4. Cell wall
Cell wall is multilayer structure located external to
cytoplasm membrane
Internally it is composed of peptidoglycan and external
structure vary according to the bacterial type
Provide structural support t and maintain shape of cell
Cell wall of acid fast bacteria have mycolic acid
Sugar backbone with peptide side chains that are cross
linked
Give rigid support, protect against osmotic pressure
5. flagella
Characteristics:
Filamentous protein appendages attached to cell surface
Have swimming movements incase of motile bacteria
Have tactic behaviour(ability to move in response to
enviroment stimuli)
Composition
Basal body
Hook
Long filament of polymerized protein called flagellin
Division on basis of locomotion
Polar(one area of cell)
Peritrichous(entire bacterial cell)
6. capsule
Characteristics:
Bacteria produce or excrete high molecular weight of
polysaccride sugar coating called capsule
Located outside the cell
Functions:
Provide protection to bacteria from host
Protect from phagocytosis
Help in bacterial adhesion
7. Endospore
characteristics
special structure formed by some bacteria(Bacillus,C
lostridium)
Resistant to heat,chemicals,radiations and chemicals)
Sporulation
Spore to vegetative cycle
8. Pilli(fimbrae)
Characteristics:
Hair like filament short than flagella
Composed of subunit of pillin
Proteins are arranged in helical strand
Mainly found in gram negative organisms
Function:
Attached to specific receptor
Sex pilli(attachment)
11. Structures internal to cell wall
Cytoplasm
Thick,aqous,semitransparent and elastic material
Contain ribosomes and various types of nutriental storage
granules
About 80% water containing carbohydrates,proteins and
lipids
12. nucleus
Consist of polyamine magnesium ions bond to negatively
charge circular super coiled double stranded DNA,small
amount of RNA and other proteins
Cells genetic information which carries all the information's
requires for cell structures and function
Purified nucleotides reveal that they composed of 60%
DNA 30% RNA 10% proteins by weight
13. plasmid
Small circular non chromosomal double stranded DNA capable
of self replication
Most frequently extra chromosomal but may become integrated
into bacterial DNA
Function:
Contain genes that confirm protective properties such as
antibiotics resistance are virulence factors are their own
transmissibility of other bacteria
Plasmid play role in the lives of the organisms that have them
Types:
Episomes
Conjugate
colplasmid
14. Ribosomes
Complex structure made of protein and RNA
Shape of protein is determined by its amino acid sequence
Risbosome present in cytoplasm loosly attach in plasma
membrane
70S ribosome in prokaryotes,weight 2.7million
15. Inclusion bodies
Several kind of deposits in cytoplasm
Useful when enviroment is deficient
Avoid osmotic pressure
Metachromatic bodies use for storage
16. Mesosomes
Structure invagination of plasma membrane
Two types
Septal mesosomes
Lateral mesosomes
Functions:
DNA replication
Cell division
secretion
17. Cytoplasmic membrane
Composed of phospholipids bilayer
Does not contain sterol
Cytochrome enzyme involved in electron transport and
oxidative phosporilation,lipids , enzymes and P binding
protein involved in cell wall biosynthesis
Function
Selectively permeability and active transport
Site of action of certain antibiotics such as polymixin
18. Transposomes
Small piece of DNA that move bacteria rapidly from one
side to another between the DNA of the bacteria plasmid
and bacteriophage
Also called jumping genes
Function:
Code for antibiotic resistance and enzymes metabolic
enzymes and toxins
May alter expression of neighboring genes are cause
mutation to genes into which they are inserted
19. Teichoic acid
Are water soluble polymers containing a ribitole and
glycerol residue linked by phosphodiaster bonds
Found in cell wall and is bonded to peptidoglycan
Lipotechicacid is found in cell membrane and bounded to
membrane glycolipid in mesosomes specially
Functions
Important bacterial surface ,antigenic determinants
It helps anchor the wall to membrane