Microorganisms - PowerPoint Presentation

Slide1

MicroorganismsSlide2

Viruses

Biological particle composed of genetic material and protein

Cause diseases

Virulent

–immediate

Temperate -

not immediately

Obligate Parasite - only reproduces in a living hostSlide3

Viruses

Comparison with cells  

Constructed of compounds usually associated with cells  

Have some characteristics of life but not all  

No nucleus, cytoplasm, organelles, or cell membrane  

Don't reproduce by either mitosis or meiosis.  

Not capable of carrying out cellular functions  

Contain nucleic acids  

Can crystallize where cells cannot.Slide4

Viruses

Viral Structure  

Core of nucleic acid - either RNA or DNA  

Core surrounded by protein layer called Capsid

Made of repeating protein units called Capsomeres  

Gives virus its shape.  

Function of viral nucleic acid   Codes for production of viral nucleic acid.   Control manufacture protein coat.  Shape   Icosahedron - 20 triangular faces; Most common shape Polio, chicken pox, colds   Helix - subunits of coat form spiral chain - like coiled spring Rabies, mumps   Strands surrounded by 2 protein layers - inner protein layer surrounded by lipid layer with embedded glycoproteins HIV.  Slide5

VirusesSlide6

Viruses

Classification  

Major division  

RNA Viruses  

DNA Viruses  

Lower levels based on shape and size.  

Retroviruses - contains enzyme Reverse Transcriptase Directs host cell to make DNA using viral RNA of virus as a template.  Disease causing particles - smaller and simpler than virus   Viroid - short, single strand of RNA with no capsid interferes with normal cell functions   Prion - glycoprotein particle contains polypeptide of about 250 amino acids - no nucleic acid.  Slide7

Viruses

Bacteriophage(Phage) - virus that infects bacteria  

Have been used to gather information about viral replication.  

Have round, oval, or many sided heads and hollow tails  

Head contains nucleic acid

.   Tail has fibers at tip Anchors phage to bacteriaSlide8

VirusesSlide9

Viruses

Lytic Cycle - fundamental reproductive process of viruses

Consists of 5 phases.

Attachment

Entry  

Replication  

Assembly   Release  Slide10

VirusesSlide11

Viruses

Lysogenic Cycle  

Involves temperate viruses  

Viruses enter cell similar to lytic cycle

Consists of a small segment of DNA

Prophage  

Viral DNA becomes additional set of genes Incorporates into host's DNA Replicates with host DNA  External stimulus - radiation, chemicals - cause prophage to become virulent  Slide12

VirusesSlide13

Viruses

Evolution

Believed to have evolved after cells  

May be simplification of some existing cells.Slide14

Kingdoms Eubacteria and Archaebacteria

Most common members - bacteria

Bacteria Characteristics  

Prokaryotic - no nucleus

Microscopic  

Heterotrophs or autotrophs  Evolution   Fossil monerans - 3.5 billion years old.   Evolved into many forms - live in different environments.   Classification difficult; rely on physiology  Slide15

Kingdoms Eubacteria and Archaebacteria

Classification - 2 Kingdoms

Kingdom Archaebacteria  

Kingdom Eubacteria  Slide16

Kingdom Archaebacteria

 Adapted to harsh environments  

Include methanogens, extreme halophiles, and thermoacidophiles.  

Methanogens

Anaerobic

Use carbon dioxide and hydrogen to form methane

Live in bog and lake bottoms, digestive tracts of livestock, and sewerage treatment plants.   Halophiles - live in high salt areas   Thermoacidophiles - live in very acidic and hot areas  Slide17

Kingdom

ArchaebacteriaSlide18

Kingdom Eubacteria

All members of which we commonly call Bacteria

Identification  

Classified on basis of shape  

Coccus - spherical shaped cells

Bacillus - Rod shaped cells  

Spirillum - Shaped like coiled rods or corkscrews   Cells can cluster together or form chains or filaments   Staphylo - cluster Strepto -filament   Diplo - pairs   Classified on reaction to Gram stain - stains pink or purple   Gram-Negative - pink - difficult to treat with antibiotics   Gram-Positive - purple -treated with antibiotics Slide19

Kingdom

EubacteriaSlide20

Kingdom Eubacteria

Two specialized Phyla

Phylum Cyanophyta

Blue-green bacteria (algae)

Similar to plants and plant-like protists

Photosynthetic - produce food and oxygen.

Clump to form colonies Exhibit some division of laborPhylum Prochlorophyta PhotosyntheticLive symbiotically with tunicates Chlorophyll similar to eukaryotes.Slide21

Biology of Bacteria

Structure and Movement

DNA arranged in single circular chromosome  called plasmids

Cell walls differ from eukaryotes - some rigid, others flexible  

Many produce Capsule

- protective polysaccharide layer.  Glycocalyx - polysaccharide that helps many stick to surfacesPili - Protein strands to attach themselves to objects  May form endospores under adverse conditions Permits bacteria to lie dormant for years.   Favorable conditions, endospore breaks; cell becomes active.  Movement   Many move by rotating stiff flagellum bent into S-curve.   Spirochetes use filament that wraps around cell to move  Slide22

Biology of BacteriaSlide23

Biology of Bacteria

Nutrition

May be heterotrophic or autotrophic

Most are Heterotrophic

Saprophyte feeds on dead or decaying matter.   Parasite feeds on living materials   Some Autotrophic Photoautotrophs - use sunlight as energy source.  

Chemoautotrophs - use energy of chemical reactions to synthesize food.   Nitrogen Fixation

- gaseous nitrogen converted into ammonia compoundsSlide24

Biology of Bacteria

Respiration  

Obligate Anaerobes - cannot survive in presence of oxygen.  

Facultative Anaerobes - can live with or without oxygen.  

Obligate Aerobes - cannot live without oxygen.  

 Slide25

Biology of Bacteria

Reproduction  

Some reproduce rapidly - divide every 15-20 minutes  

Binary Fission - cell reproduces by splitting in two  

Asexual  

DNA replicates first  

Plasma membrane and cell wall grows inward form 2 identical daughter cells.  Conjugation - type of sexual reproduction, genetic material exchanged.   Recombination of genetic material by 2 bacteria   Portion of DNA from one cell passes across bridge formed by pili.    Recipient DNA destroyed and new DNA is substitutedSlide26

Biology of Bacteria

Toxin Production

Pathogen

- any organism that causes disease.  

Most bacterial diseases caused by toxins produced by bacteria.   Toxin - poisonous substance that disrupts metabolism of infected organism.   Endotoxin - pieces of cell wall of Gram-negative bacteria Symptoms - fever, weakness, and damage to circulatory system Example - Typhoid Fever.   Exotoxin - products of bacterial metabolism

Secreted into area around bacteria Most potent poisons known Examples - Diphtheria and Botulism (food poisoning)  Slide27

Biology of BacteriaSlide28

Kingdom Protista

Characteristics

Eukaryotic - have true nucleus.  

Most are unicellular but some live in colonies.  

Does include some simple multicellular organisms - lack specialized tissues.  

Some autotrophic; others heterotrophic.  Live in aquatic or moist environments.  Reproduce sexually and asexually.  Slide29

Kingdom Protista

Organisms placed in this kingdom because they don't have characteristics of organisms in other kingdoms.  

Separated into 3 broad groups.  

Prototozoa

- heterotrophic protists; "first animals"   Algae - autotrophic protists.   Unusual Protists - fungus like protists  Slide30

Protozoa

General Characteristics  

Heterotrophic  

Most are unicellular, some form colonies - most are microscopic.  

Live freely or as parasites (in the intestines is common)  

Many free living protozoans makeup zooplankton

Unicellular, heterotrophic organisms that drift in water.   Parasitic forms cause disease  Slide31

ProtozoaSlide32

Protozoa

Most lack a protective outer covering -

semipermeable

cell membrane serves as boundary.  

Most have physiological mechanism for monitoring and responding to environment.  

Sense touch and chemical changes - will bypass noxious chemicals.  

Eyespots (in some) - Localized region of pigment that detects changes in quality and quantity of light.  Classified into 4 phyla - based on mode of movement.   Phylum Sarcodina - move by pseudopodia   Phylum Ciliophora - move by cilia   Phylum Zoomastigina

- move by flagella.   Phylum Sporozoa - immobile; parasites  Slide33

Sarcodina - Amoeba

Most have flexible cell membrane; Some marine forms have calcium carbonate shells.

Move by means of pseudopodia - Ameboid Movement  

Pseudopodium

- "False Foot" - cytoplasmic extension that functions in movement.   Cytoplasm has 2 regions   Ectoplasm   Endoplasm  Ameboid Movement - internal flow of cell contents.  Excess water excreted by Contractile VacuoleIngest nutrients (food) by phagocytosisUndigested food and water excreted by Exocytosis

Reproduce by Binary Fission - identical offspring.  Form Cysts

- protective outer wall - when

conditions are bad

 Slide34

Sarcodina

- AmoebaSlide35

Ciliophora - Paramecium

Move by Cilia

- short,

hairlike

projectionsParamecium has rigid protein covering called Pellicle - shaped like shoe sole. Has 2 kinds of nuclei   Macronucleus - large; control cell activities Micronucleus - small; involved in sexual reproduction  Foodgetting and Digestion   Food

enters through funnel-like Oral Groove -.

C

ilia sweeps

food

to

Mouth Pore .  

Mouth pore opens into a Gullet,

forms

food

vacuoles

Contents of vacuole digested and absorbed.  

Indigestible matter in vacuole moves to the Anal Pore

-eliminated

.  

Exhibit Avoidance Behavior -

move

away from

harmful

conditions

Reproduction  

Asexual - Binary Fission - macronucleus

splits– one part to each

daughter cell

.  

Sexual – Conjugation - involves 2 mating strains; (+) or (-)  Slide36

Ciliophora

- ParameciumSlide37

Zoomastigina (Mastigophora)

Move by 1 or more long, whiplike

Flagella

Many freeliving.  

Some are parasitic

Best known - Trypanosoma - African Sleeping Sickness Transmitted by tsetse fly - live in Africa  Slide38

Sporozoa

All parasitic.  

N

o

means of locomotion -

in

body fluids of hosts.  Reproduce by spores.  Example - Plasmodium   Causes Malaria   Complex Life Cycle - in female Anophiles sp. - mosquito   Spores enter blood stream thru mosquito saliva   Spores reproduce asexually - infect red blood cells - rupture releasing toxin and more spores - causes chills and fever.   Mosquito bites infected person some of cells ingested - become gametes - combine and divide - migrate to mosquito's salivary glands to begin cycle again.  Slide39

SporozoaSlide40

Algae

General Characteristics

E

ukaryotic

, plantlike protists

Autotrophic protists -

produce food by photosynthesis.  Most aquatic - terrestrial forms in moist situations.  Unicellular and multicellular forms (large forms discussed with plants)   Thallus - Body of an alga - unicellular, colonial, filamentous, or thalloid.  

Phytoplankton - photosynthetic plankton   Provide food for numerous aquatic organisms   Generates great amounts of oxygen.

Were classified in past as plants

G

ametes

formed in

unicellular

gametangia, plant

multicellular

gametangia.  

Classified into 4 phyla - based on color, food storage substances, and cell wall composition.  

All contain chlorophyll a; usually have other forms of chlorophyll  

Contain accessory pigments.  Slide41

Chlorophyta – “Green” Algae

U

nicellular

, colonial, filamentous, or thalloid  

Most

aquatic or moist

terrestrial environments  Photosynthetic Pigments - Chlorophylls a and b; xanthophylls, carotenes  Food stored as starch.  Cell wall composition - Polysaccharide, sometimes cellulose  Importance - Believed to be ancestors of plants  Slide42

Chlorophyta

– “Green” AlgaeSlide43

Chrysophyta – “Golden Brown” Algae

Mostly unicellular  

Photosynthetic pigments - Chlorophylls a and c; Carotenes - fucoxanthin  

Food stored as Chrysolaminarin - oily carbohydrate  

Cell wall if present of cellulose, some contain silica  

Most members are Diatoms

  Marine and freshwater specimens   Have silica containing shells - highly ornamented, double walls.   Halves fit together like a box

- half called Valve   Types  

Centric Diatoms

- circular or triangular valves - marine waters.  

Pennate Diatoms - rectangular valves - freshwater ponds and lakes  

R

esponsible

for bulk of worldwide photosynthesis.  

Diatom shells don't decompose - forms

Diatomaceous

Earth

- abrasive

-

ingredient

in detergents, paint removers, fertilizers, insulators, scouring powders.  Slide44

Chrysophyta

– “Golden Brown” AlgaeSlide45

Pyrrophyta – “Fire” Algae

Most are marine;

oceanic

phytoplankton -

called

Dinoflagellates

- all unicellular  Photosynthetic pigments - chlorophylls a and c; Carotene  Food stored as starch  Cell wall of cellulose - looks like armor.  responsible for Bioluminescence - light produced by living things.  Produce "Red Tides" - discoloration of ocean ; population explosion of dinoflagellates - produce toxins may cause respiratory paralysis in vertebrates  Slide46

Pyrrophyta

– “Fire” AlgaeSlide47

Euglenophyta – “True Eye” Algae

Have characteristics of green algae and protozoa.

Contain chlorophylls a and b, carotenes in some.

Food stored as a starch - Paramylon

Have no cell wall, surrounded

by pellicle

Not completely autotrophic, heterotrophic - in the dark.Mostly freshwater species.Contractile vacuole gets rid of excess water.Moves by whipping flagellum.  Red-orange eyespot functions as light detectorSlide48

Euglenophyta

– “True Eye” AlgaeSlide49

Fungus Like Protists

Members of group traditionally classified as fungi - actually are protists

Life cycles look fungus like  

Store food as glycogen

Morphological differences considered superficial  Slide50

Fungus Like Protists

Phylum Acrasiomycota - Slime Molds  

Live mostly on land or in freshwater.  

Feeding stage

-

Myxameb

a - uninucleate cell   Live on forest floor or on decaying plants   Move and feed like amoeba  During environmental stress myxameba come together to form a Pseudoplasmodium   Group of individual cells that act as one unit  Moves together.   Unit forms sporangia that produce spores   Spores develop into individual myxameba  Slide51

Fungus Like

ProtistsSlide52

Fungus Like Protists

Phylum Myxomycota - Plasmodial Slime Molds  

Feeding stage

-

Plasmosium

- multinucleate cytoplasm surrounded by a membrane that moves as a mass, feeds on organic matter  Stressful periods - plasmodium becomes stationary - produces sporangia on stalks  Sporangia produce spores - may be dormant for years.  Spore releases myxameba or flagellate swarm cells   Cells fuse; nucleus for zygote divides repeatedly  

Doesn't undergo cytokinesis

Multinucleate

plasmodium  Slide53

Fungus Like

ProtistsSlide54

Kingdom Fungi

Diverse group living in many different habitats.

Characteristics  

Eukaryotic  

Many

microscopic; some easy to see.  Important as decomposers - breakdown organic materials   Release inorganic materials to environment to be reused.   Most are either parasitic or saprophytic; a few predatory.   Parasite - organism that lives off of living organisms.   Saprophyte

- organism that lives off of dead organisms or waste products.  Generally grow in moist environments.   Slide55

Kingdom Fungi

Characteristics

Composed of vegetative filament called a Hypha

- may or may not be divided by cross walls.  

Coenocytic - filaments without crosswalls.   Hypha may be have perforated crosswall - Septum.   Hypha grows at tip.   Mycelium - a mat of interwoven hyphae.   Made of Chitin

- complex polysaccharide, also in exoskeleton of arthropods and insects.  

Food stored as glycogen.  

 Slide56

Kingdom Fungi

Characteristics

Reproduce both sexually and asexually.  

Asexual Reproduction  

Produce spores

on

special branches of hypha   Spores often carried by wind.   Finds suitable food source germinates; new hyphae grows  May reproduce asexually by fragmentation   Sexual Reproduction  

Gametes from 2 mating strains undergo cytoplasmic fusion.   Nuclei don't fuse immediately - divide

independently.  

Heterokaryotic

-

different

nuclei

Homokaryotic

-

similar nuclei

.Slide57

Kingdom Fungi

Classification  

Basis  

Structure of hyphae  

Coenocytic Hyphae – No crosswalls  

Septate Hyphae - With crosswalls  

Unicellular Hyphae - single cell   Type of Reproduction - particularly spore type.  Five Phyla   Phylum Oomycota   Phylum Zygomycota   Phylum Basidiomycota   Phylum Ascomycota   Phylum Deuteromycota  Slide58

Oomycota

A

quatic

and terrestrial species - water molds, white rusts, and downy mildews  

Both parasitic and saprophytic  

Coenocytic with branched hyphae  

Cell walls have cellulose not chitin  Reproduction   Male gametangium, antheridium, release sperm   Female gametangium, oogonium, forms egg   Fusion of egg and sperm develops thick-walled diploid Oospore

  Oospore germinates into coenocytic hyphae  

Asexual reproduction - flagellated zoospores produce hyphae  

Example -

Phytophthora infestans

  - Late Blight of Potatoes  

Irish Potato Famine of 1845-47  

Result - mass migration of Irish to United States.  Slide59

Zygomycota – Rhizopus

Bread Mold

terrestrial

organisms  

Coenocytic - hyphae lack septa  

Reproductive structures are separated from other hyphae by unperforated cross walls  

Rhizopus consists of 3 types of hyphae   Rhizoids - anchoring hyphae – absorb nutrients   Stolons - hyphae that grow across surface of bread   Sporangiophore - upright hyphae - sporangia at their tips  

Reproduction   Asexual - spores from a sporangium on

sporangiophore

.  

Sexual - Conjugation - two strains unite to form a Zygospore

Favorable conditions -asexual reproduction

Unfavorable conditions - sexual

reproductionSlide60

Zygomycota

–

Rhizopus

Bread MoldSlide61

Basidiomycota – Club Fungi

Mushrooms, toadstools, puffballs, rusts, and smuts - mostly terrestrial

Septate hyphae

Underground hyphae produce Basidiocarp - reproductive body

Mushroom is a basidiocarp.

Stalk - stem-like portion Cap - flattened top portion Gills - radiating rows under cap - site of basidia; Basidium - club-shaped reproductive cell; produces Basidiospores Hyphae

grows - septa form - called Primary Mycelium

Hyphae grow,fuse with another mating strain – Secondary mycelium forms.  

Hyphae heterokaryotic - one nucleus in each cell.  

Secondary mycelium forms basidiocarp.  

Asexual reproduction by fragmentation.  

Importance  

Rusts - parasites of many cereal crops  

Smuts - plant pathogens - particularly corn  

Mushrooms - some food value  Slide62

Basidiomycota

– Club FungiSlide63

Ascomycota – Sac Fungi

Includes yeasts, molds, mildews, and morels - terrestrial and aquatic species.  

Have septate or unicellular hyphae  

Reproduction  

Asexual  

Spores called Conidium – on Conidiophores   Yeast asexual reproduction is by Budding   Sexual   Two mating strains form male or female gametangia   Female gametangium – Ascogonium

  Male gametangium – Antheridium   Gametangia fuse - nuclei pair but don't fuse  

Hyphae intertwine

form an

Ascocarp

- reproductive body  of ascomycete; contains sacs -Asci

(ascus)

that produce ascospores.  

Yeast important – able to breakdown carbohydrates  

Bread/Baking Industry - use carbon dioxide from anaerobic respiration  

Brewing Industry - fermentation of juices/liquids  Slide64

Ascomycota

– Sac FungiSlide65

Deuteromycota

Imperfect Fungi

Taxonomic holding tank -

fungi

that

where no

sexual reproductive phase has been discovered.   Have characteristics similar to ascomycetes   Classified on basis of asexual reproduction.   Aspergillis and Penicillium - former deuteromycetes now classified as ascomycetes   Aspergillis - ferments soy beans makes soy sauce   Penicillium - produce antibiotic penicillin; gives flavor to Roquefort and Camembert cheeses  

Septate hyphae  

Terrestrial species  

Asexually

Reproduce by

conidia.  Slide66

Deuteromycota

Imperfect FungiSlide67

Symbiotic Relationships

MUTUALISM

- type of symbiosis in which both organisms benefit

Examples

Mycorrhizae

Symbiotic association between fungi and plant roots

Lichens Symbiotic association between a fungus (usually an ascomycete and a green algae or cyanobacteria Slide68

Mycorrhizae

Symbiosis between fungi and plant roots  

Help plants absorb water and nutrients

Fungus forms extensive network of hyphae in soil - increases surface area.  

A

ction

of fungal enzymes provide nutrients that can be readily absorbed by the plant.  Fungi absorbs of sugar produced by plant Slide69

MycorrhizaeSlide70

Lichens

Symbiosis between a fungus (usually an ascomycete and a green algae or cyanobacteria

Considered

symbiotic-may be

a controlled parasitism

Fungal hyphae penetrate

algal cells and absorb foodFungal member provides some protection against drying of algae.Lichens classified according to thallus   Crustose - grow surface of rocks and trees   Foliose - have leafy thallus   Shrubby - upright growth; also called 2-fold lichens  Slide71

LichensSlide72

Disease

Any change, other than injury, that interferes in normal functioning of a body.  

Pathogen

- Disease causing microorganism

Infection

- Invasion of a body by a pathogen.Slide73

Germ Theory of Disease

Idea that disease is caused by microorganisms.  

Earlier belief was that disease was caused by evil spirits, magic, or miasmas (vapors of marshes or decaying organic matter.)  

Based on work of Louis Pasteur (French) and Robert Koch (German)  

Koch’s Postulates  

Microorganism should always be found in host but not in a healthy organism.  

Microorganism must be isolated and grown in pure culture away from host.  When microorganisms of pure culture are injected into new host, they should cause disease.  Microorganisms should be reisolated from second host and grown in pure culture and identified as the same as the original pure culture.  Slide74

Germ Theory of DiseaseSlide75

Disease

Agents of Disease  

Viruses  

Bacteria  

Fungi  

Protozoa