Topic of this presentation is Kingdom Monera Biological Classification Part 2.
Bacteria are the sole members of kingdom Monera.
These are most abundant microbes.
Monerans show most extensive metabolic diversity
being autotrophic, chemoautotrophic, decomposers and parasitic.
So in this way, we see ample diversity in Kingdom Monera.
Here we have shown various types of bacteria
based on their shapes
as you see these small spherical forms
these are called "cocci"
singular is "coocus"
plural is "cocci"
capsule shaped bacteria are called "bacilli"
singular is "bacillus"
for example Lactobacillus
Now you know the shape of baceria only by knowing it's name
Spirilla are the spiral shaped bacteria
And comma shaped bacteria are called Vibrio
We divide Kingdom Monera in 3 categories
Archaebacteria, Eubacteria and Mycoplasma
Archaebacteria are the ancient forms of bacteria
Bacteria we usually talk about and cyanobacteria are included in the category Eubacteria
Here, we want to tell our students that blue green algae is a misnomer
blue green algae is a bacteria and it is photosynthetic bacteria
It is called Cyanobacteria
Mycoplasma is a wall-less bacteria i.e. it lacks cellwall
Now we will discuss types of nutrition occur in bacteria
Basically two types of nutrition are seen in bacteria - autotrophic and heterotrophic
Autotrophic forms synthesize food on their own
while heterotrophic forms derive energy from other living organisms.
Autotrophic forms can be further divided into photoautotrophic and chemoautotrophic forms.
photoautotrophic forms utilize solar energy to synthesize their food
Chemoautotrophic forms utilize the energy of some exothermic reactions to prepare their food.
exothermic reactions are the reactions where heat is released
So these Chemoautotrophic forms utilize energy released during exothermic reactions  to prepare their food.
three forms of heterotrophic bacteria are - saprotrophic, parasitic and symbiotic
Rhizobium (bacteria) forms a symbiotic association with roots of leguminous plants.
Saprophytic bacteria digest food outside their body
These forms release digestive enzymes
which digest the food outside the body and convert it into liquid form
Such digested liquid food (sap) is then absorbed by the bacteria
such organisms are called Saprophytic
Now we will discuss about Photoautotrophic Bacteria
Photosynthetic pigment is bacteriochlorophyll.
bacteriochlorophyll differs from the chlorophyll that occurs in green plants
No oxygen is evolved in bacterial photosynthesis.
This point is very important if you are preparing for some competitive exam or interview.
oxygen is evolved during photosynthesis in green plants.
But in Photoautotrophic Bacteria, anoxygenic photosynthesis occurs
anoxygenic photosynthesis occurs in Green sulphur bacteria (Chlorobium)
Here we have mentioned the equation of photosynthesis that occurs in these bacteria
This bacteria uses hydrogen sulphide instead of water
Photosynthetic pigment is bacteriochlorophyll.
It utilizes solar energy to synthesize carbohydrate and sulphur
As they use hydrogen sulphide therefore sulphur is formed during photosynthesis instead of oxygen
Now we will discuss about Chemoautotrophic Bacteria
These bacteria derive energy from exothermic reactions which is utilised in manufacturing of food.
Example: Nitrogen fixing bacteria (Nitrosomonas, Nitrosococcus and Nitrobacter)
These examples are very important if you are preparing for some competitive exam or interview.
Here we have mentioned a very important note that
Chemosynthetic autotrophs play very important role in
recycling nutrients like nitrogen, phosphorous, iron and sulphur.
Now we will discuss about Saprophytic Bacteria
They are called nature's scavengers.
As they clean the environment by decomposing dead organisms.
And release the trapped nutrients into soil which are then utilized by plants
In this way Saprophytic Bacteria are nature's scavengers.
Aerobic breakdown of organic compounds is called decay or decomposition.
Anaerobic breakdown of carbohydrates is called fermentation.
Example: Production of alcohol, preparation of curd, cheese and other dairy products.
Aerobic breakdown of organic compounds is called decay or decomposition.
Anaerobic breakdown of carbohydrates is called fermentation.
Anaerobic breakdown of proteins is called putrefaction.
Example: Food poisoning.
Now we will discuss this topic - Oil Spillage
A marine oil spill is the release of a petroleum into the marine ecosystem, due to human activity.
This oil spillage is very detrimental to marine ecosystem
and harms marine life in various ways
These are the traces of oil spills
This oil spreads to cover a vast area
The marine organisms under that area
are badly affected
Recall that the atmospheric oxygen dissolves in water
and the organisms under water surface utilize this oxygen
In this way the supply of oxygen is cut off due to a layer of petroleum over water surface
Latest use of saprophytic bacteria is in bio degradation of organic pollutants like petroleum spillage.
Example: Pseudomonas.
Pseudomonas digests the oil spillage
And reduces the harmful effects of petroleum
Pseudomonas is very important example if you are preparing for competition
Now we will talk about Symbiotic Bacteria
Rhizobium is a nitrogen fixing bacteria that lives in root nodules of leguminous plants.
All plants that give us pulses like gram, pea, moong etc. are called leguminous plants.
second example is of Escherichia coli
Escherichia coli lives in human intestine.
It feeds on undigested matter, checks growth of putrefying bacteria and produces vitamins B and K.
This example is very important if you are preparing for some competition.
It feeds on undigested matter, checks growth of putrefying bacteria
As these bacteria compete with harmful bacteria and check their growth in gut.
In this way E. coli. lives symbiotically in human intestine.
Here we have shown the flowchart of modes of reproduction occur in bacteria
Basically two modes of reproduction are seen - asexual and sexual
Binary fission and sporulation are asexual forms of reproduction.
gamete formation does not occur in sexual reproduction
We witness different kind of incidence called conjugation
The process of formation of spores is called sporulation.
Sporulation occurs in adverse conditions
adverse conditions like high temperature, scarcity of water and food
These bacteria form endospores during such adverse conditions
endospores have thick resistant wall
to withstand any kind of extreme adverse conditions.
Living organism survives through adverse condition inside the spore.
On arrival of the favourable conditions,
thick wall of spore splits to release the living organism
In this way sporulation helps bacteria surviving through the adverse conditions.
We have mentioned important points related to sporulation process
we have just discussed with the help of diagram
Use these point for your note making
Here we have mentioned one very important point
if you are preparing for competition
Here we have mentioned name of two bacteria
in which the process of sporulation occurs
Clostridium tetani and Bacillus anthracis
Clostridium tetani  causes tetanus and is very harmful bacteria
and Bacillus anthracis causes anthrax - a life threatening disease
Both the bacteria are very harmful and life threatening
Both the bacteria form spores and thus are very detrimental
These bacterial spores cannot be killed just by boiling water
In this way these bacteria are very harmful
We would like to tell some daily life related facts about tetanus bacteria
You must have known that tetanus vaccine is given if a person is hurt with rusted object
Rusted object signifies that it is old and unused for a long time
there is a possibility that this object has deposition of tetanus bacteria
If a person is hurt with such an object and spores enter his body
then these spores will germinate to cause tetanus.
That's why, it is said that if someone is hurt with rusted object, tetanus vaccine is a must.
On the other hand, if someone is hurt with a clean object which is used in routine
for example the knife we use in our kitchen
then we don't need to worry
because that knife is washed daily
therefore there is little possibility that this knife has deposition of spores.
In this way, if we connect biology with our daily life  then it becomes interesting as well useful.
We will now discuss in brief about Biological Warfare or Germ Warfare
Biological warfare is the use of biological toxins or infectious agents
such as bacteria, viruses, and fungi with the intent to kill humans, animals or plants as an act of war.
Anthrax is one of the most potential biological weapons in the world.
There are many historical records where Anthrax bacteria is used as biological warfare.
When we use bacteria with such detrimental intentions then the bacteria is called biological weapon.
We are discussing all these points to strengthen your concepts of biology.
We will now discuss the process of Conjugation in brief.
We already know that  bacteria is a prokryotic organism.
And it has a circular DNA
But some bacteria has a small ring of DNA along with circular DNA
It is called plasmid
Plasmids carry special genes which confer some useful traits to the organism
like resistance to certain antibiotics or toxins.
If antibiotic resistant gene is present on plasmid
Then this bacteria remains unaffected from effects of that particular antibiotic
If other bacteria of the same species doesn't have this plasmid
then this bacteria which has a plasmid can donate one copy of this plasmid to the other one which lacks this plasimd
plasmid is self-replicating, hensce bacteria produces a copy of plasmid and donates it to the other one
through a tube like structure called pilus
the bacteria which has plasmid also has this pilus
so with the help of this pilus donor bacterium connects with recipient bacterium.
In this way, this bacterium too becomes antibiotic resistant.
And this process is called conjugation
Archaebacteria are the most primitive prokaryotes
These bacteria can survive extreme conditions
These bacteria have special type of cell wall
structure of their These bacteria is very unique
this feature (unique cell wall) is responsible for their survival in extreme conditions.
There are 3 types of Archaebacteria - Methanogens, Thermoacidophiles and Halophiles
we will discuss ahead features of these bacteria in brief.
Methanogens are methane producing anaerobic bacteria.
Methanogens are present in the gut of several ruminant animals (e.g. cows and buffaloes)
munching or cud chewing animals are called ruminants
ruminants have 4 chambered stomach.
Methanogens are found in "rumen" and reticulum - two chambers of the stomach.
These bacteria help in cellulose digestion
And produce methane gas.
Methanobacterium and Methanococcus are methanogen bacteria.
These methanogens occur in biogas plants also.
Thermoacidophiles live in hot sulphur springs.
A natural hot spring is shown here in the diagram
Water vapors can be seen as the water is too hot.
Thermoacidophiles have ability to tolerate high temperature as well as acidity.
And Halophiles occur in salt rich areas
'Halo' indicates salt and 'phile' means loving
Therefore Halophiles are salt loving bacteria
These occur in salt rich areas such as sea beds and salt marshes.
Now we will discuss some points related to Cyanobacteria
Cyanobacteria  is also known as Blue- Green Algae
These have chlorophyll a similar to green plants and perform oxygenic photosynthesis.
If you are preparing for some competition the such point are very important.
As these bacteria have  chlorophyll a, they perform oxygenic photosynthesis.
They produce oxygen during photosynthesis
Some of these can fix atmospheric nitrogen
Nostoc, Anabaena etc. are examples of such bacteria
Diagram of Nostoc is shown here
These nitrogen fixing bacteria have specialised cells called heterocysts
heterocysts  are shown here
Heterocysts  are large sized, thick walled cells.
Thick wall is impermeable to oxygen but permeable to nitrogen.
Thus heterocysts create anaerobic environment which is suitable for nitrogen fixation.
Heterocysts have enzyme nitrogenase which plays very important role in nitrogen fixation.
nitrogen fixation process requires anaerobic environment
Thus heterocysts provide anaerobic condition for functioning of nitrogenase enzyme.
Now we will discuss some points of difference between bacteria and cyanobacteria.
firstly,  Bacteriochlorophyll is the photosynthetic pigment in bacteria
whereas Cyanobacteria has Chlorophyll a similar to that occur in plants.
Photosynthesis is anoxygenic in bacteria
whereas photosynthesis is oxygenic in Cyanobacteria
These points of difference are very important
Now we will discuss some points related to Mycoplasma
Mycoplasma is also known as PPLO- Pleuropneumonia Like Organisms
This is a pneumonia causing bacteria.
Mycoplasma are the simplest and smallest prokaryotes without cell wall.
We will now discuss Gram Staining Technique in brief.
This staining technique was introduced by Danish Bacteriologist Hans Christian Gram in 1884.
This test differentiate the bacteria into Gram Positive and Gram Negative Bacteria,
which helps in the classification and differentiations of microorganisms.
The differences in cell wall composition of Gram positive and Gram negative bacteria
accounts for the Gram staining differences.
Gram positive bacteria retain the stain
whereas Gram (-) bacteria do not retain the stain
The differences in cell wall composition accounts for the Gram staining differences.
Here we have compared cell walls of gram positive and gram negative bacteria.
The cell walls of gram positive bacteria have a thick layer of peptidoglycan
and lipid content is low.
If you study gram positive bacteria
then it has a thick layer of peptidoglycan and lipid content is low
whereas gram negative bacteria has thin layer of peptidoglycan
and thick outer layer which is formed of lipids
This is the thick layer of lipid
And this is the cell membrane below the layer of peptidoglycans
Thus gram negative bacteria has less peptidoglycans and more lipid content.
now we will discuss significance of this difference in cell walls
Now we will discuss procedure of staining technique with the help of this diagram.
Gram positive and negative bacteria are shown here.
These bacteria are colorless
First of all these bacteria are treated with crystal violet
Both types of bacteria pick this stain
Then we treat these bacteria with iodine
color will change a bit
Last step is decolorization
we treat bacteria with absolute alcohol
absolute alcohol dissolves the lipids in the cell walls
recall the structure of cell walls we have just discussed
gram negative bacteria has high content of lipids
that dissolves in absolute alcohol
and will form large holes in the cell wall
the stain particles will come out from those large holes
That's why these bacteria will loose the color and become colorless
It  means this bacteria is not able to retain the stain.
Whereas this gram positive bacteria a thick layer of peptidoglycan and lipid content is low.
Therfore absolute alcohol does not form large holes in its cell wall
And color is reatained by gram positive bacteria.
As a result when we observe these bacteria under microscope after decolorization step
we can see colored bacteria
Whereas gram negative bacteria are seen colorless.
In this way this staining technique differentiates bacteria into two categories.
Gram positive and Gram negative
Here we have mentioned principle of staining technique
We have already discussed all points related to this concept
you can use these points for notes
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