Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download welcome to the wonderful world of bacteria & viruses
Document related concepts
Transcript
WELCOME TO THE WONDERFUL WORLD OF BACTERIA & VIRUSES ANTHRAX ANTHRAX- not just a band CELLULITIS CHICKEN POX ECZEMA ECZEMA ERYSEPILAS ERYSEPILAS HERPES- ocular IMPETIGO IMPETIGO LEPROSY LYME DISEASE MEASLES Small Pox Chicken Pox Polio MONONUCLEOSIS MONONUCLEOSIS MUMPS NECROTIZING FACSIITIS NECROTIZING FACSIITIS NECROTIZING FASCIITIS Necrotizing Fasciitis SHINGLES I HOPE YOU ENJOYED OUR BRIEF TOUR THROUGH THE WONDERFUL WORLD OF BACTERIA & VIRUSES! BACTERIA • Prokaryotes: single-celled organisms that lack a nucleus Bacterial Kingdoms (formerly Monerans) • Divided into TWO KingdomsArchaebacteria- “ancient bacteria” Eubacteria- “good/true bacteria” ARCHAEBACTERIA • Characteristics – Most live in harsh environments – Cell wall does NOT contain peptidoglycan – DNA sequence similar to eukaryotes (possible ancestor?) Types of Archaebacteria • • • • • EXTREMOPHILES Methanogens- produce methane Halophiles- live in salty conditions Thermophiles- live in high temperatures Etc. What might I find in… • Gut of a cow? – Methanogens • Hot spring? – Thermophiles • Dead Sea? – Halophiles EUBACTERIA • Live almost anywhere • Cell wall contains peptidoglycans • Wide array of characteristics Types of Eubacteria • Gram-positive: cell wall mainly peptidoglycan – Appear purple when stained • Gram-negative: cell wall of less peptidoglycan with second layer of lipids and carbohydrates – Appear pink when stained Archaebacteria vs. Eubacteria Characteristic ArchaePeptidoglycan in cell wall? No Live in… Harsh environments DNA sequence like eukaryotes? Yes EuYes Almost everywhere No How are bacteria identified? • Shape: – Bacilli- rod – Cocci- sphere – Spirilla- spiral – *Strepto- chains – *Staphylo- clusters What would these look like? • Streptobacillus – Chains of rod-shaped bacteria • Streptococcus – Chains of sphere-shaped bacteria • Staphylococcus – Clusters of sphere shaped bacteria How are bacteria identified? • Cell Walls – Is peptidoglycans present? • Yes- Eubacteria: gram + = a lot • No- Archaebacteria gram - = a little How are bacteria identified? • Movement – Some have flagella, cilia – Some glide, spiral, etc. – Others don’t move on own How are bacteria identified? • Energy obtaining methods – Autotrophs- make own food • Phototrophs- use light • Chemotrophs- use inorganic materials – Heterotrophs- take in food – Photoheterotrophs- need light and a nutrient source What organisms can… • Use light to make food? – Phototrophs • Make own food but also need light? – Photoheterotroph • Use inorganic materials to make food? – Chemotrophs • Make their own food? – Autotrophs How bacteria are identified? • Energy releasing processes: – Cellular respiration: requires Oxygen (Obligate aerobes) – Fermentation: no Oxygen used (Obligate anaerobes) – Some can survive with or without oxygen (Facultative anaerobes) How are bacteria identified? • Reproduction & Growth: – Binary Fission- double in size, replicates DNA, splits into two (asexual) Reproduction cont’d – Conjugation- bridge forms between two cells and genes are transferred Conjugation – Endospores- thick wall around DNA can remain dormant until conditions are favorable VIRUSES • Virus- Latin for “poison” • Smaller than bacteria • NOT living! Structure of a Virus • Infectious agent made up of a core of nucleic acid (DNA or RNA) and a protein coat (capsid) Why not living? • Viruses can’t replicate on their own- they must use a host’s cells • Not made of cells • Cannot maintain homeostasis • Cannot metabolize Replication (Reproduction) • 2 Types of Replication: – Lytic Cycle – Lysogenic Cycle Lytic Cycle • Virus enters the cell, makes copies of itself, and causes the cell to burst Steps of Lytic Cycle – Virus attacks cell and injects DNA – DNA forms a circle Steps of Lytic Cycle cont’d – Viral DNA commands host cell to make new viruses Lytic Cycle Steps cont’d – Cell bursts and releases viruses to invade more cells – *Symptoms of disease show Lysogenic Cycle • Virus embeds its DNA into the host’s DNA • Both DNAs are replicated • Prophage- viral DNA that is embedded into host’s DNA • *Symptoms of disease do not show at this time • At some point, virus may be triggered to enter lytic cycle Types of Viruses • Bacteriophage- virus that infects bacteria Types of Viruses- cont’d • Retroviruses- contain RNA as genetic code (HIV & AIDS, some cancer) RNA • Oncogenic viruses- cause cancer in animals (disrupt controls over cell growth) Not quite a virus, but… • Prions- “protein infectious particles” – Act like a virus, but… – Do not contain any DNA or RNA, only protein • Usually only affects animals • Viroids– Act like a virus, but… – Has RNA, but no capsid • Usually only affects plants Protection from viruses- HOW? • PREVENTION! – Good hygiene – Vaccines- weakened or “killed” viruses or viral particle • Inject into body to build up immunity
