoplasm of the cell mostly in eukaryotes which have a definite nucleus. It supplies power by producing ATP and stores some elements. It is oval in shape. We will call it a powerhouse of the cell. Why do we call it that? Because it supplies energy to other organelles which are used in other processes like respiration, photosynthesis.

What actually a mitochondria is? What are its functions? How does it provide energy to cells? Except ATP didn’t it perform in another function? How is mitochondria organized? What actually goes inside mitochondria? You will get all answers to these questions. We are going to learn all about mitochondria. So, let’s move further in studying mitochondria.

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    Overview:

    Mitochondria is a double membrane organelles found in cytoplasm of eukaryotic organisms which are having definite nuclei. Their main function is to produce energy by utilizing oxygen which is produced in aerobic respiration and some other materials. But in some eukaryotes mitochondria is not found like in mature mammalian red blood cells.

    Mitochondria is in an oval shape with 0.5 to 10μm in size. Besides producing energy to the cell it also plays a role in cell signalizing, cell growth and death, and generating heat for the cell. They are power-generating cell organelles. Mitochondria is also known as the powerhouse of the cell. They contain their own genome. The inner mitochondrial membrane contains electron transport proteins like the plasma membrane of prokaryotes and mitochondria also have their own prokaryote-like circular genome.

    Albert discovered mitochondria in 1880 in voluntary muscles of animals. Philip in 1957 named the mitochondria, the powerhouse of the cell. The count of mitochondria varies depending on the cell tissue. In mature blood cells, mitochondria are absent whereas if you see in the liver there are numerous mitochondria. Let us study the structure of mitochondria.

    Structure of mitochondria:

    Mitochondria size varies depending on the tissue and the shape is mostly oval in shape. The mitochondria have an outer membrane, inner membrane, phospholipid layer, and proteins in them. The two membranes have different functions. The space between the outer and inner membrane is known as inner membrane space. You can find cristae in them which are formed by foldings of the inner membrane. Matrix is the fluid present in the inner membrane.

    Outer membrane:

    Outer membrane encloses the total organelle; it is a protein phospholipid membrane, the same as the cell membrane. It contains a large number of proteins known as porins. The outer mitochondrial membrane can associate with the endoplasmic reticulum membrane in a structure known as mitochondria-associated ER membrane. The important function is calcium signaling and also involves the transfer of lipids between the ER and mitochondria. Outside the outer membrane, small particles are present.

    Intermembrane space:

    The space is present between the outer membrane and the inner membrane. It is a peri mitochondrial space. While transferring large proteins through the outer membrane, the intermembrane needs a specific sequence while comparing inner membrane space which is known as cytosol.

    Inner membrane:

    The inner membrane consists of proteins that perform different functions. Some of the functions performed are:

    • Take part in electron transport redox reaction
    • ATP synthase
    • Specific transfer of proteins

    It contains polypeptides and has a very high amount of proteins and phospholipids. Porins are absent in the inner membrane, highly impermeable to all molecules. Proteins also have enzymes that are needed in the catalyzing process and in the production of ATP. The inner mitochondrial membrane is permeable to oxygen, carbon dioxide, and water. The inner mitochondrial membrane is the site of ATP generation. Several fold like structures is present which are known as cristae.

    Cristae:

    The inner membrane of mitochondria is folded into several folds. Cristae increase the surface inside the mitochondrial membrane to generate ATP molecules. The larger the surface the more space will be available to carry out cell functions. Exosomes are present on cristae which aid the osmosis of ions. Many chemical reactions occur in mitochondrial inner membrane cristae.

    Matrix :

    The space in the inner membrane apart from the cristae is all known as matrix. Matrix is the fluid part having proteins, ribosomes, enzymes, and tRNA with genomic DNA. It synthesizes RNA and proteins. Synthesis of ATP will not complete without enzymes which are in matrices which are very important in cycles.

    Functions of mitochondria:

    The main role of mitochondria is to produce the energy currency of the cell ATP which is Adenosine TriPhosphate by aerobic respiration. There are some cycles from which we can produce ATP. They are krebs cycle, citric acid cycle. Even though this is the main function it also takes part in other functions also cellular metabolism.

    It is responsible for cell growth and metabolism. It also plays a role in cellular sucide. It stores calcium ions which help in cellular signaling. Cellular proliferation takes place. Some metabolic functions that take place are:

    1. Role in signaling
    2. Regulating membrane potential.
    3. Takes place in cellular sucide.
    4. Storing of calcium ions.
    5. Certain heme synthesis reactions.
    6. Steroid synthesis.
    7. Mitochondria are sensitive and respond to hormones.
    8. Immune signaling.
    9. Cellular quality control by reporting neuronal status towards microglia through specialized somatic junctions.
    10. And also takes place in cellular differentiation and cell senescence.

    Importance of this chapter in neet:

    This chapter takes the main role as it explains the main role of organelle in living cells. As it explains the mitochondria functions and their parts. The structure of mitochondria and the role they paid in metabolism or other activities.

    We should study this chapter as it tells the cell organelle where the cell is the basic unit of life. We need to learn it basically. Examiner won’t give a question paper by leaving this area questions.

    Mitochondria is the powerhouse of the cell, it is the main part or organelle of the cell which we just can’t leave while preparing for our competitive exams. We just know the main function of mitochondria; many of us don’t know the other functions it plays in cells.

    So, there is a chance of asking questions about the other functions of mitochondria except for energy production. We can say that two to five bits can come from this area which is good to score high marks.

    If you failed to get the information about cell organelles or mainly about important cell organelles, anyone can guarantee you of scoring high. So, don’t neglect this area which brings you to score easily.

    Also read: Structure of Proteins

    Frequently Asked Question FAQs:

    Question: What is mitochondria?

    Answer: Mitochondria is a double membrane-bound organelle that is found in eukaryotic cells except in red blood cells. It is also known as a powerhouse of the cell because its main function is to produce energy by producing adenosine triphosphate in aerobic respiration.

    Question: Write details about mitochondria?

    Answer: Mitochondria is a double membrane organelles found in cytoplasm of eukaryotic organisms which are having definite nuclei. Their main function is to produce energy by utilizing oxygen which is produced in aerobic respiration and some other materials. But in some eukaryotes mitochondria is not found like in mature mammalian red blood cells.

    Mitochondria is an oval shape with 0.5 to 10μm in size. Besides producing energy to the cell it also plays a role in cell signalizing, cell growth and death, and generating heat for the cell.

    They are power-generating cell organelles. Mitochondria is also known as the powerhouse of the cell. They contain their own genome. The inner mitochondrial membrane contains electron transport proteins like the plasma membrane of prokaryotes and mitochondria also have their own prokaryote-like circular genome.

    Albert discovered mitochondria in 1880 in voluntary muscles of animals. Philip in 1957 named the mitochondria the powerhouse of the cell. The count of mitochondria varies depending on the cell tissue. In mature blood cells, mitochondria are absent whereas if you see in the liver there are numerous mitochondria. Let us study the structure of mitochondria.

    Question: What are the functions of mitochondria?

    Answer: Functions of mitochondria:-

    The main role of mitochondria is to produce the energy currency of the cell ATP which is Adenosine TriPhosphate by aerobic respiration. There are some cycles from which we can produce ATP. They are: krebs cycle, citric acid cycle. Even though this is the main function it also takes part in other functions also cellular metabolism.

    It is responsible for cell growth and metabolism. It also plays a role in cellular sucide. It stores calcium ions which help in cellular signaling. Cellular proliferation takes place. Some metabolic functions that take place are:

    1. Role in signaling
    2. Regulating membrane potential.
    3. Takes place in cellular sucide.
    4. Storing of calcium ions.
    5. Certain heme synthesis reactions.
    6. Steroid synthesis.
    7. Mitochondria are sensitive and respond to hormones.
    8. Immune signaling.
    9. Cellular quality control by reporting neuronal status towards microglia through specialized somatic junctions.
    10. And also takes place in cellular differentiation and cell senescence.

    Question: Write the structure of mitochondria?

    Answer: Mitochondria size varies depending on the tissue and the shape is mostly oval in shape. The mitochondria has an outer membrane, inner membrane, phospholipid layer and proteins in them.

    The two membranes have different functions. The space between outer and inner membrane is known as inner membrane space. You can find cristae in them which are formed by foldings of the inner membrane.

    Matrix is the fluid present in the inner membrane.

    • Outer membrane:

    The outer membrane encloses the total organelle; it is a protein phospholipid membrane, the same as the cell membrane. It contains a large number of proteins known as porins.

    The outer mitochondrial membrane can associate with the endoplasmic reticulum membrane in a structure known as mitochondria-associated ER membrane. The important function is calcium signaling and also involves the transfer of lipids between the ER and mitochondria. Outside the outer membrane, small particles are present.

    • Intermembrane space:-

    The space is present between the outer membrane and inner membrane. It is a peri mitochondrial space. While transferring large proteins through the outer membrane, the intermembrane needs a specific sequence while comparing inner membrane space which is known as cytosol.

    • Inner membrane:-

    The inner membrane consists of proteins that perform different functions. Some of the functions performed are:

    Take part in electron transport redox reaction

    ATP synthase

    Specific transfer of proteins

    It contains polypeptides and has a very high amount of proteins and phospholipids. Porins are absent in the inner membrane, highly impermeable to all molecules. Proteins also have enzymes that are needed in the catalyzing process and in the production of ATP.

    The inner mitochondrial membrane is permeable to oxygen, carbon dioxide, and water. The inner mitochondrial membrane is the site of ATP generation. Several folds like structures are present which are known as cristae.

    • Cristae:-

    The inner membrane of mitochondria is folded into several folds. Cristae increase the surface inside the mitochondrial membrane to generate ATP molecules. The larger the surface the more space will be available to carry out cell functions. Exosomes are present on cristae which aid the osmosis of ions. Many chemical reactions occur in mitochondrial inner membrane cristae.

    • Matrix:-

    The space in the inner membrane apart from the cristae is all known as matrix. Matrix is the fluid part having proteins, ribosomes, enzymes, and tRNA with genomic DNA. It synthesizes RNA and proteins. Synthesis of ATP will not complete without enzymes which are in matrices which are very important in cycles.

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