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Viruses & Bacteria. Chapter 17 Biology 11 Presentation put together by Mandie Lynn Walls. 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.
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Viruses & Bacteria Chapter 17 Biology 11 Presentation put together by Mandie Lynn Walls
What are Viruses A virus is a non-cellular particle made up of genetic material and protein that can invade living cells.
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 • 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
Vaccines • Viruses grown on chicken embryos are attenuated vaccines • Another type of vaccine is made by 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
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
Eubacteria • Make up the larger of the two prokaryote kingdoms • Generally are surrounded by a cell wall composed of complex carbohydrates
Cyanobacteria • 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 • Cocci~ Sphere shaped bacteria • Bacillus~ Rod shaped bacteria • Spirrillium ~ Spiral shaped bacteria • Flagella~ Leg-like structures that help to propel the bacterium.
Cellular Walls • 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
Bacteria and their energy • Autotrophs • Chemotrophs • Heterotrophs
Autotrophs • Make their own energy • Using Solar energy • Eg. Cyanobacteria
Chemotrophs • Make own Energy • Using Chemical energy • Eg. Archaebacteria
Heterotrophs • Obtain food • By eating • Eg. E-coli
Obligate Anaerobes Facultative Anaerobes Obligate Aerobes Live without Oxygen Can live with or without oxygen Cannot live without oxygen. Bacteria Respiration
Bacteria Reproduction • Binary Fission • Conjugation • Spore 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: 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 • Close relationship between to species in which at least one species benefits from the other • Live together for LIFE
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 • Process by which nitrogen in the atmosphere is converted into a form that can be used by living things
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