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Cell Peroxisomes Structure and Function

    In this cell peroxisomes structure and function post we have briefly explained about peroxisomes, history, cell number, origin of peroxisome, structure, peroxisomes in animal cells mechanism and functions.

    Peroxisomes in animal cells are small, membrane enclosed organelles that contain enzymes that are involved in a wide range of metabolic activities, including energy metabolism.

    Cell Peroxisomes Structure and Function

    A microbody is a peroxisome. Peroxisomes and glyoxysomes are two different forms of microbodies. Peroxisomes  in animal cells are solitary membrane-bound organelles that are structurally and functionally identical to lysosomes. In 1954, Rhodin coined the phrase “microbodies.”

    History

    Christian de Duve and colleagues discovered peroxisome. Rodin, on the other hand, discovered it for the first time in liver and kidney cells.

    The generation of hydrogen peroxide inside it gives it the name peroxisome. Plant cells and eukaryotic cells both have peroxisomes. It’s present in paramecium in invertebrates.

    Cell number

    Peroxisome number and size differ from cell to cell, depending on cell type and environmental factors.

    When glucose is fed to baker’s yeast, for example, modest numbers of peroxisomes are observed. When baker’s yeast is supplied exclusively long chain fatty acids as a source of carbon, however, it can produce up to 25 peroxisomes.  A liver and kidney cell, for example, can have 70 to 100 peroxisomes in animal cells.

    Origin of Peroxisome

    Peroxisomal precursor vesicles are extensions of the endoplasmic reticulum (ER) that bud out to generate vesicles called peroxisomal precursor vesicles.

    Peroxisomes  in animal cells are formed when these precursor vesicles absorb enzymes and nutrients from the cytoplasm.

    If the peroxisomes in animal cells receive enough protein and phospholipid material from the cytosol and the endoplasmic reticulum, they may grow in size and divide into two.

    Peroxisomes in Animal Cells

    Peroxisome

    Cell Peroxisomes Structure and Function: Peroxisomes in Animal Cells

    Structure

    It’s a spherical or oval-shaped cell organelle with a single membrane bordered membrane.

    It has a diameter of 0.1 to 0.5 micrometres and a lipid bilayer membrane similar to that of a plasma membrane.

    Its primary function is to produce and degrade hydrogen peroxide. It also features a crystalline core because Urate oxidase is present in crystalline form in the centre.

    Mechanism

    Various toxic chemicals, such as urea, uric acid, and access amino acids, are generated during the metabolism or breakdown of proteins, along with helpful compounds. Peroxisomes in animal cells allow hazardous substances to enter the body.

    There are two types of enzymes in it. The first is oxidase, and the second is catalase. D-amino acid oxidase, alpha hydroxy acid oxidase, and beta hydroxy acid oxidase are oxidase (peroxidase) enzymes. Peroxisomes in animal cells oxidise uric acid, urea, and other compounds in the presence of the oxidase enzyme, releasing hydrogen peroxide and hydrocarbon. The oxidase enzyme takes hydrogen from the compounds and combines it with oxygen to generate hydrogen peroxide in this process. For example; RH2 + O2 → R + H2O2 (where R is an organic substrate)

    Because of its corrosive nature, hydrogen peroxide is not beneficial for the cell. As a result, it must be removed right away. The second enzyme, catalase, transforms hydrogen peroxide into water and oxygen, both of which are non-toxic, protecting the cell. For example; 2H2O2 → 2H2O + O2

    As a result, the reactive oxygen species (ROS) that can harm the cell are degraded. Tobacco, radiation, and medications all produce reactive oxygen species (ROS), such as oxygen ions or peroxides, as a by-product of regular biological reactions. ROSs induces oxidative stress, which can harm DNA and lipid-based substances such as cell membranes. Antioxidants are also used to keep this from happening.

    It also breaks down fatty acid molecules, such as oil molecules, to produce energy. Apart from that, peroxisomes in animal cells, like lysosomes, contain enzymes. Unlike the lysosome, which mostly degrades proteins, the peroxisome primarily degrades long fatty acids, a process known as lipid catabolism.

    Functions

    1. They are in charge of eliminating toxins from the body. They convert uric acid, an amino acid, to hydrogen peroxide, and then convert hydrogen peroxide to oxygen and water to protect cells from hydrogen peroxide’s damaging effects.

    2. It cleanses the liver of alcohol and drugs by eliminating hydrogen from alcohol and replacing it with oxygen.

    3. Photorespiration occurs in peroxisomes in animal cells, which are found in plant cells. It breaks down fatty acids into smaller molecules in the presence of oxygen.

    4. They play a role in lipid metabolism, such as beta-oxidation of fatty acids, cholesterol production, and steroid hormone synthesis, among other things. D-amino acids, bile acids, and polyamines are all catabolized by them.

    5. Photosynthesis is aided by peroxisomes found in green leaves. They, like chloroplasts, engage in photorespiration.

    6. It facilitates seed germination. It transforms stored fatty acids into carbs, providing energy and raw materials for germinating plants’ growth.

    7. It also contains enzymes that help produce plasmalogens, which are a key component of the membranes in the brain and heart.

    8. Peroxisomes in animal cells in fireflies contain the luciferase enzyme, which aids bioluminescence and hence aids in the finding of a mate.

    9. The enzyme urate oxidases take part in the catabolism of amino acids, polyamines and purines (nitrogenous bases found in nucleic acids like DNA and RNA).

    10. It aids in the production of phospholipids, which are essential components of the cell membrane.

    11. They contain oxidising enzymes that help with gluconeogenesis (glucose synthesis) in animal cells.

    12. They participate in photorespiration in leaves and are involved in the oxidation of glycolates produced in the chloroplast by photosynthesis.

    13. It uses catalase to break down hydrogen peroxide (H2O2), which is generated during photorespiration, into water and oxygen, protecting the cell from hydrogen peroxide’s damaging effects.

    Further Readings

    Reference