1. Collage of Basic Science and Hummanities
Submitted to : Dr. Anurag Yadav Asst. Prof. of Microbiology Submitted by : Lalpara Ajay Kumar A. 6th sem. Microbiology Reg.No : Roll No. : 15 Seminar Topic: Anatomy and Physiology of prokaryotic cell i

2. Anatomy And Physiology of Prokaryotic Cell

3. Bacterial Shapes, Arrangements, and Sizes
Vary in shape, size, and arrangement but typically described by one of three basic shapes:
Coccus – spherical
Bacillus – rod
Coccobacillus – very short and plump
Vibrio – gently curved
Spirillum – helical, comma, twisted rod,
Spirochete – spring-like 3 3

4. Bacterial Shape and Arrangement

5. Bacterial Arrangements
Arrangement of cells is dependent on pattern of division and how cells remain attached after division:
Cocci:
Singles
Diplococci – in pairs
Tetrads – groups of four
Irregular clusters
Chains
Cubical packets (sarcina)
Bacilli:
Diplobacilli
Palisades 5 5

6. Arrangement of bacilli

7. Prokaryotic Cell Structure

8. Cytoplasmic Membrane
Surrounds cytoplasm and defines boundaries of cell
Acts as barrier, but also functions as an effective and highly discriminating conduit between cell and surroundings
Made up of phospholipid bilayer

9. Movement of Molecules through Cytoplasmic Membrane
Several ways for molecules to move through membrane
Simple Diffusion
Osmosis
Facilitated Diffusion
Active Transport

10. Simple Diffusion Does not require expenditure of energy
Process by which some molecules move freely into and out of the cell
Small molecules such as carbon dioxide and oxygen

11. Transport Proteins
Transport proteins (or transporters) responsible for:
Facilitated Diffusion
Active Transport

13. Cell Wall Composed of peptidoglycan
Comprised of alternating NAG and NAM molecules
Attached to each NAM is four amino acid peptide: tetrapeptide

14. Categories of Bacteria
Two Major Categories:
Difference due to difference in chemical structures of their cell walls
Gram positive: stains purple
Gram negative: stains red

15. Gram-Positive Cell Wall
Thick, homogeneous sheath of peptidoglycan
20-80 nm thick
Includes teichoic acid and lipoteichoic acid: function in cell wall maintenance and enlargement during cell division; move cations across the cell envelope; stimulate a specific immune response
Some cells have a periplasmic space, between the cell membrane and cell wall

16. Gram-Negative Cell Wall
Composed of an outer membrane and a thin peptidoglycan layer
Outer membrane is similar to cell membrane bilayer structure
Outermost layer contains lipopolysaccharides and lipoproteins (LPS)
Lipid portion (endotoxin) may become toxic when released during infections
May function as receptors and blocking immune response
Contain porin proteins in upper layer – regulate molecules entering and leaving cell
Bottom layer is a thin sheet of peptidoglycan
Periplasmic space above and below peptidoglycan 16 16

17. Outer Membrane Unlike any other membrane in nature
A lipid bilayer with the outside layer made of lipopolysaccharides instead of phospholipids
Also called LPS
Contains Porins

18. Periplasm - Region between cytoplasmic membrane and the outer membrane
- Gel-like fluid
Filled with secreted proteins and enzymes

19. External Structures
Flagella
Axial Filaments
Fimbrae and Pili

20. Filamentous Protein Appendages
Anchored in membrane and protrude from surface
Flagella: long structure responsible for motility
Fimbrae and Pili: shorter, responsible for attachment

21. Fimbriae
Fine, proteinaceous, hairlike bristles emerging from the cell surface
Function in adhesion to other cells and surfaces

22. Pili Rigid tubular structure made of pilin protein
Found only in gram-negative cells
Function to join bacterial cells for partial DNA transfer called conjugation

23. Four types of bacteria with flagella
Montrichious- one flagella
Amphitrichous- flagella at both ends
Lophitrichous- many flagella at the end of the cell
Peritrichous- flagella all over entire cell

24. Axial Filament Present in Spirochetes
Attach at end of cell, spiral around, underneath an outer sheath
Move like a corkscrew

26. Internal Structures of Prokaryotic Cells

27. Cytoplasm Substance of cell inside the cytoplasmic membrane
About 80% water
Thick, aqueous, semitransparent, elastic

28. Chromosome Found within a central location known as nucleoid
Single, circular, double stranded
Consists of all DNA required by cell

29. Plasmids Small circular, double-stranded DNA
Free or integrated into the chromosome
Duplicated and passed on to offspring
Not essential to bacterial growth and metabolism
May encode antibiotic resistance, tolerance to toxic metals, enzymes, and toxins
Used in genetic engineering - readily manipulated and transferred from cell to cell 29 29

30. Ribosomes Made of 60% ribosomal RNA and 40% protein
Consist of two subunits: large and small
Prokaryotic differ from eukaryotic ribosomes in size and number of proteins
Site of protein synthesis 30 30

32. Endospores Occurs in members of genera Bacillus and Clostridium
Dormant cell produced by a process called Sporulation
Germination- when they exit the dormant state and then become a vegetative cell
Several species of endospore formers can cause disease