what is characters constitute morphology? uses of characters constitute morphology? what is morphological analysis

Among the major characteristic of bacterial cells are their size, shape, structure and arrangement. these characters constitute morphology.
 bacteria are very small, most being app. is 0.5- 1.0 new µm In diameter
an important consequence of small size of microorganisms is that the surface area/ volume ratio limits the size of bacteria to microscopic dimension

Shape and arrangement:-

 the shape of the bacterium is governed by its rigid cell wall.
 rigid material determines that cell will have a particular shape is not yet understood.
typical bacterial cell of spherical{cocci}, straight roads {bacilli}, rods that are helically curved {spirilla},some are pleomorphic  i.e., that can exhibit a variety of shapes.
Bacterial cell reveals various component  structures some of these are external to the cell wall others are internal to the cell wall

Gram staining:-

A banish scholar, Christian gram in 1884 devised  a differential staining procedure, which differentiates between two kinds of bacteria Gram Negative and Gram Positive Bacteria.
A thin smear of the bacterium is prepared on the side and it can be heated fixed
 to the smear Crystal Violet solution is applied for 30 seconds
 the slide is then gently rinsed in clean water, and Iodine solution is applied for 30 seconds, then gently Rinsed  in clean water
95% ethyl alcohol is applied and this is renewed till all the thickness parts of the smear have ceased to give off the dye.
This is usually takes from 20 seconds to 1 minute
 Gram Positive Bacteria returned the violet colour iodine combination {retaining of blue purple colour even after alcohol wash}
Gram Negative Bacteria is purple colour of the alcohol wash and it will show red colour with saffron

Cell wall of Gram Positive Bacteria:-

Gram Positive Bacteria as usually have your much greater amount of peptidoglycon  in the cell wall.
Walls of Streptococcus pyrogens contains polysaccharides that are covalently linked to  peptidoglycon and can be extracted with hot dilute HCl.
the walls of Streptococcus aureus and Streptococcus faecalis contain tcichoic acid which are covalently  linked to  peptidoglycon and which can be extracted with cold dilute HCl.
teichoic acid bind magnesium ions and there’s some evidence that they help to protect bacteria from thermal injury.
The wall of Gram Positive Bacteria contain very little lipids, but most of the microbacterium rich in lipids.
cellwall of gram positive bacteria,+ve bacteria
cellwall of gram positive bacteria

Cell wall of Gram Negative bacteria:-

The wall of Gram Negative bacteria are more complex than those of Gram Positive Bacteria
presence of outer membrane That surrounds a thin  underline of peptidoglycon. because of this membrane the wall of Gram Negative bacteria are rich in lipids
this outer membrane serves as an impermeable barrier to prevent the escape of important enzymes such as those involved in cellwall growth,from the space between cytoplasmic membrane and outer membrane
the outer Membrane of Gram Negative cell wall is anchored to the underline  peptidoglycon by means baruslipoprotein
the membrane is bilayered structure consiststing mainly of phospholipids, proteins and lipopolysaccharides
The LPS has toxic properties and  is also known as endotoxic


some bacterial cell are surrounded by a viscous substance forming a covering layer {or} envelope around the cellwall
if this layer can be visualised by light microscopy using special staining methods, it is termed as capsule
Is the layer is too thin to be seen by light microscope it is termed as microcapsule
If it is so abundant that many cells are embedded in a common Matrix, the materials is called slime
Capsule provide protection against temporary drying by binding water molecules
They may block attachments of bacteriophages
They inhibit the engulfment of pathogenic bacteria by WBC
They may promote attachment of bacteria to surfaces
capsules are composed of polysaccharides and also single kind of sugar are termed as homopolysaccharides
other capsules are composed of several kinds of sugar are termed as a heteropolysaccharides
cellwall of gram negative bacteria,-ve bacteria
cellwall of gram negative bacteria


Bacterial flagella are hair like helical appendages that provide through the cell wall and are responsible for swimming motility
Their location on the cell varies depending on the bacterial species and maybe polar {or} lateral
I flagellum  is composed of three parts – a basal body associated with the cytoplasmic membrane and cell wall ,a short hook and helical filament which is as usually several times as long as the cell
The chemical composition of the basal body is the unknown but the hook and the filament are composed of protein subunits arranged in a helical fashion
The protein of filament is known as flagellin
Bacteria having polar flagella swim in a back and Foarth direction, they reverse the direction of swimming by reserving the direction of flagellar rotation

flagella,flagella rotation,flagellamoment

Pili {fimbriae}

Pili arehallow,non- helical filamentous appendages that thinner, shorter and more numerous then flagella
They don’t function in motality since they count  on non motile as well as motile species
One type known as F- pilus {sex pilus} serves  as the part of entry of genetic material during bacterial mating
Some pili  play a major role in human infection by allowing pathogenic bacterium to attach epithelial cells lining the respiratory, intestinal {or }genitourinary track


These structures are unique to bacteria
they are thickwalled highly refractile bodies that are produced by bacillus, clostridium,sporosarcina
The shapes of  endospores and also their location within the vegetative cell varying depending on the species
The structural changes that occur during the development of endosperm have been extensively studied in bacillus and clostridium species
endosperm are usually produced by cells growing in rich media but which are approaching the end of active growth
Endospores are extremely resistant to dessication, staining disinfecting Chemicals, radiation and heat
The endospores of clostridium botulinium type-a  have been reported to resist for boiling for several hours
most of The endospores  can resist treatment at 800c for 10 minutesall endosopres contain large amounts dipicolinic acid DPA
the calcium DPA complex may possibly play a role in the heat resistant of endospore
syn. Of DPA and uptake of complex calcium occurs during advanced stages of sporulation
during germination endospores looses their resistant to heat and staining


plasmids are  extra-chromosomal replicating small circular ds DNA ,covalent molecule found in most of bacterial species

characteristic features of plasmids:-

They are extra-chromosomal and replicate indefinitely
the plasmids  are circular DS DNA, that is not essential for the growth of the cells but they may carry the genes that give resistance to antibiotics, these acts as marker molecule
plasmids are low molecular weight and easily isolated
They have single recognition site for a number of restriction enzymes.
Plasmids are present in large copies in a cell and are composed to a daughter cell during cell division
Plasmids  are divided into two groups based on the presence {or} absence of transgenic genes.

 conjugative plasmids:-

these placements mediate the transfer of genome by conjugation
they contain transfer genes [trans-gene] and mobilizing which are present in the plasma

non conjugative plasmid:-

these plasmids cannot transfer the genes from one bacteria to another bacteria because of the antibiotic of transferredgene
 a number of plasmids in a cell is referred to as copy number
if they process more number of copies is referred to as a high copy number of plasmids

Classification  it is based on the genes coded on it. it is of 3 types:-

F -plasmid
R –plasmid
Col -plasmids

F- plasmid :-

they carry the transfer gene and have the ability to transfer the gene through the conjugation
if  the F – factor  is present on it then it is referred to as F- positive when it lacks F – factor regarded as  F-negative
F – factor converts the f negative into positive

R- plasmid:-

these plasmid contain the genes for antibiotic resistance due to the presence of antibiotic resistance genes they can survive when they present in corresponding antibiotic

col- plasmid:-

contains colesinogenic factor that have colesin is synthesized from col- plasmid, which is the bactericidal it kills the bacteria.
example PBR322

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