Bacteria=Prokaryotes  ProkaryotesEukaryotes  No organelles except Lots of organelles ribosomesINCLUDING  NO NUCLEUS!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 CO 2, water, nitrogen, and phosphorus

Useful Bacteria Nitrogen fixation- soil bacteria take nitrogen gas from the air (N 2 ) and change it into a useable form that plants can absorb (NH 3 - ammonia.) Plants use the nitrogen to produce their proteins and DNA. Some bacteria are photosynthetic and also provide oxygen NH 3 N2N2 YUMMY! Bacteria

Useful Bacteria  Food-- yogurt, olives, pickles, chocolate  Drugs -- insulin production  Clean up oil spills  Animal digestion and vitamins, including our own  Microbe Discovery Movie 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 substance produced by a microbe that slows the growth of other microbes. MOLD BACTERIA

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.) Each paper disk has antibiotics on it. Which antibiotic is more powerful? BACTERIA

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 MovieMovie  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 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 HIV video clip

Other Viral Diseases  HIV  Common cold  Chicken pox  Measles  Rabies  Rubella  Mumps  Influenza (flu)  Small pox  Hepatitis  Yellow fever  Ebola