1. Dr: Walaa Ahmed Alshareef

2. Bacterial Cytoplasm
It is a gelatinous mass of proteins, carbohydrates, lipids, nucleic acids, salts and inorganic ions, all are dissolved in water. It contains about 70 to 80% water.
It is thick, semi-transparent and elastic.
It contains different stages of cellular materials, nutrients, metabolic products, enzymes and proteins as well as some granules. Such as:
Ribosomes site of protein synthesis
Inclusion bodies (globules of starch, protein or lipid)
Metachromatic granules.
Magnetosome : crystal of an iron containing compounds helps certain bacteria to move and direct towards their preferred habitat.
Inclusion bodies مشتملات
metachromatic granule  a granular cell inclusion present in many bacterial cells, having an avidity for basic dyes and causing irregular staining of the cell.

3. Bacterial Granules
They are present in the cytoplasm

4. Bacterial Endospores
Some gram-positive bacteria are able to produce highly resistant structure called endospores or simply spores.
The genera Bacillus and Clostridium are good examples for spore­-formers.
Spores are more capable of resisting unfavorable conditions.
Spores does not multiply (not reproductive process).
It is considered as a dormant form of bacteria.
Spores may have the same diameter of the cell or may be larger.
The position of the spores may be central, terminal or sub-terminal.
Dormant خامل

5. Spores of Bacillus
Spores of Clostridium

6. Bacterial Endospores It has a survival function
1) Resist drying, heating, desiccation, and pH.
2) The reasons for resistance to unfavorable conditions are:
(i) It contains a cementing substance (Calcium Dipicolinate)
(ii) It contains disulfide bond which resists denaturation of protein
(iii) It contains low moisture contents
When exposed to higher temperatures, such as that of boiling water, the internal bonds of the bacteria’s folded enzyme relax to form long chains of protein molecules. These chains move about freely in the low water content of an endospore’s core region. Since the functional enzyme shape has relaxed, the cell machinery stops and the dormant state associated with the endospore is the result. When cell temperature becomes more hospitable, the protein chains refold back into the the normal enzyme structure. At this point, the cell returns to normal functioning.

7. So, The Intracellular Structures are:
Bacterial Cell Wall
Bacterial Cell Membrane
Bacterial Cytoplasm
Bacterial Granules
Bacterial Endospores
What about Extracellular Structures??

8. Flagella
Flagella are composed of long, rigid strands of a protein called Flagellin.
This structure permits the flagellum to rotate, where the strands are flexible, and long (whip-like) structure.
They are present only in rod-shaped bacteria ranges in length from 10 µm to 20 µm.
They are antigenic.
Flagella can vary in number and placement.

9. Flagella IF bacterium has 1) Single Flagellum called (monotrichous)
2) Group of two or more Flagella at one pole called (lophotrichous)
3) Group of two or more Flagella at both ends called (amphitrichous)
4) Covered with Flagella called
(peritrichous)

10. Flagella

11. Pili (Fimbriae)
Pili has no function for motility. It has a major role in cell attachment.
Pili enhanced organism's ability to cause disease.
They are commonly found in gram negative bacteria.
Common pili = fimbriae for adherance
Conjugative or sex pili = for transfere DNA from cell to another

12. Capsules (K antigen)
It composed of mucilaginous materials secreted by the cells, attached to the cell wall possibly via covalent attachments to either the murein (peptidoglycan) layer of gram-positive bacteria and the outer membrane (Lipopolysaccharide layer) of gram-negative bacteria.
It is a very sticky, gelatinous structure.
It composed mainly from polysaccharides and sometimes polypeptides.
It forms in various species of bacilli and cocci, but not in spiral bacteria.
It has antigenic properties.
Capsule= Protein which is part of a capsule, the protective structure surrounding some bacteria or fungi. The bacterial capsule is a layer of material, usually polysaccharide, attached to the cell wall possibly via covalent attachments to either phospholipid or lipid-A molecules. It has several functions: promote bacterial adhesion to surfaces or interaction with other organisms; act as a permeability barrier, as a defense mechanism against phagocytosis and/or as a nutrient reserve. Among pathogens, capsule formation often correlates with pathogenicity. The fungal capsule is an extracellular layer which lies outside the cell wall and it is usually composed of polysaccharides. It protects the cell from different environmental dangers such as phagocytosis, dessication, etc.
Capsule (also known as K antigen) is a major virulence factor of bacteria, e.g. all of the principal pathogens which cause pneumonia and meningitis, including Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Klebsiella pneumoniae,  Escherichia coli, and group B streptococci have polysaccharide capsules on their surface. Nonencapsulated mutants of these organisms are avirulent.

13. The function of capsule:
protect the cell against phagocytosis and rehydration due to its high water content.
Capsulated bacteria can be mutated to non-capsulated species (avirulent)
Receptors for Bacteriophages
Initiation of infection

14. The function of capsule:
Development of Vaccines: Capsular polysaccharides are used as the antigens in certain vaccines.
Identification of bacteria The capsulated type forms smooth colonies (S) on plate cultures, while the non-capsulated types formed rough colonies (R).

15. Glycocalyx or Slime layer
It composed of polymer of sugar like capsule. called dextran.
Glycocalyx helps the cell to attach and adhere to solid surface.
Some bacteria adhere to teeth by glycocalyx, forming dental plaque.
Entrapment of lactic acid produced by bacteria causing dental caries.

16. Bacterial Motility
It is usually associated with the presence of flagella.
Most spiral bacteria and about half of the bacilli are motile. But cocci are generally non-motile.
Motility can be observed best in young culture in a semisolid medium or by the hanging drop technique.
Some bacteria exhibit gliding motility by secreted slime on solid medium.

17. Gliding movement of bacteria

18. Thank you
Please study well :_)
Dr: Walaa Al-Shareef