Bacteria | What are bacteria and what do they do?
In this article we are goin to discuss about bacteria so before we discuss we have to know the definition of bacteria and what are bacteria and what do they do? Types, Structure, Feeding, Where do they live?, Reproduction and transformation, Uses, Hazards, Resistance, The gut microbiome, History of bacteria so let’s start from introductions.
TABLE OF CONTENTS
- WHAT ARE BACTERIA
- TYPES OF BACTERIA
- GRAM POSITIVE BACTERIA
- GRAM NEGATIVE BACTERIA
- BAD BACTERIA
- SYMPTOMS CAUSED BY BAD BACTERIA
- STRUCTURE OF BACTERIA
- HETEROTROPHIC BACTERIA
- AUTOTROPHIC BACTERIA
- WHERE DO BACTERIA LIVE
- REPRODUCTION AND TRANSFORMATION
- USES OF BACTERIA
- HAZARDS OF BACTERIA
Bacteria are tiny organisms that are single celled which subsist in their millions in every habitat, both outside and inside of different creatures.
Bacteria can be both harmful and useful. Some can serve harm to the body and while some groups of bacteria can be beneficial to the body as well as the environment in which they are living.
Bacteria today are used in many forms of life such as in medicinal and industrial purposes. Both forms of plants and animals are served by bacteria.
About 4 billion years ago , it was well said by scientists that the bacteria were the first ever creatures to have existed on the earth. There were bacteria like organisms found on the fossils of olden times.
Bacteria can also survive in very extreme conditions and can use both organic and inorganic food components.
“Even if new medicines are developed, without behaviour change, antibiotic resistance will remain a major threat.”
World Health Organization (WHO)
WHAT ARE BACTERIA?
Bacteria are tiny organisms that are single celled which subsist in their millions in every habitat. They can neither be categorized as plants nor animals.
They usually are present in communities in millions of amounts in just a few micrometers in length.
A typical gram of soil just contains nearly 4 million bacteria. Usually 1 million bacteria can be found in just a few drops of fresh water.
There are almost 5 nonillions of bacteria present today on the earth and the biomass of the earth mostly is said to be made up of bacteria.
TYPES OF BACTERIA
There are many different types of bacteria present in today’s world. They can be classified on the basis of various categories one way of categorizing is on the basis of shape. There are in total three general shapes of bacteria present. These can be classified as :
Spherical , Rod shaped and spiral
Talking about these in detail,
In the spherical shape , the bacteria are shaped like a ball in sphere shape. These are known as cocci.
A single bacterium can be called a coccus.
The examples of this group include the streptococcus group of bacteria which is responsible for strep throat.
- Rod shaped
These are well known as bacilli. A single bacterium is known as bacillus. The curved shape is present in some rod shaped bacteria. These can be called vibrios. The examples of the rod shaped group include the Bacillus Anthracis or the antrax.
The spiral shaped bacteria are also called spirilla . The single bacterium is known as spirillum. They are very well known as spirochetes if their coil is very tight. The diseases which are caused by this category include Leptospirosis , Lyme Disease and syphilis.
However, there can be many variations found within each of the shape groups.
GRAM POSITIVE BACTERIA
The study of bacteria is known as bacteriology. In bacteriology, gram positive bacteria are those bacteria in which a positive test result is given in the gram staining. Thus through this bacteria can be quickly classified according to their cell wall in two wide categories.
The crystal violet stain is taken by the gram positive bacteria which is used in the test and then thus they appear to be violet or deep purple coloured when viewed from the microscope. This happens because the stain is retained and stopped by the peptidoglycan layer that is thick. After that it is washed away from the sample rest and in the decolorizing state.
The following conditions are fulfilled by the gram positive bacteria:
- Cytoplasmic lipid membrane
- Thick peptidoglycan layer
- Teichoic acids and lipids are also present forming lipoteichoic acids , which serves as the chelating agents and also for certain types of fixation.
- Cross linkage of peptidoglycan layer through which rigid cell walls are formed by a bacterial enzyme whose name is DD transpeptidase.
- A very tiny volume of periplasm than that in the gram negative bacteria.
Usually the polysaccharides consist of some species and the capsule.
GRAM NEGATIVE BACTERIA
Gram negative bacteria are those which do not hold on the crystal violet stain which is used in the gram staining procedure for bacterial identification. They are classified and identified by their cell envelopes , which consists of a lean peptidoglycan cell wall kept between an inner cytoplasmic cell membrane and an outer bacterial membrane.
Gram negative bacteria are found in all habitats on the Earth where life is supported.
The gram negative bacteria consists of the main organism Esceria coli and also many pathogenic bacteria which include pseudomonas aeruginosa , Chlamydia trachomatis , and Yersinia Pestis. All of these bacterias are a very big provocation to medical science as their outer membrane safeguards them from many antibiotics even including penicillin , detergents that would usually damage the peptidoglycans of the inner cell membrane, and lysozyme , which is an antibacterial enzyme given by animals that develop the part of the innate immune system.
Adding on , the external pamphlet of this membrane consists of a complex lipoprotein-polysaccharide whose lipid -A constituent can cause a harmful response , when these bacteria are recovered from immune cells. This harmful response can include fever , rise in respiratory rate and decline in blood pressure , which is a life endangering condition called septic shock.
Bad bacteria are nothing but those bacteria that cause serious problems and damage to the body and to the environment which can lead to severe illness , hospitalization of the patient and even death.
These are named under as follows:
- Clostridium perfringens
SYMPTOMS CAUSED BY BAD BACTERIA
The signs and symptoms that are caused by the effect of the bad bacteria on the human body are many in number. These are demonstrated below as follows.
- Watery diarrhea
- Abdominal cramps
- Nausea and vomiting
- Poor feeding to child
- Weak crying
- Poor muscle tone
- Double vision
- Blurred vision
- Drooping eyelids
- Slurred speech
- Muscle weakness
- Bloody diarrhea
STRUCTURE OF BACTERIA
The cells of bacteria are totally and entirely different from the plants and animal cells . All bacteria are prokaryotes which means that they do not have nucleus.
The cell of bacteria consists of :
The covering found on the outer side of the cell wall in some of the bacteria .
- CELL WALL
The covering is built of a polymer known as peptidoglycan. The shape of the bacteria is given by the cell wall. The cell wall is situated on the outer side of the plasma membrane. The cell wall is wide in some of the bacteria known as the gram positive bacteria.
- PLASMA MEMBRANE
The plasma membrane is identified in the cell wall itself. This brings about energy and conveys chemicals. The plasma membrane is permeable which means that it allows the entry and exit of several substances through it.
The cytoplasm is the gelatinous substance on the inner side of the plasma membrane which consists of the genetic substances and ribosomes.
The DNA contains all the genetic directions used in the growth and purpose of the bacterium. The DNA is located on the inner side of the cytoplasm.
The ribosomes are the components where proteins are developed. These are complex structures made up of RNA rich elements.
It is owned for motility. To move certain types of bacteria from one place to another. Various bacteria are present which consist of more than one flagellum.
Pili are the hairlike structures present on the outer surface of the cell which permit the bacteria to adhere to surfaces and transport genetic material to different cells.
The pili are also responsible for the illness and various kinds of diseases in human beings.
Bacteria take nutrition from different ways.
Heterotrophic bacteria , or heterotrophs obtain their power through ingesting organic carbon. Most bacteria soak up dead organic substances which include dead flesh. Many of the exploitative bacteria kill their own host whereas other bacteria help them.
Autotrophic bacteria are the ones which help in the making of their own food.
They take help from various sources like photosynthesis, water , carbon dioxide or with the help of sunlight.
They also take help from other substances in the form of chemo synthesis with the usage of water , carbon dioxide and certain other chemicals including ammonia, sulfur , nitrogen and others also.
The bacteria which inculcate the use of photosynthesis are known as photoautotrophs. Certain types which include cyanobacteria help in the production of oxygen. These, in all probability, play a very important role for the creation of oxygen in the earth’s atmosphere.
Oxygen is but not produced by others including helicobacter.
The bacteria that inculcate the use of chemo synthesis aur called as chemoautotrophs. These kinds of bacteria are mainly seen in the oceans , legume roots , such as alfalfa , clover , peas , beans , lentils and peanuts.
WHERE DO BACTERIA LIVE
Bacteria can be clearly established in soil, water , river , plants , animals , any kind of radioactive waste , deep side of the crust of earth, arctic ice and the glaciers also including hot springs.
REPRODUCTION AND TRANSFORMATION
Bacteria may or may not always reproduce or change. They use the following methods.
- BINARY FISSION
A cell continues to grow, until the formation of the new cell wall is formed from the middle , until two daughter cells are formed. This is the asexual form of reproduction. These hence are separated by making two different cells with the same genetic substance.
- TRANSPORT OF GENETIC MATERIAL
The cells obtain new genetic substances through the procedures called conjugation , transduction or the transformation. These procedures can build bacteria stronger and more ability to attain resistance from antibiotics.
When certain forms of bacteria have depletion in resources , they can help in the formation of spores. Spores always help in the holding of DNA material and consist of the enzymes required for germination. Spores are, although highly resistant to environmental pressures. The spores can remain in inactive form for many centuries until the right conditions have occurred. After this , they can reactivate and form into bacteria.
Endospores are the spores which are produced internally. For example Clostridium. It is mainly responsible for food poisoning and problems related to the intestine.
Exospores are the spores of bacteria that are formed externally. These are also called cysts.
USES OF BACTERIA
Humans would not be able to survive without bacteria. Bacteria are both good and bad. The activity of bacteria has led to the formation of oxygen which we breathe. Various uses of bacteria are listed below.
- NITROGEN FIXATION
Bacteria often take up the oxygen and leave it upto the plant to use when they are dead. Plants often require nitrogen into the soil to survive but they themselves cannot afford to do this on their own. When the plant has sprouted , they make use of the plant seeds which they have preserved.
- HUMAN SURVIVAL
An important role is played by the bacteria for the survival of human beings. Nutrients from the digestive system are broken down by bacteria like complex forms of sugars are broken down by bacteria in a form which the body can use.
- FOOD TECHNOLOGY
Lactobacillus and Lactococcus which are two lactic acid bacteria all together with the help of yeasts and molds or fungi are used in the preparation of food like cheese , soy sauce , nattoo , vinegar, yogurt and pickles.
Some of such kinds of foods definitely give health benefits and are also useful in the preservation of themselves.
HAZARDS OF BACTERIA
Various categories of bacterias can cause several kinds of diseases in human beings like cholera , diarrhea, diphtheria, dysentery, bubonic plague , tuberculosis, pneumonia, typhoid and various others.
If the bacteria are exposed to the human body which it doesn’t acknowledge as useful , the immune system will assault them . Due to all these , these reactions may cause the formation of swelling and inflammation that is seen by us. For example wounds that are infected.