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MicroMicroViruses,
Bacteria, Fungi
OrganismsOrganisms
Microbesare Roles
Non-cellular Cellular
Virus
Nucleic Acid Host Cells
DNA or RNA
Shapes
Spiral-likeRod-like spherical
BacteriophageTobaccomosaicvirus
Influenzavirus
Biochemical System
Prokaryotes
Types
Bacteria
Shape
Cocci Bacilli Spirrilli
O2 requirement
Aerobic Anaerobic
Unicellular
Cytoplasm
NoMembrane
-boundorganelles
No truenuclei
Circular DNA
Cell membrane
Cell wall
Prokaryoticfission
Spores Conjugation
Reproduce
Eukaryotes
Fungi
Unicellular
Multicellular
YeastCell
membrane
Cell wall
Cytoplasm
Membranebound
organelles
True nuclei
DNAhelix
Mycellium
hyphae
ChitinousCellwall
Reproduce
asexual Sexual
budding spores
are
are
gametes
Extra-cellular
digestion
Parasitic
Saprophytic
are either
consists of
Made up of
Which is either
Infects
By taking over its
have
Such as
e.g.e.g.e.g.
Classified as
Can be classified by
According to
Such as
Vibrio-gamma
with flagella
yes no
have
surrounded by
contains
with
thushas
butcontains
can
by
Consist of
are either
e.g.
have
sometimes surrounded by
contains
with
e.g.
with
have
consisting of
protected by
can
either
viavia
carryout
Protein coatSurrounded by
Penicilliume.g.
Viral materialTo replicate
Resulting in lysis of
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VirusesViruses
Viruses: IntroductionViruses: IntroductionPathogens in bacteria, plants & animals
Small, about 0.2 um
Only visible under electron microscope(Max. magnification: x 250 000)
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Viruses: ShapeViruses: ShapeSpherical:Influenza virus
Rod-shaped:Tobacco mosaicvirus
Tadpole-shaped:Bacteriophages
Viruses: StructureViruses: StructureInternal core: Nucleic acid (DNA/RNA)
Protein coat
Envelope
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Viruses: Not cellsViruses: Not cellsNo protoplasm
Only reproduce inside hostcells
Cannot generateenergy/synthesize proteins
Inert outside of host cells
Behave like living organisminside host cell
Viral DiseasesViral Diseases
InfluenzaChicken poxDengue haemorrhagicfeverHerpesAIDSSARS
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Viral DiseasesViral DiseasesViruses can only be destroyed byantibodies produced by our white bloodcellsAntibiotics, used to kill bacteria, are NOTeffective against viruses
BacteriaBacteria
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Bacteria: IntroductionBacteria: IntroductionLiving cells
Barely visible under light microscope
Larger than viruses, about 0.005 mm
Bacteria: StructureBacteria: StructureBacterium: Single-celled organism
Cell wall of peptidoglycan, proteins, fats,carbohydrates
No chloroplasts
Glycogen granules
Lipid droplets
Slime capsule
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Bacteria: StructureBacteria: StructureNo nuclear envelope
Single circular loop of DNA
Bacteria chromosomecontains genes
Plasmids in cytoplasmTransfer genes btwn. species
Non-motile/MotileFlagellum
Bacteria: ShapesBacteria: ShapesCocci (S: coccus):Spherical shaped
Bacilli (S: bacillus):Rod shaped
Spirilla (S: spirillum):Spiral shaped
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Bacteria in the environmentBacteria in the environmentFound in:
Air
Water (fresh &salt)
Hot springs
Soil
Bodies ofanimals (esp.in theintestines)
Bacteria: NutritionBacteria: NutritionSaprophytic
Feeding on decaying organic matter
ParasiticFeeding on living hosts
Causing diseases in plants & animals
AutotrophicMaking own food with sunlight &inorganic compounds
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Bacteria: ReproductionBacteria: ReproductionBinary fission:
The bacterial cellcopies the DNA itcontains andthen splits in halfto form two newcells
Bacteria: RespirationBacteria: Respiration
Aerobic: Require oxygen forrespiration
Anaerobic: Surviving in theabsence of oxygen
Some can live in the presence orabsence of oxygen
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Bacteria: Spore formationBacteria: Spore formation
Formation of sporesAdverse conditions
Thick wall
Resistant to cold andheat
Suitable medium:Grow and multiply
FungiFungi
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Fungi: IntroductionFungi: IntroductionSome live as saprophytes
Decaying organic matter
Some as parasites of plants &animals
Can be:Unicellular
Multicellular
Unicellular FungiUnicellular FungiEg. Yeast
Mayreproduce bybudding
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Multicellular Multicellular FungiFungiBread mould / rhizopus
Mushrooms
Penicillium (producesantibiotic penicillin)
Bread mouldBread mouldConsists of a mesh of fine, thread-likehyphae (singular: hypha)
Collectively known as mycelium
Each hypha is non-septateWithout cross-walls
Many nuclei in the cytoplasm
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Bread mouldBread mouldCell wall is composed of chitin(complex carbohydrate)
Carbohydrate store: Glycogen
Mould: ReproductionMould: ReproductionReproduction: By spores
MinuteResistant to adverseconditions (eg. drought)Dispersed by windGrow into mycelia whenthey settle on suitablemedium
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Fungi: NutritionFungi: NutritionDigestion is extracellular
Hyphae secrete enzymes(amylase, maltase, protease)Digest organic food substancesoutside their bodies
Digested food (glucose &amino acids are absorbedby diffusion into the hyphaeSuch activities of fungi enablethem to play a role asdecomposers
MitosisBudding (yeast)Mitosis (moulds)
Binary fissionDependent on hostcell machinery
Method ofReplication
- Cell membrane- Cell wall (made ofchitin)
- Cell membrane
- Cell wall(made of peptidoglycan)- Cell membrane
- Protein coat(capsid)
- Envelope(may not be present)
Outer Surface
PresentPresentAbsentAbsentOrganelles*
Eukaryotic(Nuclearenvelopepresent,linearchromosomesof DNA)
Eukaryotic (Nuclearenvelopepresent, linearchromosomesmade of DNA)
Prokaryotic (No nuclearenvelope, singlecircularchromosome madeof DNA)
NoneNucleus
Both DNA & RNABoth DNA & RNABoth DNA & RNAEither DNA or RNANucleic Acid15-253-10 (yeasts)1-50.02-0.2Diameter (um)
Yes (Unicellular)Yes (Unicellular -yeasts
Multicellular –moulds)
Yes (Unicellular)NoCells
ProtozoaFungiBacteriaVirusesFeatures
Comparisons between Micro-organisms
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In nature: AsdecomposersBiotechnology:- Production ofcheese- Yeast:Production of bread& alcohol- Penicillium:Production ofpenicillin (anantibiotic)- Fusarium:Production ofmycoprotein (single-cell protein)
In nature: AsdecomposersGenetic engineering:As vectors, as well as toproduce human insulinBiotechnology:Production of yoghurtand cheese, single-cellproteinSewage treatment
Genetic engineering:As vectors
Usefulness
Malaria (causedby Plasmodium),sleeping sickness
Athlete’s foot,thrush, potato blight(in plants)
Pneumonia, cholera,syphilis, leprosy,tuberculosis, tetanus
Influenza, chickenpox, denguehaemorrhagic fever,herpes, AIDS ,SARS
Diseasescaused
ProtozoaFungiBacteriaVirusesFeatures
Comparisons between Micro-organisms
Microbes Microbes Topic 4.2Topic 4.2in Decomposition
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DecompositionDecomposition
Decomposersplay anessential rolein the cyclingof nutrients innature
DecomposersDecomposersFungi and certain bacteria
Carry out saprophytic nutrition
Feed on dead, decaying organisms & faeces
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DecomposersDecomposers
Secrete enzymes onto their food source
Break down complex organiccompounds into simple, soluble orgaseous inorganic compounds
Absorb only a small amount of energyand nutrients for own use
Most of the energy is lost as heat
DecomposersDecomposersRemaining nutrients are releasedinto surrounding air, soil, and water
Gases: Carbon dioxide, hydrogensulphide, water vapour
Salts: Nitrates, sulphates, phosphatesand potassium ions
Reused by green plantsPhotosynthesis
Synthetic processes
Eg. Protoplasm building
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ImportanceImportanceRecycling of nutrients betweenliving organisms & environment.
Prevent the accumulation of remains& wastes of living organisms on earth.
Sewage Treatment ISewage Treatment ISewage is decomposed bysaprophytic microorganisms
Passed through filters to removelarge objects
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Sewage Treatment IISewage Treatment IIDrained into large setting tanks
Bacteria present secrete enzymes
Digest the solid organic matter intosoluble, harmless substances
Carbon dioxide is produced
Sewage TreatmentSewage TreatmentThe liquid that results from digestion
Filtered
Pathogens removed (treated withchlorine)
Discharged into the rivers & seas
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Sewage TreatmentSewage TreatmentThe digested solid, called sludge
Removed from the tank
Dried
Used as fertilizers
Sewage TreatmentSewage Treatment
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T4.3 BiotechnologyT4.3 Biotechnology
Explain the role of yeast in the productionof bread and alcoholOutline the role of bacteria in yoghurt andcheese productionDescribe the use of fermenters for large-scale production of antibiotics and singlecell proteinDescribe the role of the fungusPenicillium in the production of penicillin.
Role of YeastRole of YeastBread making: Yeast is added to the dough. Lack ofoxygen inside the dough causes the yeast to respireanaerobically, fermenting the maltose to alcoholand carbon dioxide.Alcohol: Yeast is used in brewing, to convert thesugar present food substances (barley, or grapes) intoalcohol and carbon dioxide during anaerobicrespiration (fermentation).Grape juice is used in the making of wine.
The Japanese sake is produced from fermentation ofrice.
In spirit-based drinks, like whisky, the alcohol isseparated from the fermented liquors or mashes (e.g.malt barely) by distillation.
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Role of bacteriaRole of bacteria
Yoghurt: Streptococcus is added to the milk toremove oxygen, thereby creating an anaerobiccondition. In the absence of oxygen, the Lactobacillusrespires anaerobically to break down lactose (milksugar) to lactic acid. This acid causes the milkprotein, casein, to curdle (coagulate, semi-solidstate).Cheese: Bacteria and Fungi
Lactobacillus is used to ferment milk sugar to lacticacid. The acid curdles milk protein.The curdled protein, together with the fats in the milk, isremoved and acted upon by a mixture bacteria and fungi,which will partly digest them to fatty acids and amino acids.
Role of the fungus Role of the fungus PenicilliumPenicillium
Penicillin is a byproduct excreted by the fungusPenicillium. It is an antibiotic, used mainly inthe treatment of bacterial diseases.
Initially, when the nutrient level is high, there is rapidgrowth of the fungus; but the penicillin production is low.When nutrient level becomes low, growth rate slows downand penicillin production increases.
Involves the use of giant fermenters
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Industrial BiotechnologyIndustrial Biotechnology
Choice of microorganisms used inBiotechnologyFermenters: For large-scale, rapid production ofmicroorganisms and their products
Cooling systemAeration system
2 types of operating systemsBatch operating system used inpenicillin productionContinuous operating system usedin SCP production
Single-cell Protein (SCP)Single-cell Protein (SCP)
Proteins made from microorganisms such asbacteria and yeast, are called single-cell proteins.Advantage of SCP – high protein and fibre, lowfat, rich in vitamins.Eg, Mycoprotein is a food made for humanconsumption from the fungus called Fusarium.
In mycoprotein production, it is the fungal cells that areharvested, and the protein contents within the cells areextracted. In penicillin production, it is the excretoryproduct of the fungus Penicillium that is extracted fromthe nutrient medium.
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Microbeshave roles in
Ecosystem
Types
Biotechnology
Industrial processFood production
Fermentation Fermenters
Yoghurt Cheese Bread Alcohol
Bacteria:Lactobacillus
andStreptococcus
BacteriaAnd
Fungus
Fungus:Yeast
Antibiotics Single celled proteins
Mycoprotein
Bacteria
Pruteen
Animal feed Human foodStreptomycin Penicillin
BacteriaStreptomyces
FungusPenicillium
DecompositionParasitism Symbiosis
LichensMycorrhizae
Ringwormon man
Whitespot in fish
Have processes such as
e.g.E.g.
e.g.
Involves use
to produce
by by by
for large-scaleproduction of
e.g.
from from
Used in
e.g.e.g.
fromfungus
from
Decomposersby
Bacteria Fungi
Such as
Nutrient Cycling
Complex organic substances
Simple inorganic substances
PhotosynthesisOther synthetic processes
Which are involved in
In which
Are broken down to
Used in
Waste accumulation Maintain life processes
To Prevents
Sewage Treatment
Speeds up
Prevents
Involves
Makes use of