They grow best at 37 C.
In this essay we will discuss about Bacteria. After reading this essay you will learn about: Meaning of Bacteria 2. Salient Features of Bacteria 3. The bacteria constitute a very wide group of microorganisms that exhibit a fascinating diversity in morphology, habitat, nutrition, metabolism, and reproduction.
Although they are not very complex morphologically, the tiny bacteria nevertheless have highly complex physiological, biochemical, cytological, and genetically characteristics making them a valuable tool for understanding the various intricacies of life.
Due to their extreme simplicity in structure, small size favouring rapid cell division, highly resistant nature and diversified mode of nutrition, bacteria are of universal occurrence. They are present in our mouth and flourish in intestine. They are present in air we breathe and in food we eat.
They abundantly occur in fresh and salt water, soil water and even in ice. Their most favourable habitat is soil, where they occur in abundance mainly in the upper half feet. In a handful of garden soil, the bacterial population may outnumber the human population on the earth.
They live in all conditions not fatal to living beings and are among the most numerous of all living beings present in almost every conceivable environment. Some bacteria are deadly parasites of plants, animals and human beings; some live as mutualists with plants or as commensals in the alimentary canals of animals.
Salient Features of Bacteria: Bacteria eubacteria are microscopic and least differentiated living organisms, believed to be the first primitive organisms on our planet. They are the typical prokaryotes and also possess characters resembling both the plants and the animals.
Bacteria show considerable variation in characters almost themselves, they possess many characters common to all. Such common characters of bacteria are the following: They are omnipresent and occur in all possible habitats one can think of.
Most of the bacteria have heterotrophic absorptive mode of nutrition, i. Some bacteria are autotrophic; they possess bacteriochlorophyll and synthesize their own food. Bacteria are usually single-called and morphologically least complex of all the living organisms. Bacteriochlorophyll pigments, whenever present, are located within involuted cytoplasmic membranes; well organised plastids are absent.
Bacterial cell wall is a dense layer surrounding the plasma membrane and functions to give shape and rigidity to the cell. The main constituent or back-bone of bacterial cell wall is peptidoglycan also known murein, muranic acid or mucopeptidewhich is biochemically unique and is absent in cell walls of archea archaebacteria or any eukaryote.
A well organised nucleus, characteristic of eukaryotes, is lacking and descrete chromosomes are also absent. The nuclear material is not surrounded by nuclear membrane and is usually called nucleoid. Bacterial DNA have no histone proteins and nucleosomes. The organelles like mitochondria, endoplasmic reticulum, Golgi apparatus are absent.
The function of mitochondria is carried out by complex localized in folding of plasma membrane known as mesosomes. Ribosomes occur abundantly and freely in the cytoplasm of a bacterial cell. Each ribosome has a sedimentation coefficient of 70S and is made up of two subunits of 50S and 30S each consisting of roughly equal amounts of rRNA and protein.
Bacteria reproduce asexually and multiply most commonly by binary fission. True sexual reproduction is absent. The sexuality is completed by genetic recombination methods called conjugation, transformation and transduction. The motile bacteria possess one or more flagella.Escherichia coli.
Description and Significance. similar to most bacteria, E. coli can transfer its DNA materials through bacterial conjugation with other related bacteria to produce more mutation and add more strains into the existing population. Escherichia coli can be commonly found in lower intestines of human and mammals.
Other compounds of significance to bacteria include phosphate, sulfate, and nitrogen.
Low levels of phosphate in many environments, particularly in water, can be a limiting factor for the growth of bacteria, since many bacteria cannot synthesize phosphate. Talk:Bacteria Jump to navigation This article has been rated as Top-importance on the project's importance scale.
I think it's a great addition for the pages on life and its evolution, but for a page on bacterial origins, I think the first sentence about how microbial life emerged ~4 billion years ago is sufficient.
The latest estimates. Gram staining is performed in-vitro and is used to identify a bacterial organism based on the amount of peptidoglycan present in its cell wall. The result classifies bacteria as either gram.
Gram staining is a differential staining technique that differentiates bacteria into two groups: gram-positives and gram-negatives. The procedure is based on the ability of microorganisms to retain color of the stains used during the gram stain reaction.
Bacteria, singular bacterium, any of a group of microscopic single-celled organisms that live in enormous numbers in almost every environment on Earth, from deep-sea vents to deep below Earth’s surface to the digestive tracts of humans.