Biology – Microorganisms (Introduction to Bacteria) – CBSE Class 8
By Micah Moen
The most special day of the year is our Birthday! And birthday gets with it a delicious birthday cake! But what if cakes were never so delicious and fluffy? Well the fluffiness is all thanks to the YEAST that helps it get spongy! But the yeast is just so tiny! And how can it help us so much? Well, there are several organisms tinier than yeast that help us to obtain many useful products. These little creatures are called MICRO-ORGANISMS! Now as the name says, Micro means very small or microscopic structures, while organisms are living beings. Thus, those organisms which cannot be observed with naked eyes, and require a microscope to be seen, are the Micro-organisms. These tiny creatures come in various shapes, forms, and structures. For studying them, a proper categorisation is really necessary. Thus, we classify these micro-organisms, simply referred to as microbes, in four major classes: Bacteria, Fungi, Protozoa and Algae. Let’s get introduced to each. Let us begin with Bacteria first. They are usually unicellular prokaryotic organisms. What do we mean by this? Unicellular as the name suggests, are made up of single cell . So the entire body of the organism consists of just one cell? Yes! That is how it is! And what do we mean by Prokaryotic? Well, the word arises from two Greek terms. The term “Pro” means “before” that refers to Primitive form. Whereas the term “Karyon” means “kernel or nut” and here it refers to a membrane bound nucleus. So Prokaryotic organisms are those which do not have a proper, well-defined nucleus . As we can see here , in these organisms the genetic material is randomly scattered in the cytoplasm. So when we say that Bacteria are unicellular prokaryotes, it means they have a single cell which is of a primitive type, without a well-defined nucleus. Would studying them be simpler then? Not really! Bacteria, in spite of their unicellular and prokaryotic nature, come in diverse forms. They come in various shapes and sizes, and are present almost everywhere around us. So how do we study so many types? It’s simple! We classify them into categories. Based on their SHAPES, we classify them into four major groups. As we can see here, the spherical ones called Coccus , or plural Cocci. Then these rod-shaped ones called Bacillus or plural Bacilli. Then we have these comma-shaped bacteria called Vibrio , plural Vibrios. And lastly, we have these spiral shaped ones called the Spirillum or plural Spirilla. There are numerous other ways of classifying the bacteria. However, we restrict ourselves to only this one simple type: based on shapes! Now where do you think these bacteria will be found? In isolated places? Or scattered at specific points? Will they be found only on land? Or only in water? Or both? Well there is single word which describes their presence; and that word is “EVERYWHERE ”! Yes! There is no single place on this earth where you won’t find bacteria! May it be the hot springs, or the ice cladded regions. May it be the salty Dead Sea, or even the marshy lands. They are present everywhere! And let me tell you an amazing fact! Some of them are even present inside you! But don’t worry! The ones inside you are like friends! They won’t harm you in any way! Well this was about the various types of bacteria in short. Now we need to take a look at the next category of micro-organisms as well. Let’s talk about Fungi in the next video.