Bacteria are single-celled microorganisms that can exist in three basic shapes - rods (called bacilli), spheres (called cocci), or spirals. They reproduce through binary fission and consume nutrients in various ways. Bacteria are classified based on several factors including their shape, staining properties, oxygen requirements, environment, and cell wall composition. Some key groups of bacteria include phototrophic bacteria, gliding bacteria, sheathed bacteria, and spirochetes.

1. BACTERIA
Zulcaif Ahmad

2. CONTENT
 History of Bacteria.
 Introduction of bacteria.
 Ways of classification.
 Groups of Bacteria.
 Comparison b/w Prokaryotes & Eukaryotes.
 Comparison with other Kingdoms.

3. Introduction to Bacteria

4. What are bacteria?
• Single celled organisms
• Very small E. Coli O157:H7 can
make you very sick
• Need a microscope to see
.•Can be found on most materials
and surfaces
Streptococcus
• Billions on and in your can cause strep
throat.
body right now
This E. coli helps you
digest food.

5. What do they look like?
Bacilli
• Three basic shapes
– Rod shaped called bacilli
– (buh-sill-eye)
– Round shaped called cocci
Cocci
– (cox-eye)
– Spiral shaped
• Some exist as single cells,
others
cluster together Spiral
Cluster of cocci

6. Bacteria are ALIVE!
• What does it mean to be
alive?
-They reproduce
(make more of
themselves)
- They need to eat

7. How do bacteria
reproduce?
• Grow in number not in size
– Humans grow in size from child to adult
• Make copies of themselves by dividing in half
– Human parents create a child

8. How do bacteria eat?
• Some make their own food from Photosynthetic
sunlight—like plants bacteria
• Some are scavengers
– Share the environment around them
• Example: The bacteria in your stomach are now
eating what you ate for breakfast
Harmless bacteria on
the stomach lining
• Some are warriors (pathogens)
– They attack other living things
• Example: The bacteria on your face can attack skin
E. Coli
causing infection and acne O157:H7
is a pathogen

9. BRIEF HISTORY:
In a 1683 letter to the Royal
Society
Of London, Anton van
Leeuwenhoek
Described microscopic
“STREAKS &
THREADS”, among his tiny
animals.
The streaks and threads
remained nameless until
1773,

10. In 1773, when the Danish
scientist
Otto Frederick Muller
christened them bacilli.
Bacilli is the plural form
of the Latin word Bacillus
meaning but not all
“bacilli” were rods. Some
were spiral and some
were circular, & “bacilli”
would not do.

11. Therefore, in the 1850s, The
French investigator Casimir
Davaine began calling a
microscopic creatures
“BACTERIA”, even though this
derivatives of the Greek
bacterion also means rod. In
the next few decades
“bacteria” came to refer to all
the micro-organisms in that
group, and the word “Bcillus”
was reserved for rod forms
only.

12. Archaebacteria vs Eubacteria
Archaebacteria
Archaebacteria have prokaryotic
cells, which means they don't have
a nucleus. While they usually live in
groups, they are considered
unicellular, meaning they have one
cell. Archaebacteria can make their
own food, making them autotrophs.
They can live in hot springs, deep
ocean vents with no light and under
extreme pressure, and in very salty
lakes.. so basically, all extreme
environments. Some of them can
even live with no oxygen

13. Eubacteria
Eubacteria:
are a group of
unicellular organisms
and are similar to
archae in not having
cell nucleus or
organelles.

14. Comparison chart
Archaebacteria Eubacteria
Cell Membrane: Branched chain ether Straight chain ester
linked lipids. linked lipids.
tRNA: Lacks thymine in tRNA. Thymine present in
tRNA.
RNA polymerase: Ten subunit RNA 4 subunit RNA
polymerase core. polymerase core.
Role in ecology: Role in bio-geochemical Vital in nutrient recycling.
cycles is unexplored.

15. DNA: DNA is closer to DNA differs from
eukaryotes (sent on eukaryotes.
to daughter cells via
mitosis)
Definition: Single celled organisms All true bacteria or group
without anycell of unicellular prokaryotic
organelles or nucleus. microorganisms.
Morphology: Occur in various shapes Various shaped bacteria
like spheres, rods, plates have been identified like
and spirals. rods, cocci, spirals,
comma shaped, tightly
coiled etc.
Cell Wall: Lacks peptidoglycan. Peptidoglycan is present.
Extremophilic: Yes. Some.

16. WAYS OF CLASSIFICATION
Bacterial Classification Based
on Shapes
Rod shaped bacteria's are
also called Bacilli
e.g. E.coli

17. Spherical-shaped bacteria
Spherical-shaped bacteria are
called cocci
e.g.
Staphylococcus and
Streptococcus

18. Spiral-shaped bacteria
Spiral-shaped bacteria are
called
spirilla
e.g.
Treponema

19. Bacterial Classification Based on
Staining Methods
Bacteria are grouped as 'Gram
positive' and 'Gram negative'
bacteria, based on the results of
Gram staining method, wherein an
agent is used to bind to the cell wall
of the bacteria.
Gram positive bacteria - take up
crystal violet dye and retain their
blue or violet color.
Gram negative bacteria - do not take
up crystal violet dye, and thus
appear red or pink.

20. Bacteria are also classified based on the
requirement of oxygen for their survival
Anaerobic bacteria
Aerobic bacteria
Bacteria that do not require oxygen for
Bacteria that need oxygen for survival.
their survival Anaerobic bacteria cannot bear oxygen and
may die if kept in an oxygenated
environment. Such types of bacteria are
usually found in places like, under the surface
of the Earth, deep oceans, and bacteria
which live in some medium.

21. Autotrophic and Heterotrophic Bacteria
Autotrophic bacteria (also known as
autotrophs) obtain the carbon it requires
from carbon dioxide
Some autotrophs directly use sunlight in Heterotrophic bacteria obtain sugar from
order to produce sugars from the environment they are in (for example,
carbondioxide whereas, others depend the living cells or organisms they are in).
on various chemical reactions. E.g. bacillus anthracia
e.g. cyanobacteria

22. Bacterial Classification Based on Environment
• Mesophiles - which require moderate conditions to survive.
• Extremophiles - which can survive in extreme conditions.
• Acidophiles - which can tolerate low pH conditions.
• Alkaliphiles - which can tolerate high pH conditions.
• Thermophiles - which can resist high temperature.
• Psychrophilic bacteria - which can survive extremely cold
conditions.
• Halophiles - which can survive in highly saline conditions.
• Osmophiles - which can survive in high sugar osmotic
conditions.

23. Classification of bacteria
Bacteria are arranged into 19 groups

24. 1. Phototrophic bacteria
• Cell shapes :
spherical,rod,vibrio,or
spiral.
• Gram negative
• Habitat : aquatic
environment
Example : rhodospirillum species

25. 2.Gliding bacteria
• Cell shapes :
rod,spherical,or
filamentous.
• Gram negative
• Habitat : soil, decomposing
plant material, aquatic
environment
Example: stigmatella

26. 3.Sheathed bacteria
• Cell shapes : rod or
filamentous.
• Gram negative.
• Habitat: aquatic
environment, sludge.
Example: lepiothrix

27. 4.Budding /Appendaged bacteria
• Cell shapes:
spherical,oval,bean,rod
with pointed ends, some
exhibit hyphal growth
(filaments )
• Habitat: soil, aquatic
environment .
Example: caulobacter

28. 5. Spirochetes
• Cell shape :
slender,
helically
coiled(spiral).
• Most of them
are gram
negative Example : spirochaeta

29. 6.Spiral and Curved bacteria
• Cell shape: helically coiled
rods , some with one or
more complete turns.
• Gram negative
• Habitat : aquatic,
reproductive organs,
intestinal tract and oral
cavity of animals (including
humans)
Example :vibrio species

30. 7.Gram negative aerobic rods and
cocci
• Cell shape : rod, oval ,
spherical.
• Gram negative
• Habitat : soil and
aquatic environment ,
salt brines .
Example: brucella
species

31. 8.Gram negative facultative anaerobic
rods
• Cell shape : typically ,
short rod
• Gram negative
• Habitat: aquatic
environment, soil,
urine, faeces
Example : E.coli

32. 9.Gram negative anaerobic rods
• Cell shape : rod , straight
or curved , exhibiting
considerably
polymorphism
• Habitat: natural cavities
of
humans and other Example :bacteroides
animals also intestinal
tracts of insects.

33. 10.Gram negative cocci and
coccobacilli
• Cell shape : cocci in pairs
(diplococci )some coccobacilli
occur single and in pairs
• Gram negative
• Habitat : on mucous
membrane of humans and
other animals
Example : neisseria
gonorrhoaea

34. 11.Gram negative anaerobic cocci
• Cell shape: very small to very
large spherical cell in pairs ,
masses, or chains,
• Habitat : respiratory and
intestinal tracts of human and
other animals
Example :veillonella

35. 12. Gram negative chemolithotrophic
bacteria
• Cell shape : spherical,
rod , spiral,
multilayered
membranes in some
species
• Gram negative
• Habitat : soil, sewage ,
aquatic environments ,
natural environment
with large amount of
Example: nitrosomonas
sulphur , iron or
manganese

36. 13.Methane producing bacteria
• Cell shape : spherical , rod
spiral
• Gram positive or gram
negative
• Habitat: gastrointestinal
tract of animals , aquatic
and sewage
Example:
methanospirillum

37. 14. Gram positive cocci
• Cell shape : cocci occurring singly or
in pairs , chains or clusters
• Gram positive
• Habitat: soil , fresh water , skin and
mucous membrane of warm
blooded animals including human
Example :
streptococcus

38. 15. Endospore forming rods and cocci
• Cell shape; rods
• Gram positive
• Habitat :soil , air , aquatic,
intestinal tracts of animals
Example : bacillus

39. 16.Gram positive asporogenous , rod
shaped
• Cell shape: bacilli occurring
singly or in chains
• Gram positive
• Habitat ; dairy products ,
grains and meat products ,
water, sewage , oral cavity
and vagina
Example : lactobacillus

40. 17.Actinomycetes and related
organisms
• Cell shape: irregular
rod shaped ,
filaments and
branched filaments
• Gram positive
• Habitat: soil , aquatic ,
air and animals
mycobacterium tuberculosis .

41. 18.The Rickettsias
• Cell shape : short rods or
ovals , often pleomorphic
• Gram negative
• Habitat: insect carriers , birds
and mammals
Example: rickettsia akari

42. 19. The Mycoplasmas
• Cell shape: lack true cell wall ,
highly pleomorphic
• Gram negative
• Habitat : mucous membrane
of respiratory tract , and lower
enital tract
Example: mycoplasma
pneumoniae

43. Differences between prokaryotes and
eukaryotes

45. How six kingdoms differ from each
other ?

46. References
• Concise & Conceptual Microbiology
( First edition volume one by Dr Tariq Javed)
( Section 2)
http://www.google.com.pk/imgres?imgurl=http://images.tutorvista.com/content/cell-
structure/comparisonof-prokaryotic-cells-and-eukaryotic-
cells.gif&imgrefurl=http://www.tutorvista.com/content/biology/biology-i/cell-
structure/prokaryotic-eukaryotic-
cells.php&h=248&w=529&sz=6&tbnid=7nQkJJDEIg15mM:&tbnh=62&tbnw=132&prev=/searc
h%3Fq%3Ddifference%2Bbetween%2Bprokaryotes%2Band%2Beukaryotes%26tbm%3Disch
%26tbo%3Du&zoom=1&q=difference+between+prokaryotes+and+eukaryotes&usg=__-
RcCUDdWGwzy4qHCfeFZ0gjyDR8=&docid=tHNWfgpf6HoBKM&hl=en&sa=X&ei=qdPSUOmoE
6r-2QX59IDoBA&sqi=2&ved=0CC4Q9QEwAA&dur=726

47. • http://www.diffen.com/difference/Archaebac
teria_vs_Eubacteria
• http://www.ucmp.berkeley.edu/bacteria/bact
eria.html