Virus, Bacteria,Virus, Bacteria,Protists, and FungiProtists, and Fungi

Chapters 19-21Chapters 19-21

What a virus is… and What a virus is… and isnisn’’t.t. A virus is not a cell.A virus is not a cell.

– No nucleus, cell membrane, ribosomes, No nucleus, cell membrane, ribosomes, mitochondria, chloroplasts, etc.mitochondria, chloroplasts, etc.

A virus is very small.A virus is very small.– 3000 poloviruses could be contained in 3000 poloviruses could be contained in the period at the end of this the period at the end of this sentence.sentence.

A virus is not complex.A virus is not complex.– Genes: Humans (100,000), Bacteria Genes: Humans (100,000), Bacteria (1000), a Virus… just 5!(1000), a Virus… just 5!

Viral StructureViral Structure Nucleic AcidNucleic Acid

– DNA or RNA, but not both.DNA or RNA, but not both. Protein Coat (capsid)Protein Coat (capsid)

– Protects the nucleic acid from its Protects the nucleic acid from its environment.environment.

EnvelopeEnvelope– Only found in viruses that infect Only found in viruses that infect animals.animals.

– Spike-like projections that recognize Spike-like projections that recognize animal cells and bind to the cell animal cells and bind to the cell surface.surface.

T4 BacteriophageTobacco Mosaic

Virus Influenza Virus

Head

Tail sheath

DNA

Tail fiber

RNACapsid

Surfaceproteins Membrane

envelope

RNA

Capsidproteins

Section 19-2

Viral ReplicationViral Replication Viruses donViruses don’’t reproduce, they replicate.t reproduce, they replicate. Viruses cannot replicate on their own.Viruses cannot replicate on their own. Host cells.Host cells. Lytic Cycle.Lytic Cycle.

– When the virus enters the cell it immediately When the virus enters the cell it immediately begins to replicate, rapidly killing the begins to replicate, rapidly killing the cell.cell.

Lysogenic Cycle.Lysogenic Cycle.– Viral DNA is inserted into the host cellViral DNA is inserted into the host cell ’’s s DNA. This DNA, called a DNA. This DNA, called a PROPHAGEPROPHAGE, may be , may be reproduced several times and eventually reproduced several times and eventually reactivates.reactivates.

Lytic and Lysogenic Infections

Are viruses alive?Are viruses alive? Properties of Life:Properties of Life:

– Highly organized. Highly organized. Yes or no?Yes or no?– Use energy. Use energy. Yes or no?Yes or no?– Grow and develop. Grow and develop. Yes or no?Yes or no?– Reproduce. Reproduce. Yes or no?Yes or no?– Respond and adapt. Respond and adapt. Yes or no?Yes or no?

Most scientists would say… Most scientists would say… NO.NO.

Section 19-2

Figure 19-11 Viruses and Cells

What are What are vaccinations?vaccinations? The process of injecting a The process of injecting a person with a harmless person with a harmless (weakened or dead) form of a (weakened or dead) form of a virus to stimulate the virus to stimulate the immune system to produce immune system to produce cells and proteins that will cells and proteins that will destroy that type of virus.destroy that type of virus.

Bacterial StructureBacterial Structure Figure 14.10Figure 14.10

– FlagellaFlagella– Cell MembraneCell Membrane– RibosomeRibosome– PiliPili– ChromosomeChromosome– Cell WallCell Wall

Peptidoglycan

Cell wall

Cell membrane

Ribosome

Flagellum DNA Pili

Section 19-1

The Structure of a Eubacterium

Survival/ReproductionSurvival/Reproduction Binary Fission:Binary Fission: the process by which the process by which bacteria replicate chromosomes and the bacteria replicate chromosomes and the cell divides.cell divides.

Power of doubling (1 penny doubled 20 Power of doubling (1 penny doubled 20 times)times)

1048576 cents or $10,485.761048576 cents or $10,485.76 Average bacteria doubles every 15-20 Average bacteria doubles every 15-20 minutesminutes

EndosporesEndospores– Thick-walled reproductive structures Thick-walled reproductive structures that can resist heat, drought, and that can resist heat, drought, and radiation, sometimes living centuries radiation, sometimes living centuries before breaking open.before breaking open.

Classifying BacteriaClassifying Bacteria Archaebacteria Archaebacteria (( ““ancientancient””))

– Methanogens: produce methane.Methanogens: produce methane.– Thermophiles: heated conditionsThermophiles: heated conditions– Halophiles: salty conditionsHalophiles: salty conditions

EubacteriaEubacteria– ““True BacteriaTrue Bacteria”” – live in much less – live in much less harsh environments than archebacteria. harsh environments than archebacteria. Many types and ways to classify.Many types and ways to classify.

Classifying Bacteria, Classifying Bacteria, cont.cont.

ShapesShapes– Spheres (Spheres (coccicocci), rods (), rods (bacillibacilli), ), spirals (spirals (spirillaspirilla), chains ), chains ((streptococcistreptococci), clusters ), clusters ((staphylococcistaphylococci).).

Cell Wall CompositionCell Wall Composition– Gram-positive, Gram-negative.Gram-positive, Gram-negative.

Nutrition Nutrition (autotroph, heterotroph)(autotroph, heterotroph) Respiration Respiration (aerobes, anaerobes)(aerobes, anaerobes)

The Roles of BacteriaThe Roles of Bacteria Decomposers.Decomposers.

– Breakdown dead material.Breakdown dead material.– Convert (fix) nitrogen into Convert (fix) nitrogen into usable forms for plants.usable forms for plants.

Symbiosis.Symbiosis.– ““You scratch my back – IYou scratch my back – I’’ll scratch ll scratch yours.yours.””

Bacteria can be harmful.Bacteria can be harmful.– Slides of deadly bacteria.Slides of deadly bacteria.

Tooth decay

Lyme disease

Tetanus

Tuberculosis

Salmonella food poisoning

Pneumonia

Cholera

Streptococcus mutans

Borrelia burgdorferi

Clostridium tetani

Mycobacterium tuberculosis

Salmonella enteritidis

Streptococcus pneumoniae

Vibrio cholerae

Regular dental hygiene

Protection from tick bites

Current tetanus vaccination

Vaccination

Proper food-handling practices

Maintaining good health

Clean water supplies

Disease Pathogen Prevention

Section 19-3Common Diseases Caused by Bacteria

Oncogenic viruses

Retrovirus

Adenoviruses

Herpesviruses

Poxviruses

DNA

RNA

DNA

DNA

DNA

Cancer

Cancer, AIDS

Respiratory infections

Chickenpox

Smallpox

Type of Virus Nucleic Acid Disease

Section 19-3

Common Diseases Caused by Viruses

ProtistsProtists Common characteristic: Common characteristic: EUKARYOTESEUKARYOTES

Very diverse (20 new kingdoms?)Very diverse (20 new kingdoms?) Three general categories:Three general categories:

– Animal-Like Protists (p. 355-357)Animal-Like Protists (p. 355-357)– Plantlike Protists (p. 358-361)Plantlike Protists (p. 358-361)– Funguslike Protists (p. 362-364)Funguslike Protists (p. 362-364)

Section 20-1Concept Map

are classified by

which includewhichwhich which

Protists

Animallike FunguslikePlantlike

ParasitesTake in food from the environment

Produce food by photosynthesis

Obtain food by external digestion

Decomposers

Animallike Protists: ProtozoansAnimallike Protists: Protozoans

A.A. ZooflagellatesZooflagellates

B.B. SarcodinesSarcodines

C.C. CiliatesCiliates

1.1. Internal AnatomyInternal Anatomy

2.2. ConjugationConjugation

D.D. SporozoansSporozoans

Section 20-2

Food vacuole

Nucleus

Contractile vacuole

Pseudopods

Section 20-2

Figure 20-4 An Amoeba

Anal pore

GulletOral groove

TrichocystsLysosomes

Food vacuoles

Contractile vacuole

Micronucleus

MacronucleusCilia

Section 20-2

Figure 20-5 A Ciliate

Plantlike Protists: Unicellular Plantlike Protists: Unicellular AlgaeAlgae

A.A. Chlorophyll and Accessory Chlorophyll and Accessory PigmentsPigments

B.B. EuglenophytesEuglenophytes

C.C. ChrysophytesChrysophytes

D.D. DiatomsDiatoms

E.E. DinoflagellatesDinoflagellates

Section 20-3

Section Outline

Gullet

Chloroplast

NucleusEyespotFlagella

Section 20-3 Euglena

Carbohydrate storage bodies

Pellicle

Contractile vacuole

Plantlike Protists: Red, Brown, and Plantlike Protists: Red, Brown, and Green AlgaeGreen Algae

A.A. Red AlgaeRed Algae

B.B. Brown AlgaeBrown Algae

C.C. Green AlgaeGreen Algae

1.1. Unicellular Green AlgaeUnicellular Green Algae

2.2. Colonial Green AlgaeColonial Green Algae

3.3. Multicellular Green AlgaeMulticellular Green Algae

Funguslike ProtistsFunguslike Protists

A.A. Slime MoldsSlime Molds

1.1. Cellular Slime Cellular Slime MoldsMolds

2.2. Acellular Slime Acellular Slime MoldsMolds

B.B. Water MoldsWater Molds

Section 20-5

Section Outline

MEIOSIS

FERTILIZATION

ZygoteGerminating spore

SporesMature

sporangiumYoung sporangium Mature

plasmodium

Feeding plasmodium

Haploid (N) Diploid (2N)

Section 20-5

Figure 20-23 The Life Cycle of an Slime Mold

FungiFungi 3 Common characteristics:3 Common characteristics:

– Cell wall are Cell wall are chitinchitin.. Same Same covering as insects.covering as insects.

– Made of individual filaments, Made of individual filaments, called called hyphaehyphae.. Tubes full of Tubes full of cytoplasm and nuclei.cytoplasm and nuclei.

– Masses of hyphae combine to Masses of hyphae combine to form the form the myceliummycelium. . This is the This is the body of the fungus.body of the fungus.

Hyphae Without Cross Walls

Nuclei

Cell wall

Nuclei

Cytoplasm

Cross wall

Cell wall

Cytoplasm

Hyphae With Cross Walls

Section 21-1

Hyphae Structure

FERTILIZATION

MEIOSIS

HYPHAE FUSE

Fruiting body (N + N)

Button

Secondary mycelium (N + N)

Primary mycelium (N)

+ Mating type (N)

- Mating type (N)

Basidiospores (N)

Zygote (2N)

Basidia (N + N)

Gills lined with basidia

Gills

Stalk

Base

Cap

Haploid

Diploid

Section 21-2

The Life Cycle of a Basidiomycete

How does a fungus How does a fungus eat?eat? HeterotrophsHeterotrophs DiffusionDiffusion:: most fungi absorb most fungi absorb small organic nutrients from small organic nutrients from their environment.their environment.

SaprophyticSaprophytic:: they absorb they absorb nutrients from dead or decaying nutrients from dead or decaying organic matter.organic matter.