Lysosomes are the cellular organelles that contain digestive enzymes that break down waste materials, foreign materials and foreign particles that entered cell. It helps the cell to process its nutrients and is responsible for destroying the cell after it has died. It is bounded by only one single membrane. It break-down the structures within the cells. However in certain circumstances may be in case of diseases or some conditions lysosomes begin to break-down living cells. This article deals with why lysosomes are known as suicidal bags of the cell, Importance of lysosomes, its structure and formation.
What are Lysosomes?
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Lysosomes are present in animal and are membrane-bound organelles. They have single outer membrane which consists of acid hydrolase enzyme that helps in breaking-down macromolecules and a phospholipid bilayer.
What is the structure of lysosomes?
Lysosomes are spherical organelles which contain a single layer membrane, but its shape and size varies. They are generally very small, ranging from 0.1 to 0.5 µm but they can reach up to 1.2 µm. The lipids that make up the bilayer are phospholipids, which are molecules that have hydrophilic phosphate group heads, a glycerol molecule, and hydrophobic fatty acid tails. When they are placed in a solution containing water phospholipids naturally form double-layered membranes, the phosphate group head move outside the layer and fatty acid tail move inside of the layer away from water.
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Structure of Plant and Animal Cell
Do you know phospholipids make many other membranes in the cell like nuclear membrane that surrounds the nucleus, golgi apparatus and endoplasmic reticulum.
Lysosomes are formed by budding off of the Golgi apparatus, and the hydrolytic enzymes within them are formed in the endoplasmic reticulum. The enzymes are tagged with the molecule mannose-6-phosphate, transported to the Golgi apparatus in vesicles, and then packaged into the lysosomes.
Various types of enzymes are found in lysosomes like proteases, amylases, nucleases, lipases and acid phosphatises etc. The function of enzyme is to break down the molecules in to simpler ones like proteases break down proteins, nucleases break down nucleic acids, amylase break down starch in to sugar etc.
Functions of Lysosomes
- They digest many complex molecules like carbohydrates, lipids, proteins and nucleic acids which cell recycle them for further uses.
- They release enzyme outside the cell, which help in destroying materials around the cell and this process is known as exocytosis.
- The pH of lysosomes is acidic around 5 because its hydrolytic enzyme works properly in this pH rather than neutral pH of the cell.
- They break-down digestion of material from inside the cell by fusing with vacuoles from inside the cell which include digesting worn-out organelles so that useful chemical remains inside the cell itself for further using them again. This process is known as autophagy.
Nutrition in Animals
- When they break-down materials from outside the cell by fusing with vacuoles from outside the cell which include breaking down material taken-in by phagocytes which include white blood cells etc. Various heterophagy are:
- Phagocytic – by which cells engulf extracellular bacteria or other particles. This is also known as cell-eating.
- Pinocytic – by which cells engulf extracellular fluid.
- Endocytic – by which cells take up particles like molecules that have become attached to the outer surface of the cell membrane.
- They also completely break down the cells that have died and this process in known as autolysis.
- It also do biosynthesis that is recycle the products of biochemical reactions which brought in to the cell by endocytosis. Several materials or chemicals are processed in different ways.
Generally we can say that lysosomes involves breaking-down that is process of making the cell safe, remove waste material or unhygienic things which harms the cell out of it by exocytosis or useless material like worn-out parts of the cell or potential threats like bacteria. Therefore, Lysosomes are also known as rubbish disposal units.
Why Lysosomes are known as suicidal bags of the cell?
Lysosomes can be termed as waste disposal system of the cell. For almost all type of organic materials they contain digestive enzymes. For example, when cell gets damaged, lysosome may burst and the enzymes digest their own cell. Therefore lysosomes are known as the Suicidal bags of a cell or we can say that they posses different kind of hydrolases on release of these enzymes that cause death of cell.
From the article it is clear that lysosomes are specialized vesicles within cells that digest large molecules through the use of hydrolytic enzymes. They are also known as suicidal bags. On the other hand it is clear that lysosome are vesicular organelles that meet certain criteria and are found in animal cells where as vacuole refer to similar organelles that are found in plants, fungi and algae.