STRUCTURE AND FUNCTION OF
PROKARYOTES-PART 1
DR NAZIA KHAN
ASSISTANT PROFESSOR
OBJECTIVES:
1. CLASSIFY AND DEFINE EUKARYOTES AND PROKARYOTES
2. CLASSIFY BACTERIA AND BRIEFLY DISCUSS VARIOUS METHODS OF
CLASSIFICATION
3. DESCRIBE DIFFERENT STRUCTURES OF PROKARYOTE CELL AND THE
FUNCTIONS OF EACH STRUCTURE
WHAT ARE PROKARYOTES AND EUKARYOTES
• BELONG TO KINGDOM PROTISTA WHICH IS DIVIDED INTO
PROKARYOTES AND EUKARYOTES
• DIFFERENCES BETWEEN PROKARYOTES AND EUKARYOTES
examples
Bacteria and alga
fungi, higher plants, animals
• PROKARYOTES DON’T HAVE A MEMBRANE-BOUND NUCLEUS
• THREE FUNDAMENTAL CHARACTERISTICS ARE OFTEN
CONSIDERED TO DISTINGUISH PROKARYOTES FROM
EUKARYOTES:
i.
SMALL SIZE
ii. ABSENCE OF A COMPLEX, ORGANELLE CONTAINING
CYTOPLASM
iii. ABSENCE OF A NUCLEAR MEMBRANE
PROKARYOTES
• PROKARYOTIC CELLS ARE ABOUT 10 TIMES SMALLER THAN EUCARYOTIC CELLS
• STRUCTURALLY, PROKARYOTES ARE VERY SIMPLE CELLS WHEN COMPARED WITH EUCARYOTIC CELLS, AND YET
THEY ARE ABLE TO PERFORM THE NECESSARY PROCESSES OF LIFE.
• REPRODUCTION OF PROKARYOTIC CELLS IS BY BINARY FISSION—THE SIMPLE DIVISION OF ONE CELL INTO
TWO CELLS, AFTER DNA REPLICATION AND THE FORMATION OF A SEPARATING MEMBRANE AND CELL WALL.
• ALL BACTERIA ARE PROKARYOTES, AS ARE THE ARCHAEA.
• THE CYTOPLASM OF PROCARYOTIC CELLS IS NOT FILLED WITH INTERNAL MEMBRANES. THE CYTOPLASM IS
SURROUNDED BY A CELL MEMBRANE, A CELL WALL (USUALLY), AND SOMETIMES A CAPSULE OR SLIME LAYER
• DEPENDING ON THE PARTICULAR SPECIES OF BACTERIUM, FLAGELLA, PILI (DESCRIPTION FOLLOWS), OR BOTH
MAY BE OBSERVED OUTSIDE THE CELL ENVELOPE, AND A SPORE MAY SOME- TIMES BE SEEN WITHIN THE CELL
1.
THE OUTER LAYER OR CELL ENVELOPE
• CELL MEMBRANE
• BACTERIAL CELL WALL
2.
CELLULAR APPENDAGES:
• GLYCOCALYX (SLIME LAYERS AND CAPSULES)
• FLAGELLA
• PILI (FIMBRIAE)
3.
OTHER STRUCTURES:
CYTOPLASM
• CYTOPLASMIC PARTICLES (RIBOSOMES)
• CHROMOSOME
• SPORES (ENDOSPORE
CELL MEMBRANE, PLASMA, CYTOPLASMIC, OR CELLULAR MEMBRANE
• ENCLOSING THE CYTOPLASM OF A PROKARYOTIC CELL IS THE CELL MEMBRANE
• CHEMICALLY, THE CELL MEMBRANE CONSISTS OF PROTEINS AND PHOSPHOLIPIDS.
• IT IS FLEXIBLE AND SO THIN THAT IT CANNOT BE SEEN WITH A COMPOUND LIGHT MICROSCOPE.
FUNCTION:
1.
SELECTIVELY PERMEABLE
2.
MANY ENZYMES ARE ATTACHED TO THE CELL MEMBRANE, AND VARIOUS METABOLIC REACTIONS TAKE PLACE THERE.
3.
HOUSING MANY SENSORY AND CHEMOTAXIS PROTEINS
4.
GENERATION OF CHEMICAL ENERGY
5.
CELL MOTILITY
6.
MEDIATION OF CHROMOSOMAL SEGREGATION DURING REPLICATION
• INWARD FOLDINGS OF THE CELL MEMBRANES— CALLED MESOSOMES—ARE WHERE CELLULAR RESPIRATION TAKES PLACE IN
BACTERIA. THIS PROCESS IS SIMILAR TO THAT WHICH OCCURS IN THE MITOCHONDRIA OF EUCARYOTIC CELLS, ON THE
OTHER HAND, SOME SCIENTISTS THINK THAT MESOSOMES ARE NOTHING MORE THAN ARTIFACTS CREATED DURING THE
PROCESSING OF BACTERIAL CELLS FOR ELECTRON MICROSCOPY.
CHROMOSOME
• THE PROCARYOTIC CHROMOSOME USUALLY CONSISTS OF A SINGLE, LONG, SUPERCOILED, CIRCULAR DNA
MOLECULE,
FUNCTION:
1.
SERVES AS THE CONTROL CENTER OF THE BACTERIAL CELL.
2.
IT IS CAPABLE OF DUPLICATING ITSELF, GUIDING CELL DIVISION, AND DIRECTING CELLULAR ACTIVITIES.
• THE DNA-OCCUPIED SPACE WITHIN A BACTERIAL CELL IS SOMETIMES REFERRED TO AS THE BACTERIAL
NUCLEOID.
• BACTERIAL CHROMOSOMES CONTAIN BETWEEN 450 AND 8,000 GENES, DEPENDING ON THE SPECIES. EACH
GENE CODES FOR ONE OR MORE GENE PRODUCTS (ENZYMES, OTHER PROTEINS.
• IN COMPARISON, THE CHROMOSOMES WITHIN A HUMAN CELL CONTAIN BETWEEN 20,000 AND 30,000
GENES. SMALL, CIRCULAR MOLECULES OF DOUBLE-STRANDED DNA THAT ARE NOT PART OF THE
CHROMOSOME (REFERRED TO AS EXTRACHROMOSOMAL DNA OR PLASMIDS) MAY ALSO BE PRESENT IN THE
CYTOPLASM OF PROCARYOTIC CELLS .
CYTOPLASM
• THE SEMILIQUID CYTOPLASM OF PROCARYOTIC CELLS CONSISTS OF WATER,
ENZYMES, DISSOLVED OXYGEN (IN SOME BACTERIA), WASTE PRODUCTS,
ESSENTIAL NUTRIENTS, PROTEINS, CARBOHYDRATES, AND LIPIDS—A COMPLEX
MIXTURE OF ALL THE MATERIALS REQUIRED BY THE CELL FOR ITS METABOLIC
FUNCTIONS
CYTOPLASMIC PARTICLES
• WITHIN THE BACTERIAL CYTOPLASM, MANY TINY PARTICLES HAVE BEEN OBSERVED-RIBOSOMES
• OFTEN OCCURRING IN CLUSTERS CALLED POLYRIBOSOMES OR POLYSOMES .
• PROCARYOTIC RIBOSOMES ARE SMALLER THAN EUCARYOTIC RIBOSOMES, BUT THEIR FUNCTION IS THE
SAME—THEY ARE THE SITES OF PROTEIN SYNTHESIS.
• A 70S PROCARYOTIC RIBOSOME IS COMPOSED OF A 30S SUBUNIT AND A 50S SUBUNIT.
• CYTOPLASMIC GRANULES OCCUR IN CERTAIN SPECIES OF BACTERIA. THESE MAY BE STAINED BY USING
A SUITABLE STAIN, AND THEN IDENTIFIED MICROSCOPICALLY. THE GRANULES MAY CONSIST OF STARCH,
LIPIDS, SULFUR, IRON, OR OTHER STORED SUBSTANCES.
BACTERIAL CELL WALL
• THE RIGID EXTERIOR CELL WALL -DEFINES THE SHAPE OF BACTERIAL CELLS - CHEMICALLY COMPLEX.
• STRUCTURE OF BACTERIAL CELL WALLS IS QUITE DIFFERENT FROM THE RELATIVELY SIMPLE STRUCTURE OF
EUCARYOTIC CELL WALLS, ALTHOUGH THEY SERVE THE SAME FUNCTIONS—PROVIDING RIGIDITY,
STRENGTH, AND PROTECTION.
• CONSTITUENT OF MOST BACTERIAL CELL WALLS IS A COMPLEX MACROMOLECULAR POLYMER KNOWN
AS PEPTIDOGLYCAN (MUREIN), CONSISTING OF MANY POLYSACCHARIDE CHAINS LINKED TOGETHER BY
SMALL PEPTIDE (PROTEIN) CHAINS. PEPTIDOGLYCAN IS ONLY FOUND IN BACTERIA.
• THE THICKNESS OF THE CELL WALL AND ITS EXACT COMPOSITION VARY WITH THE SPECIES OF BACTERIA.
• THE CELL WALLS OF CERTAIN BACTERIA, CALLED GRAM-POSITIVE BACTERIA , HAVE A THICK LAYER OF
PEPTIDOGLYCAN COMBINED WITH TEICHOIC ACID AND LIPOTEICHOIC ACID MOLECULES.
• THE CELL WALLS OF GRAM-NEGATIVE BACTERIA HAVE A MUCH THINNER LAYER OF PEPTIDOGLYCAN, BUT
THIS LAYER IS COVERED WITH A COMPLEX LAYER OF LIPID MACROMOLECULES, USUALLY REFERRED TO AS
THE OUTER MEMBRANE.
BACTERIAL CELL WALL
CONT……….
• ALTHOUGH MOST BACTERIA HAVE CELL WALLS, BACTERIA IN THE GENUS
MYCOPLASMA DO NOT.
• SOME BACTERIA LOSE THEIR ABILITY TO PRODUCE CELL WALLS,
TRANSFORMING INTO TINY VARIANTS OF THE SAME SPECIES, REFERRED TO AS
L-FORM OR CELL WALL DEFICIENT (CWD) BACTERIA.
• OVER 50 DIFFERENT SPECIES OF BACTERIA ARE CAPABLE OF TRANSFORMING
INTO CWD BACTERIA, SOME OF WHICH ARE RESPONSIBLE FOR CHRONIC
DISEASES SUCH AS CHRONIC FATIGUE SYNDROME, LYME DISEASE,
RHEUMATOID ARTHRITIS, AND SARCOIDOSIS. CLINICIANS ARE OFTEN
UNAWARE THAT CWD BACTERIA ARE PRESENT IN THEIR PATIENTS BECAUSE THEY
WILL NOT GROW UNDER STANDARD LABORATORY CONDITIONS
GLYCOCALYX (SLIME LAYERS AND CAPSULES
• GLYCOCALYX LOCATED OUTSIDE THEIR CELL WALL.
• GLYCOCSLIMY, GELATINOUS MATERIAL PRODUCED BY THE CELL MEMBRANE AND SECRETED OUTSIDE OF
THE CELL WALL.
• TWO TYPES OF GLYCOCALYX. ONE TYPE, CALLED A SLIME LAYER, IS NOT HIGHLY ORGANIZED AND IS
NOT FIRMLY ATTACHED TO THE CELL WALL. EXAMPLE: PSEUDOMONAS PRODUCE A SLIME LAYER
• THE OTHER TYPE OF GLYCOCALYX, CALLED A CAPSULE, IS HIGHLY ORGANIZED AND FIRMLY ATTACHED
TO THE CELL WALL.
•
• CAPSULES USUALLY CONSIST OF POLYSACCHARIDES, FOR EXAMPLE, HAEMOPHILUS INFLUENZAE,
KLEBSIELLA PNEUMONIAE, NEISSERIA MENINGITIDIS, AND STREPTOCOCCUS PNEUMONIAE.
• CAPSULES CAN BE DETECTED USING A CAPSULE STAINING PROCEDURE, WHICH IS A TYPE OF
NEGATIVE STAIN. THE BACTERIAL CELL AND BACKGROUND BECOME STAINED, BUT THE CAPSULE
REMAINS UNSTAINED .THUS, THE CAPSULE APPEARS AS AN UNSTAINED HALO AROUND THE
BACTERIAL CELL. ANTIGEN–ANTIBODY TESTS MAY BE USED TO IDENTIFY SPECIFIC STRAINS OF
BACTERIA POSSESSING UNIQUE CAPSULAR MOLECULES (ANTIGENS).
• ENCAPSULATED BACTERIA USUALLY PRODUCE COLONIES ON NUTRIENT AGAR THAT ARE SMOOTH,
MUCOID, AND GLISTENING; THEY ARE REFERRED TO AS S-COLONIES. NONENCAPSULATED
BACTERIA TEND TO GROW AS DRY, ROUGH COLONIES, CALLED R-COLONIES.
• FUNCTIONS OF CAPSULE
1. VIRULENCE FACTOR
2. PROTECTION OF THE CELL WALL
3. IDENTIFICATION AND TYPING OF BACTERIA
MOTILITY ORGANELLES(FLAGELLA)
 FLAGELLA (SING. FLAGELLUM) ARE THREADLIKE, PROTEIN APPENDAGES
• FUNCTION: ENABLE BACTERIA TO MOVE.
• FLAGELLATED BACTERIA ARE SAID TO BE MOTILE, NONFLAGELLATED BACTERIA ARE
USUALLY NONMOTILE.
• BACTERIAL FLAGELLA ARE ABOUT 10 TO 20 NM THICK; TOO THIN TO BE SEEN WITH THE
COMPOUND LIGHT MICROSCOPE.
1.
LOPHOTRICHOUS BACTERIA: TUFT OF FLAGELLA AT ONE END ,
2.
AMPHITRICHOUS BACTERIA.: ONE OR MORE FLAGELLA AT EACH END
3.
MONOTRICHOUS BACTERIA: A SINGLE POLAR FLAGELLUM
4.
PERITRICHOUS: SURROUNDING THE CELL
• A PROTEIN SUBUNIT CALLED FLAGELLIN IS PRESENT
• THE FLAGELLUM IS ATTACHED TO THE BACTERIAL CELL BODY BY A COMPLEX STRUCTURE
CONSISTING OF A HOOK AND A BASAL BODY.
• THE HOOK IS A SHORT CURVED STRUCTURE THAT APPEARS TO ACT AS THE UNIVERSAL
JOINT BETWEEN THE MOTOR IN THE BASAL STRUCTURE AND THE FLAGELLUM.
• THE BASAL BODY BEARS A SET OF RINGS, ONE PAIR IN GRAM-POSITIVE BACTERIA AND
TWO PAIRS IN GRAM-NEGATIVE BACTERIA.
FLAGELLA CONTN………….
PILI (FIMBRIAE)
• Pili (sing., pilus) or fimbriae (sing., fimbria) are hairlike structures, most often observed on Gram-negative
bacteria.
• Composed of polymerized protein molecules called
pilin.
• Pili are much thinner than flagella, have a rigid
structure, and are not associated with motility.
• Functions: There are two types of pili: one type
merely enables bacteria to adhere or attach to
surfaces; the other type (called a sex pilus) enables
transfer of genetic material from one bacterial cell to
another following attachment of the cells to each
other.
• IN SOME SPECIES OF BACTERIA, PILIATED STRAINS (THOSE
POSSESSING PILI) ARE ABLE TO CAUSE DISEASES LIKE URETHRITIS
AND CYSTITIS, WHEREAS NONPILIATED STRAINS (THOSE NOT
POSSESS- ING PILI) OF THE SAME ORGANISMS ARE UNABLE TO
CAUSE THESE DISEASES
• A BACTERIAL CELL POSSESSING A SEX PILUS (CALLED A DONOR
CELL)— AND THE CELL ONLY POSSESSES ONE SEX PILUS—IS
ABLE TO ATTACH TO ANOTHER BACTERIAL CELL (CALLED A
RECIPIENT CELL) BY MEANS OF THE SEX PILUS.
• GENETIC MATERIAL (USU- ALLY IN THE FORM OF A PLASMID) IS
THEN TRANSFERRED THROUGH THE HOLLOW SEX PILUS FROM
THE DONOR CELL TO THE RECIPIENT CELL—A PROCESS KNOWN
AS CONJUGATION.
SPORES (ENDOSPORES)
• A FEW GENERA OF BACTERIA (E.G., BACILLUS AND CLOSTRIDIUM) ARE CAPABLE OF FORMING THICKWALLED SPORES AS A MEANS OF SURVIVAL WHEN THEIR MOISTURE OR NUTRIENT SUPPLY IS LOW.
• BACTERIAL SPORES ARE REFERRED TO AS ENDOSPORES, AND THE PROCESS BY WHICH THEY ARE FORMED
IS CALLED SPORULATION.
• SPORES ARE RESISTANT TO HEAT, COLD, DRYING, AND MOST CHEMICALS.
• SPORES SURVIVE FOR MANY YEARS IN SOIL OR DUST, AND SOME ARE QUITE
RESISTANT TO DISINFECTANTS AND BOILING.
• GERMINATION OF A SPORE MAY BE COMPARED WITH GERMINATION OF A SEED.
• HOWEVER, IN BACTERIA, SPORE FORMATION IS RELATED TO THE SURVIVAL OF THE BACTERIAL CELL,
NOT TO REPRODUCTION.
• USUALLY, ONLY ONE SPORE IS PRODUCED IN A BACTERIAL CELL AND IT GERMINATES INTO ONLY ONE VEGETATIVE
BACTERIUM
• IN THE LABORATORY, ENDOSPORES CAN BE STAINED USING WHAT IS KNOWN AS A SPORE STAIN.
• A TERMINAL SPORE IS PRODUCED AT THE VERY END OF THE BACTERIAL CELL,
• A SUBTERMINAL SPORE IS PRODUCED ELSEWHERE IN THE CELL. WHERE A SPORE IS BEING PRODUCED WITHIN THE CELL
AND WHETHER OR NOT IT CAUSES A SWELLING OF THE CELL SERVE AS CLUES TO THE IDENTITY OF THE ORGANISM.
• USES OF SPORE:
1.
IMPORTANCE IN FOOD,INDUSTRIAL AND MEDICAL MICROBIOLOGY
2.
STERILIZATION CONTROL
3.
RESEARCH
• DEMONSTRATION OF SPORE
1.
GRAM STAINING
2.
MODIFIED ZEIL NEELSON STAINING
SPORE FORMATION
CLASSIFICATION OF BACTERIA
CLASSIFICATION CAN BE DEFINED AS THE ARRANGEMENT OF ORGANISMS INTO TAXONOMIC
GROUPS (TAXA) ON THE BASIS OF SIMILARITIES OR RELATIONSHIPS.
NOMENCLATURE IS NAMING AN ORGANISM BY INTERNATIONAL RULES ACCORDING TO ITS
CHARACTERISTICS
IDENTIFICATION REFERS TO THE PRACTICAL USE OF A CLASSIFICATION SCHEME:
(1) TO ISOLATE AND DISTINGUISH DESIRABLE ORGANISMS FROM UNDESIRABLE ONES;
(2) TO VERIFY THE AUTHENTICITY OR SPECIAL PROPERTIES OF A CULTURE; OR, IN A CLINICAL
SETTING,
(3) TO ISOLATE AND IDENTIFY THE CAUSATIVE AGENT OF A DISEASE
CRITERIA FOR CLASSIFICATION OF BACTERIA
I.
MICROSCOPICALLY -CELL SHAPE ,PRESENCE OR ABSENCE OF SPECIALIZED STRUCTURES SUCH AS
SPORES OR FLAGELLA.
II.
STAINING PROCEDURES –GRAM STAINING
III.
CHARACTERISTIC PIGMENTS-
IV. ON THE BASIS OF THEIR COMPLEMENT OF EXTRACELLULAR ENZYME(ZONES OF HEMOLYSIS IN AGAR
MEDIUM CONTAINING RED BLOOD CELLS)
V.
MEASUREMENT OF THEIR SENSITIVITY TO ANTIBIOTICS
PHYLOGENETIC CLASSIFICATIONS: TOWARD AN UNDERSTANDING OF EVOLUTIONARY RELATIONSHIPS AMONG BACTERIA
DESCRIPTION OF THE MAJOR CATEGORIES & GROUPS OF BACTERIA
• THERE ARE TWO DIFFERENT GROUPS OF PROKARYOTIC ORGANISMS:
EUBACTERIA AND ARCHAEBACTERIA.
• EUBACTERIA CONTAIN THE MORE COMMON BACTERIA, THAT IS THOSE WITH
WHICH MOST PEOPLE ARE FAMILIAR.
• ARCHAEBACTERIA DO NOT PRODUCE PEPTIDOGLYCAN, A MAJOR DIFFERENCE
BETWEEN THEM AND TYPICAL EUBACTERIA. THEY ALSO DIFFER FROM EUBACTERIA
IN THAT THEY LIVE IN EXTREME ENVIRONMENTS (EG, HIGH TEMPERATURE, HIGH
SALT, OR LOW PH) AND CARRY OUT UNUSUAL METABOLIC REACTIONS, SUCH AS
THE FORMATION OF METHANE.
• THE FOUR MAJOR CATEGORIES OF BACTERIA ARE BASED ON THE CHARACTER OF
THE CELL WALL: GRAM-NEGATIVE EUBACTERIA THAT HAVE CELL WALLS, GRAMPOSITIVE EUBACTERIA THAT HAVE CELL WALLS, EUBACTERIA LACKING CELL WALLS,
AND THE ARCHAEBACTERIA
VARIOUS METHODS OF CLASSIFICATION OF BACTERIA
1.
MICROSCOPICALLY (CELL SHAPE, PRESENCE OR ABSENCE OF SPECIALIZED STRUCTURES
SUCH AS SPORES OR FLAGELLA. STAINING PROCEDURES SUCH AS THE GRAM STAIN)
2.
CHARACTERISTIC PIGMENTS EXAMPLE: PSEUDOMONAS
3.
ON THE BASIS OF THEIR COMPLEMENT OF EXTRACELLULAR ENZYMES; THE ACTIVITY OF THESE
PROTEINS OFTEN CAN BE DETECTED AS ZONES OF CLEARING SURROUNDING COLONIES
GROWN IN THE PRESENCE OF INSOLUBLE SUBSTRATES (EG, ZONES OF HEMOLYSIS IN AGAR
MEDIUM CONTAINING RED BLOOD CELLS).
4.
ON THE BASIS OF THE PRESENCE OF A RESPIRATORY ENZYME, CYTOCHROME C. TESTS SUCH
AS THE OXIDASE TEST, WHICH USES AN ARTIFICIAL ELECTRON ACCEPTOR
5.
SIMPLE BIOCHEMICAL TESTS CAN ASCERTAIN THE PRESENCE OF CHARACTERISTIC METABOLIC
FUNCTIONS.
6.
SENSITIVITY TO ANTIBIOTICS.
THANK YOU
SELF ASSESSMENT
1.
IMPORTANCE OF GLYCOCALYX IN PROKARYOTIC CELL IS
a.
PROTECTION AGAINST DESICCATION, ANTIBODIES AND VIRUSES
b.
HELPS IN DIGESTION
b.
HELPS IN REPRODUCTION
c.
HELPS IN MOTILITY
2. THE MOST COMMONLY ENCOUNTERED BACTERIA ARE ROUGHLY SPHERICAL. THE MICROBIOLOGICAL
TERM DESCRIBING THIS SHAPE IS
a.
COCCUS
b.
BACILLUS
c.
SPIRAL
d.
COMA
3. A BACILLUS BACTERIUM WITH A SINGLE FLAGELLUM AT EACH END IS DESCRIBED AS
a.
MONOTRICHOUS
b.
LOPHPOTRICHOUS
c.
AMPHITRICHOUS
d.
PERITRICHOUS
4. SHINY, STICKY COLONY OF STREPTOCOCCUS PNEUMONIAE IS LIKELY TO Be
a.
encapsulated and pathogenic
b.
.nonencapsulated and nonpathogenic
c.
nonencapsulated and pathogenic
a.
encapsulated and nonpathogenic
5. DIFFERENCES BETWEEN EUKARYOTIC AND PROKARYOTIC CELLS INCLUDE ALL OF THE FOLLOWING EXCEPT
a.
EUKARYOTIC CELLS HAVE MITOCHONDRIA
b.
PROKARYOTIC CELLS HAVE MORE COMPLEX CELL WALLS
c.
EUKARYOTIC CELLS HAVE CILIA AND FLAGELLA WITH COMPLEX STRUCTURE
d.
PROKARYOTIC CELLS HAVE NO GENETIC MATERIAL
WRITE SHORT ESSAYS ON THE FOLLOWING
1.
SPORES
2.
FUNCTIONS OF A CAPSULE
3.
CELL WALL
4.
WRITE 2 EXAMPLES OF EACH GRAM POSITIVE AND GRAM NEGATIVE BACILLI AND COCCI
5.
WHAT ARE THE DIFFERENT METHODS TO CLASSIFY BACTERIA
DRAW DIAGRAM OF A FLAGELLA