Viruses & Bacteria
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Transcript of Viruses & Bacteria
Viruses & Bacteria
Chapter 17Biology 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
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
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
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
EubacteriaMake up the larger of the two prokaryote kingdomsGenerally 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 ProkaryotesCell ShapeCell WallMovement
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 – Bacterium Cell Walls
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
Flagella
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
Bacteria Respiration Obligate
Anaerobes Facultative
Anaerobes
Obligate Aerobes
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
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
THE END
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