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Bacteria=Prokaryotes Prokaryotes No organelles except ribosomes NO NUCLEUS! Eukaryotes Lots of organelles INCLUDING NUCLEUS! Bacterial Characteristics Oldest organisms: 3.5 billion yrs. old. Live in almost every environment. Eubacteria Kingdom Eubacteria Common environments Believed to be the ancestors of mitochondria and chloroplasts--organelles in eukaryotic cells Archaebacteria Kingdom Archaebacteria Found in extreme environments Ancient bacteria-gave rise to eukaryotic cells Characteristics-Size Size • • • Red blood cell is 250X’s larger than a bacterium 1 gram of soil can contain 2.5 BILLION bacteria Relative bacteria size Characteristics-Shapes Shapes: Cocci-round Bacilli-rod-shaped Spirilla-spiral Bacterial structure Interior structures Has DNA and cytoplasm—no nucleus or other membrane bound organelles EXCEPT ribosomes for protein synthesis! Bacterial Structure Bacterial structure Exterior structures Flagella--whip-like tail for locomotion Cell membrane to control what goes in and out Cell wall for protection 2 Types of Cell Walls 2 types of cell walls found in bacteria Identified as Gram + or Gram There’s a chemical difference b/t them. Gram staining Special staining process “Gram positive is purple; Gram negative is not.” 2 Types of Cell Walls Gram + Thick cell wall Holds purple stain, so cells look purple Gram Two thin layers make up cell wall Doesn’t hold purple stain so appears pink 2 Types of Cell Walls Treatment of illness due to these bacteria is different! Gram - : generally NOT affected by antibiotics i.e. E. coli Gram +: affected by antibiotics i.e. S. pneumoniae Bacterial Reproduction Binary fission Bacteria’s process of reproduction where 1 becomes 2. Results in clones 1000’s of bacteria that result from one undergoing binary fission is called a colony How are bacteria so diverse? They have several ways of exchanging genetic information. Conjugation--exchanging DNA through a straw-like tube. Transformation—another method of transferring genes between bacteria. Useful Bacteria Decomposers- Recycle nutrients such as CO2 , water, nitrogen, and phosphorus Useful Bacteria •Nitrogen fixation- soil bacteria take nitrogen gas from the air (N2) and change it into a useable form that plants can absorb (NH3ammonia.) •Plants use the nitrogen to produce their proteins and DNA. •Some bacteria are photosynthetic and also provide oxygen N2 Bacteria NH3 YUMMY! Useful Bacteria Food-- yogurt, olives, pickles, chocolate Drugs -- insulin production Clean up oil spills Animal digestion and vitamins, including our own Microbe Discovery Movie Harmful Bacteria Pathogen- Disease causing organisms. Pathologists -scientists who study pathogens. Not many bacteria are pathogenic— ONLY 1%! Disease Transmission: a.) Water b.) Air c.) Food d.) Animals/Insects e.) Human Contact Bacterial Diseases Tuberculosis Syphilis Bubonic Plague Typhus Tetanus Lyme Disease Controlling Bacterial Growth What do bacteria require to live and reproduce? - Food, water, and the right climate. -Give bacteria these things, and they grow; remove them and they don’t. Nutrition and Energy How do bacteria “eat”? 1.) Autotrophic- “self-feeders” MAKE food *Photosynthetic so they release oxygen!!! HAVE NO ORGANELLES SO NO CHLOROPLASTS!!! *Chemosynthetic 2.) Heterotrophic- “other-feeders” GET food *Consumers *Decomposers *Parasites Growing Bacteria on Petri Dishes Plastic Petri dishes have a Jell-O like substance called AGAR with nutrients and water for bacteria to grow on. Growth Curve When bacteria are grown on agar in a Petri dish, their food and water supply (AGAR) is limited They live through four phases of growth without addition of more agar. Lag Log Stationary Death GROWTH CURVE Controlling Growth Antibiotics Antibiotic resistance Sanitizing--Antiseptics and Disinfectants Freezing Cooking Pasteurizing Dehydrating Vaccination Antibiotics Alexander Fleming Mold on his Petri dish had a zone of inhibition around it where bacteria didn’t grow. Mold released the antibiotic penicillin Antibiotic=against life; any BACTERIA substance produced by a microbe that slows the growth of other microbes. MOLD Antibiotics 2 ways antibiotics control bacteria: Bacteriocidal- kill them by blocking protein synthesis Bacteriostatic- prevent them from undergoing binary fission (prevents them from making new cell walls.) BACTERIA Each paper disk has antibiotics on it. Which antibiotic is more powerful? Antibiotics Antibiotics are made by : fungus (mold) other bacteria, the most common Streptomyces. present day antibiotics are synthetic modifications of naturally occurring ones. Work on Gram + bacteria Antibiotic Resistance Movie Antibiotic resistant bacteria are not affected by certain antibiotics! Can be resistant due to: Special cell walls (i.e. Gram – bacteria) OR Special antibiotic resistant genes Don’t finish antibiotics: Weaker bacteria destroyed. **Resistant bacteria still live and pass on resistant genes through binary fission, conjugation and transformation Conjugation Sanitizing Antiseptics---Chemicals used to inhibit growth of bacteria on living tissues Sanitizing Disinfectants—Chemicals used to inhibit growth of bacteria on NON-living things. Freezing How would this control the growth of bacteria? Would freezing kill all the bacteria? Cooking Cooking can control bacterial growth and kill most bacteria if heated to certain temps—165F or hotter. Use a meat thermometer Wash hands after handling raw meat Pasteurizing Using heat to kill bacteria in liquids. Dehydrating How would this control the growth of bacteria? Vaccination Prevents you from getting the disease. DOES NOT CURE YOU. Fast and strong immune system memory cells produced which provides immunity just like if you got the disease (i.e. chicken pox.) Vaccination Can use weakened (attenuated) bacteria or viruses MOSTLY use parts of bacteria or viruses— acellular Vaccine video Structure of a Virus Virus: a microscopic particle that invades and takes over cells Relative virus size 100% of viruses are pathogenic!!!! Structure of a Virus (cont.) Made of: nucleic acid (DNA or RNA) surrounded by a protein coating (capsid). Viral Replication Parasites (dependent on host for replication) Steps of viral replication: 1.) Recognition of marker protein on specific cell types. 2.) Attachment 3.) Injection (of nucleic acid) 4.) Assembly 5.) Lysis (cell bursting) Characteristics of Living Things Homeostasis: stable internal conditions Metabolism: use energy Reproduction Made of cells Genetic material VIRUSES ARE NOT LIVING THINGS! *****No metabolism, homeostasis, reproduction, or cells Replication Cycles of Viruses: 2 Types Viruses have either a lysogenic or lytic replication cycle: Lytic: virus genetic material used quickly to take over cell, then lysis occurs to release newly made viruses. Influenza and Ebola Lytic Viruses Lysogenic Viruses Lysogenic: virus nucleic acid “fuses” with the host cell’s until lysis (bursting) LATER. When infected cell undergoes cell cycle: replication of virus DNA with cell DNA many cells infected During this “dormant” period no illness is seen HIV and herpes Lysogenic Virus Protection Against Viruses ANTIBIOTICS DON’T WORK ON VIRUSES!!! Vaccines: Used as PREVENTION, NOT A CURE! Only useful against viruses that do not mutate and evolve (change) rapidly. HIV, common cold viruses and flu virus- DNA mutates rapidly. No permanent vaccine! Tamiflu is an antiviral medicine, but not reliable. HIV Devastating Africa 30 million + people have the disease Infects T cells of immune system Can lie dormant in our DNA for 10 years + Ryan White HIV Dormancy During dormancy, people look healthy, but can still spread the disease by: Sexual contact (including oral) Sharing needles Blood transfusions Organ transplant Baby to mother Blood to blood contact of any kind HIV video clip Other Viral Diseases HIV Common cold Chicken pox Measles Rabies Rubella Mumps Influenza (flu) Small pox Hepatitis Yellow fever Ebola