Viruses & BacteriaViruses & Bacteria

Chapter 20Chapter 20

Biology Biology

What are Viruses

A virus is a non-cellular particle made up of genetic material and

protein that can invade living cells.

T4 BacteriophageT4 Bacteriophage

Herpes VirusHerpes Virus

Escherichia Coli Escherichia Coli BacteriumBacterium

E. coli is a bacterium. That is a crude cell, it is not a E. coli is a bacterium. That is a crude cell, it is not a virus because viruses are protein containers with DNA virus because viruses are protein containers with DNA

cores or RNA cores.cores or RNA cores.

E. Coli and the E. Coli and the BacteriophageBacteriophage

What it looks like in What it looks like in real lifereal life

The Structure Of a VirusThe Structure Of a Virus

Viruses are Viruses are composed of a core composed of a core of nucleic acidof nucleic acid

The Nucleic acid core The Nucleic acid core is surrounded by a is surrounded by a protein coat called a protein coat called a capsidcapsid

The Nucleic core is The Nucleic core is either made up of either made up of DNA or RNA but DNA or RNA but never bothnever both

Cycle of Lytic and LysogenicCycle of Lytic and Lysogenic

Vaccines Vaccines

►Viruses grown on chicken embryos are Viruses grown on chicken embryos are attenuated vaccinesattenuated vaccines

►Another type of vaccine is made by Another type of vaccine is made by heat killing the virus heat killing the virus

Retrovirus

Change DNA into RNA.

Example of a Retrovirus is HIV

A typical, "minimal" retrovirus consists of: •an outer envelope which was derived from the plasma membrane of its host •many copies of an envelope protein embedded in the lipid bilayer of its envelope •a capsid; a protein shell containing •two molecules of RNA and •molecules of the enzyme reverse transcriptase

Bacteria Cell

Prokaryotes

Cells that do not have a nucleus

Exist almost every where on earth

Grow in numbers so great you can see them with the unaided eye

Are placed in either the Eubacteria or the Archebacteria Kingdoms

Make up the smaller of the two kingdoms

EubacteriaEubacteria

Make up the larger of Make up the larger of the two prokaryote the two prokaryote kingdomskingdoms

Generally are Generally are surrounded by a cell surrounded by a cell wall composed of wall composed of complex complex carbohydratescarbohydrates

CyanobacteriaCyanobacteria Photosynthetic Photosynthetic

bacteriumbacterium Bluish-greenish Bluish-greenish

colorcolor Contain membranes Contain membranes

that carry out the that carry out the process of process of photosynthesisphotosynthesis

Do not contain the Do not contain the same type of same type of chloroplasts as chloroplasts as plants doplants do

This bluish-greenish This bluish-greenish algae can be found algae can be found nearly everywhere nearly everywhere on earth.on earth.

Can survive in Can survive in extremely hot extremely hot environments and environments and even extremely cold even extremely cold environmentenvironment

ArchaebacteriaArchaebacteria Lack important Lack important

carbohydrate found carbohydrate found in cell wallsin cell walls

Have different lipids Have different lipids in their cell in their cell membranemembrane

Different types of Different types of ribosomesribosomes

Very different gene Very different gene sequencessequences

Archaebacteria can Archaebacteria can live in extremely live in extremely harsh environmentsharsh environments

They do not require They do not require oxygen and can live oxygen and can live in extremely salty in extremely salty environments as well environments as well as extremely hot as extremely hot environments.environments.

Identifying ProkaryotesIdentifying Prokaryotes

Cell ShapeCell Shape

Cell WallCell Wall

MovementMovement

Bacterium Shapes

Cocci~ Sphere shaped bacteria

Bacillus~ Rod shaped bacteria Spirrillium ~ Spiral shaped

bacteria Flagella~ Leg-like structures

that help to propel the bacterium.

Gram + and Gram – Gram + and Gram – Bacterium Cell WallsBacterium Cell Walls

Cellular WallsCellular Walls Chemical nature of a cell wall can be Chemical nature of a cell wall can be

determined by Gram Stainingdetermined by Gram Staining By finding out what color the cell produces By finding out what color the cell produces

when it is gram stained you can figure out when it is gram stained you can figure out the type of carbohydrates in the cell wallthe type of carbohydrates in the cell wall

Movement

• Flagella ~ Tail like structure the whips around to propel the bacterium

• Cillia ~ Miniature flagella surround the cell that help to “swim”

• Non motile ~ Sticky cillia like structures that keep the bacterium from moving

FlagellaFlagella

Bacteria and their energyBacteria and their energy

AutotrophsAutotrophs ChemotrophsChemotrophs HeterotrophsHeterotrophs

AutotrophsAutotrophs

Make their own Make their own energyenergy

Using Solar energyUsing Solar energy Eg. CyanobacteriaEg. Cyanobacteria

ChemotrophsChemotrophs

Make own EnergyMake own Energy Using Chemical Using Chemical

energyenergy Eg. ArchaebacteriaEg. Archaebacteria

HeterotrophsHeterotrophs

Obtain foodObtain food By eatingBy eating Eg. E-coliEg. E-coli

Bacteria RespirationBacteria Respiration

Obligate AnaerobesObligate Anaerobes Facultative Facultative

AnaerobesAnaerobes

Obligate AerobesObligate Aerobes

Live without Live without OxygenOxygen

Can live with or Can live with or without oxygenwithout oxygen

Cannot live without Cannot live without oxygen. oxygen.

Bacteria ReproductionBacteria Reproduction

Binary FissionBinary Fission ConjugationConjugation Spore FormationSpore Formation

Cellular organism copies it’s genetic information then splits into two identical daughter cells

Conjugation

A type of Bacteria Sex

Two organism swap genetic information, that contains the information such as a resistance to penicillin

Spore Formation: Spore Formation: EndosporeEndospore A type of dormant cell A type of dormant cell Exhibit no signs of lifeExhibit no signs of life Highly resistant to Highly resistant to

environmental stresses environmental stresses such as:such as:

-High temperatures-High temperatures-Irradiation-Irradiation-Strong acids-Strong acids-Disinfectants-Disinfectants

Endospores are formed by Endospores are formed by vegetative cells in response vegetative cells in response to environmental signals to environmental signals that indicate a limiting that indicate a limiting factor for vegetative factor for vegetative growth, such as exhaustion growth, such as exhaustion of an essential nutrient. of an essential nutrient.

SymbiosisSymbiosis

Close relationship Close relationship between to species between to species in which at least in which at least one species one species benefits from the benefits from the otherother

Live together for Live together for LIFELIFE

Parasitism

Bacteria exploit the host cell, injuring them

Eg. Mychobacterium tuberculosis

Mutualism

Symbiosis in which two of the species live together in such a way that both benefit from the relationship

Eg. E-coli

Nitrogen Fixations Nitrogen Fixations

Process by which nitrogen in the Process by which nitrogen in the atmosphere is converted into a form that atmosphere is converted into a form that can be used by living things can be used by living things

THE END