Micro Bodies: Types, Structure and Function

Introduction

Cells are the functional and structural units of the body that are found in all living things. Cells are composed of protoplasm. It is joined via cell membranes or plasma membranes and also has a nucleus. The nucleus and cytoplasm make up protoplasm, which is one of the important components of the cell. Mitochondria, golgi bodies, endoplasmic reticulum, ribosomes, lysosomes and plastids are all organelles located within the cytoplasm of the cells. The cells also contain some other structures bound by a sac-like single membrane. These structures are called microbodies.

The three primary types of microbodies and their functions are as follows:

Lysosome:

Lysosome term is made up of two words: ‘lyso’ which means digestive and ‘soma’ which means body. The endoplasmic reticulum produces lysosomes and their hydrolytic enzymes, which are then transported to the golgi body for more preparation. Some lysosomes are thought to form via budding from the golgi apparatus’s trans face.

Structure:

1. Lysosomes are spherical sacs with no interior structure that are enclosed by a single membrane. They usually have a diameter of  0.2–0.3 μm.
2. They include digestive, hydrolytic enzymes that are encased in a single membrane to prevent damage to the other cell organelles.

Functions:

1. They possess hydrolytic enzymes, which are used to degrade biomolecules by several eukaryotic cells.
2. Lysosomes contain hydrolytic enzymes, which are used by cells to conduct intracellular molecules digestion in a number of situations.
3. Lysosomes are used by some single-celled organisms, such as amoeba, to digest the ingested food in the vacuole.
4. In an acidic environment, these enzymes perform optimally. Because the cytosol pH is neutral, if the lysosome membrane cracks and the contents flow out, the enzyme would not harm the cell or its organelles. Excessive leakage from a high number of lysosomes, on the other hand, can cause a cell to self-destruct due to digestion.
5. With the help of their hydrolysing enzymes, lysosomes decompose undesirable components, such as decrepit organelles or even complete cells.
6. White blood cells use lysosomes to decompose microorganisms.
7. By permitting sperm to penetrate the ovum, they aid in the fertilisation process. The sperm head contains the acrosome, a lysosome that digests the ovum’s top layer before entering it.
8. Phagocytosis is also carried out by some human cells. Macrophages, immune system cells which allow the body to protect itself by engulfing and eliminating bacteria, as well as other pathogens, were among them.

Peroxisomes:

It is present in the green leaves of higher plants. Plant and animal cells both contain them. They emerge via pre-existing peroxisomes, which expand by receiving a cytosolic protein. It can be identified by a class of peroxisomal membrane receptor proteins known as peroxins. The peroxisome then splits by fission. It lives for 5 to 6 days on average.

Structure:

1. 1. 1. Peroxisomes are membrane-bound, spherical, or ovoid organelles that may be detected in cells via a catalase cytochemical reaction. The hepatocytes have bigger peroxisomes that can be observed in the laboratory.
      2. They are frequently seen in close proximity to the endoplasmic reticulum.
      3. They appeared as tiny organelles with a diameter of 0.1–1 μm in stain preparations.
      4. The core is crystalline and nucleoid, which contain urate oxidase. However, there is no nucleoid present in the peroxisomes of human cells.

Function:

1. There are enzymes present in the peroxisomes that oxidise the long-chain fatty acids.
2. Using their enzyme, they participate in the synthesis of cholesterol.
3. They are involved in the detoxification of substances such as ethanol and hydrogen peroxide, which are harmful to the body cells.
4. Some of its enzymes, called peroxisomal enzymes, initiate the synthesis of plasmalogen. This substance is the major phospholipid component of myelin.
5. Plant cells also use it in photorespiration.

Glyoxysomes:

Glyoxysomes, a type of specialised peroxisome, are identified in plant cells. Glyoxysomes microbodies, which are closely indistinguishable from peroxisomes, are found in the fat-storing sections of plant seeds.

1. Present in yeast cells and some fungi, as well as the seeds of plants, which are rich in fat.
2. 1. They participate in the synthesis of carbohydrates from the stored fat to provide the required energy to the seed during germination using its fatty acid metabolism enzymes. This is important because, at this stage, they are not able to synthesise their own carbohydrate as they lack photosynthesis.