this is the overall information about the bacterial cell organization and ultra structure of bacteria and types of bacteria on the basis of cell wall. structure of bacterial plasmid and types of bacterial plasmid

1. Submitted by- Nidhi Gossai Submitted to -
Msc IM NEHA MAM
1st Sem

3. Bacterial cell
Morphology Arrangement
1. Size and Shape 1. Coccus
2.Structure 2. Bacillus
i. Capsule 3. Spirillus
ii. Flagella 4. Other forms
iii. Pilli & Fimbriae i. Pleomorphic
iv. Cell wall ii. Trichome
v. Cytoplasm iii. Palisade
a.Nucleoids iv. Hyphae
b. Plasmid
c. Cell component
vi. Endospore

4. Bacterial Size and Shape
 The size, shape and arrangement of microbial cells vary with species to which
they belong.
 Most bacterial cells range in size from 0.2 to 10 microns
 Thiomargarita namibiensis is world’s largest bacteria , a gram- negative
Proteobacterium found in the ocean sediments off the coast of Namibia
 Mycoplasma genitalium a parasitic bacterium which lives in the Primate
bladder waste disposal organs genital and respiratory tracts is a smallest
bacteria.
 Antony Van Leeuwenhoek first observed bacteria through a microscope
and called them Animalcule.
 He is also known as FATHER OF MICROBIOLOGY and bacteriology.
 Ehrenberg 1829 coined the term Bacteria.

5. COCCUS
. Cocci (s., coccus) are roughly spherical cells. They can
exist singly or can be associated in characteristic
arrangements that can be useful in their identification.
Diplococci (s., diplococcus) arise when cocci divide and
remain together to form pairs. Long chains of cocci
result when cells adhere after repeated divisions in one
plane; this pattern is seen in the genera Streptococcus,
Enterococcus, and Lactococcus

6. B. megaterium-rods in chains
comma-shaped vibrios
BACILLUS
Bacillus megaterium is an example of a bacterium with a rod shape
Forms of bacillus
Monobacillus
Diplobacillus
Streptobacillus
Vibrios are comma-shaped
Spirochetes are flexible, spiral-shaped bacteria
that have a unique, internal flagellar
arrangement
Other bacteria are pleomorphic, being
variable in shape and lacking a single,
characteristic form
VIBRIO

7. BACTERIAL CELL
FlagellumInclusionChromosome (DNA)Fimbriae

9. Bacterial cell membrane
The Fluid Mosaic Model of Bacterial Membrane Structure.
The cell envelope is defined as the
plasma membrane and all the
surrounding layers external to it. The
cell envelopes of many bacteria consist
of the plasma membrane, cell wall, and
at least one additional layer (e.g.,
capsule or slime layer). Of all these
layers.
Plasma membrane is the most
important because it encompasses the
cytoplasm and defines the cell. If it is
removed, the cell's contents spill into
the environment and the cell no longer
exists.

10. CELL WALL
The cell wall is the layer that lies just outside
the plasma membrane.
It helps maintain cell shape and protect
the cell from osmotic lysis
It can protect the cell from toxic
substances
After Christian Gram developed the Gram stain in 1884, it
soon became evident that most bacteria could be divided
into two major groups based on their response to the
Gram-staining procedure.
Gram-positive bacteria stained purple, whereas Gram
negative bacteria were pink or red.

11. Peptidoglycan structure
Peptidoglycan is composed of many identical
subunits. Each subunit within the sacculus
contains two sugar derivatives
N-acetylglucosamine (NAG) and N-acetylmuramic acid
(NAM), and several different amino acids
The amino acids form a short peptide consisting of
four alternating D- and L-amino acids
the peptide is connected to the carboxyl group of NAM
The backbone of each strand is composed of
alternating NAG & NAM residues
Many bacteria cross-link the strands by connecting the
D-alanine to diaminopimelic acid of the other strand
Other bacteria use a peptide interbridge instead .
The peptidoglycan sacculus is strong but elastic. It is able to
stretch and contract in response to osmotic pressure this is
due to the rigidity of the backbone coupled with the flexibility
of the cross links

12. Gram Positive Cell Wall
Most bacteria that stain Gram positive belong to
the phyla Firmicutes and Actinobacteria, and
most of these bacteria have thick cell walls
composed of peptidoglycan and large amounts of
other polymers such as teichoic acids
Teichoic acids are polymers of glycerol or
ribitol joined by phosphate groups

13. Gram negative cell wall
LPS has many important
functions. (1) It contributes
to the negative charge on
the bacterial surface
because the core
polysaccharide usually
contains charged sugars and
phosphate
(2) It helps stabilize outer
membrane structure
because lipid A is a major
constituent of the exterior
leaflet of the outer
membrane.
(3) It helps create a
permeability barrier

14. Flagella
Bacterial flagella are slender, rigid structures about
20 nm across and up to 20 11m long.
Monotrichous bacteria (trichous means hair) have
one flagellum; if it is located at an end, it is said to
be a polar flagellum
Amphitrichous bacteria (amphi means on both
sides) have a single flagellum at each pole.
lophotrichous bacteria (lopho means tuft) have a
cluster of flagella at one or both ends
Flagella are spread evenly over the whole surface of
peritrichous (peri means around) bacteria
Bacterial flagellum is composed of three parts
(1) The longest and most obvious portion is the
filament, which extends from the cell surface to the tip.
(2) The basal body is embedded in the cell envelope (3) a short, curved segment, the hook, links the
filament to its basal body and acts as a flexible
coupling.

15. Bacterial Plasmid
 During 1950 working on conjugation process it was found that maleness in
bacteria is determined by a transmissible genetic element. When male and female
bacteria conjugate, every female is converted into a male. This inherited property
of male is called F factor which is transmitted by cell to cell contact. Therefore F is
a separate genetic element. 1952 J. Lederberg coined the term plasmid as a
genetic name for this element. Hence plasmid may be defined as a Small circular
self replicating and double stranded DNA molecule present in bacterial cell in
addition to its chromosome. It replicates independently during cell division and
inherited by both of daughter cells. Therefore, its function is not governed by the
bacterial chromosome.
 Types of plasmid
 Sex factor or fertility F factor
 R (resistance) plasmid
 Col plasmid
 Ti plasmid
 Ri plasmid

16. Bacterial Endospore
Bacterial only produced by certain members of the
genera Bacillus and Clostridium (rods), and
Sporosarcina (cocci) within the phylum Firmicutes.
endospores are extraordinarily resistant to
environmental stresses such as heat, ultraviolet radiation,
gamma radiation, chemical disinfectants, and desiccation.
The spore consists of a core surrounded by several layers
that vary significantly in composition.
The core has normal cell structures such as ribosomes and
a nucleoid but has very low water content
The spore coat protects the spore from chemicals and
various lytic enzymes such as lysozyme.
The inner membrane is extremely impermeable to various chemicals,
including those that cause DNA damage. The core has very low water
content, high amounts of dipicolinic acid complexed with calcium ions
(CaDPA), and a slightly lower pH, all of which contribute to the spore's
resistance to harsh conditions.

17. Sporulation
Sporulation may be divided into seven
stages. The cell's DNA is replicated
(stage I), followed by an inward folding
of the cell membrane to enclose part of
the DNA and produce the forespore
septum (stage II). The mother cell
membrane continues to grow and
engulfs the immature endospore in a
second membrane (stage III). Next,
cortex is laid down in the space
between the two membranes, and both
calcium and dipicolinic acid are
accumulated (stage IV). Protein coats
are formed around the cortex (stage V),
and maturation of the endospore
occurs (stage VI). Finally, lytic enzymes
destroy the sporangium, releasing the
spore (stage VII). Sporulation requires
about 10 hours in Bacillus megaterium.
0 Bacterial Spore Formation