microorganisms

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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