Viruses & Bacteria

Viruses & Bacteria

What are Viruses A virus is a non-cellular particle made up of genetic material and protein that can invade living cells.

T4 Bacteriophage

Herpes Virus

Escherichia Coli Bacterium

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

E. Coli and the Bacteriophage

What it looks like in real life

The Structure Of a Virus 

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Viruses are composed of a core of nucleic acid The Nucleic acid core is surrounded by a protein coat called a capsid The Nucleic core is either made up of DNA or RNA but never both

Cycle of Lytic and Lysogenic

Vaccines ► Viruses

grown on chicken embryos are attenuated vaccines ► Another type of vaccine is made by heat killing the virus

Retrovirus 

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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   

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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

Eubacteria Make up the larger of the two prokaryote kingdoms Generally are surrounded by a cell wall composed of complex carbohydrates

Cyanobacteria   

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Photosynthetic bacterium Bluish-greenish color Contain membranes that carry out the process of photosynthesis Do not contain the same type of chloroplasts as plants do This bluish-greenish algae can be found nearly everywhere on earth. Can survive in extremely hot environments and even extremely cold environment

Archaebacteria  Lack important carbohydrate found in cell walls  Have different lipids in their cell membrane  Different types of ribosomes  Very different gene sequences  Archaebacteria can live in extremely harsh environments  They do not require oxygen and can live in extremely salty environments as well as extremely hot environments.

Identifying Prokaryotes Cell Shape Cell Wall Movement

Bacterium Shapes 

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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 – Bacterium Cell Walls

Cellular Walls 

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Chemical nature of a cell wall can be determined by Gram Staining By finding out what color the cell produces when it is gram stained you can figure out the 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

Flagella

Ba cte ria a nd t heir ener g y   

Autotrophs Chemotrophs Heterotrophs

Autotrophs   

Make their own energy Using Solar energy Eg. Cyanobacteria

Chemotrophs  

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Make own Energy Using Chemical energy Eg. Archaebacteria

Heterotrophs   

Obtain food By eating Eg. E-coli

Bacteria Respiration  

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Obligate Anaerobes Facultative Anaerobes

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Obligate Aerobes

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Live without Oxygen Can live with or without oxygen Cannot live without oxygen.

Bacteria Reproduction   

Binary Fission Conjugation Spore Formation

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

Conjugation 

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A type of Bacteria Sex Two organism swap genetic information, that contains the information such as a resistance to penicillin

Spore Formation: Endospore  A type of dormant cell  Exhibit no signs of life  Highly resistant to environmental stresses such as: -High temperatures -Irradiation -Strong acids -Disinfectants  Endospores are formed by vegetative cells in response to environmental signals that indicate a limiting factor for vegetative growth, such as exhaustion of an essential nutrient.

Symbiosis 

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Close relationship between to species in which at least one species benefits from the other Live together for LIFE

Parasitism 

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Bacteria exploit the host cell, injuring them Eg. Mychobacterium tuberculosis

Mutualism 

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Symbiosis in which two of the species live together in such a way that both benefit from the relationship Eg. E-coli

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

THE END