This document discusses the structure of bacteria. It begins by explaining that bacteria are simpler and smaller than other cells, lacking organelles. It then outlines the internal structure of bacteria, including the cytoplasm, nucleoid, ribosomes, and plasmids. The external structure contains features like pili, capsules, and flagella. A key part of the bacterial structure is the cell wall and cell barriers, which vary between gram-positive and gram-negative bacteria in terms of composition and thickness. The cell wall functions to maintain shape and protect the cell, while assisting in processes like cell division.

1. ALL ABOUT
MICROBIOLOGY

3. STRUCTURE
OF BACTERIA • By Saba

4. STRUCTURE OF
BACTERIA
• Simpler and smaller
• No recognisable organelles
• Small in size
• Divide rapidly

5. STRUCTURE OF
BACTERIA
• Three categories:
I. Internal structure
II. External structure
III. Cell barriers

6. CELL BARRIERS
• Cell barriers include cell membrane and
peptidoglycan cell wall.
• The structure, chemical composition and
thickness is different in both gram
negative and gram positive bacteria.

7. INTERNAL
STRUCTURE
• Cytoplasm
• Nucleoid
• Bacterial chromosome
• Ribosomes
• Plasmid
• Granules used for storage

8. EXTERNAL
STRUCTURE
• Pilli
• Capsule
• Flagellum
• Fimbriae

9. STRUCTURE OF BACTERIA

10. CELL WALL
• Outer most layer
• Mostly, Comes in direct contact with
environment
• It maintain the shape of bacteria
• Protect the cell
• Maintain osmotic regularity

11. FUNCTIONS
• Assist attachment to the other cells
• Attachment to antimicrobial drugs
• Attachment to bacteriophage
• Assist in cell division

12. PEPTIDOGLYCAN
• Also known as Murein
• Polymer of sugar
• Forms mesh like layer outside cell
membrane
• Thicker in gram positive bacteria
• Thinner in gram negative bacteria

14. • Structure in gram
Positive &
Negative
bacteria

15. GRAM POSITIVE
BACTERIA
• Thick peptidoglycan layer
• 50-90% of dry weight
• Fibers of teichoic acid in large ammount

16. GRAM
NEGATIVE
BACTERIA
• Multilayer
• complex
• Thin peptidoglycan layer
• Fibers of teichoic acid
• Outer layer consist of Lipopolysaccharide,
lipoprotein and phospholipid

18. • Lying between outer membrane and
cytoplasmic membrane called periplasmic
space
• It is the site in which beta lactamases
degrade penicillin and other drugs

19. IMPORTANT
POINTS
• Gram negative bacteria, contain
endotoxin
• Polysaccharide and protein used for lab
identification
• Porin helps in passage of hydrophilic
molecule into the cell like sugar, vitamin,
metals and antimicrobial drugs

20. CELL WALL IN
ACID FAST
BACTERIA
• Unusual cell wall
• Inability to gram stain
• They resist decolorization with acid
alcohol
• It is due high concentration of lipids
• Mycolic acid (cell wall of Mycobacterium)

21. THANK YOU