A presentation on bacterial structure

1. Bangabandhu Sheikh Mujibur Rahman Science and
Technology University
A presentation on bacterial
structure
Presented by
Md. Shimul Bhuia
St. ID: 16PHR 003

3. The structure of bacteria
The external structure
• Flagella and motility
• Pilli
• Capsule
• Sheaths
• Prosthecae and stalks
• And cell wall
The internal structure
• The cytoplasmic
membrane
• Protoplasts and
spheroplasts
• Membranous intrusions'
and intracellular
membrane systems
• The cytoplasm
• Cytoplasmic inclusions and
vacuoles
• Nuclear material

4. Flagella
1. Flagella are
hairlike , helical
appendages
2. Composed with
flagellin protein
3. .01 to .02 m in
diameter
Part of flagella
 basal body
 hook
 and filament
use
For swimming
motility

5. Protoplast
• A protoplast is that
portion of a bacterial cell
consisting of the
cytoplasmic membrane
and the cell material
bounded by it
• 70- 90 % water
• Colorless, like jelly
• Colloidal and granulated
• Composed with protein,
carbohydrate and lipid
• And H2, N2, C, Cu, Na.

6. Function of protoplast
• Placing different molecular component
• Preparing food
• Respiration, growth, reproduction etc
• Receiving water by process of osmosis

7. Cytoplasm of bacteria
• It is cytoplasmic
matrix
• It is also called
hyaloplasm
• Semiliquid
• Colloidal and volutin
granules
• Composed of
polyphosphate
• 65-96 % water

8. Function of cytoplasm
• The first part of respiration (glycolysis)
happens here.
• Placing of micro molecular components.
• Preparing enzyme and act as container of
them.

9. Nuclear material
• There is no
membrane enclosed
nucleus
• Bacterial
chromosome consists
of a single or circular
DNA
• Circular DNA is called
plasmid

10. Pili
Pili are hollow, nonhelical, flamentantous
appendages that are thinner, shorter and
more numerous than flagella
• Composed with pilin protein

11. Capsule
• It is a thick layer of slime
material secreted by the onto
their surfaces.
• Composed of polysaccharide
• Also called glycocalyx
• Not essential for cell viability
• Found in both of Gram(+) and
Gram (-) bacteria
• Outside cell wall
• When well defined capsule
• When less defined slime
layer

12. Function of capsule
• Attachment to the surface
• Reserve of nutrients
• Protect the cell
• As antigens
• Outside envelope

13. Sheaths of bacteria
• Some species of bacteria
form chains or trichomes
that are enclosed by a
hollow tube called a
sheath
• Coated with oxide of iron
and manganese.
• Sheathed bacteria found
in soil and water
• Protect from over
temperature and pH

14. Plasma membrane
• 7.5 nm thick
• Composed with
bilayer of
phospholipids and
protein

15. Function of cytoplasmic membrane
• Surrounding the cell components
• Protecting the cell
• Controls and coordinates diffusion and
transport of essential materials
• Preparing different micro molecules

16. Cell wall
• Composed of
peptidoglycan(some
time called murein)
• 20 to 80nm thick

17. The function of cell wall
• It protects the cell
• Isolates between two cell
• Maintains the cell
• Gives rigid structure
• Essential for bacterial growth and
division

18. •Any
question?

19. Thank you