Microbiology Microbiology- the study of very small,

microscopic organisms Bacteria Fungi Viruses Protists Etc.

Bacteria=Prokaryotes Prokaryotes Eukaryotes No organelles except Lots of organelles

ribosomes INCLUDING 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!

Ribosomes- the protein making factories of all cells that take mRNA and translate it into the amino acids of a protein

Bacterial Structure

Identifying Prokaryotes Shape – rod, spherical, spiral Chemical nature of cell walls Movement – flagella, lash, snake, spiral

forward, glide on slimelike material Obtain energy – heterotrophs or autotrophs

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 - : bacteria that stain pick and

are generally NOT affected by antibiotics i.e. E. coli

Gram +: bacteria that stain purple do to a thick cell wall and are affected by antibiotics i.e. S. pneumoniae

Bacterial Reproduction Binary fission- bacteria’s

process of reproduction where 1 becomes 2. Results in clones Colony- 1000’s of

bacteria that result from one undergoing binary fission

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 (NH3- ammonia.)

• Plants use the nitrogen to produce their proteins and DNA.

• Some bacteria are photosynthetic and also provide oxygen NH3

N2YUMMY!

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

Harmful Bacteria Pathogen- disease causing organisms. Pathologists -scientists who study pathogens. Not many bacteria are pathogenic— ONLY 1%! Disease Transmission:

a.) Waterb.) Airc.) Foodd.) Animals/Insectse.) 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.

GROWTH CURVE

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.

Controlling Growth Antibiotics

Antibiotic resistance Sanitizing--Antiseptics and Disinfectants Freezing Cooking Pasteurizing- The act or process of heating a beverage or other food, such as milk or

beer, to a specific temperature for a specific period of time in order to kill microorganisms that could cause disease, spoilage, or undesired fermentation.

Vaccination Dehydrating- removing water from food, thus inhibiting the growth of

microorganisms (enzymes) and bacteria by the circulation of hot, dry air through the food.

Antibiotics Alexander Fleming - In 1928, while working on influenza

virus, he observed that mould had developed accidently on a staphylococcus culture plate and that the mould had created a bacteria-free circle around itself.

Mold on his Petri dish had a zone of inhibition- area in which bacteria didn’t grow.

Mold released the antibiotic penicillin

Antibiotic=against life; any substance produced by a microbe that slows the growth of other microorganisms.

MOLD

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

Each paper disk has antibiotics on it.

Which antibiotic is more powerful?

BACTERIA

Antibiotic Resistance Movie

Antibiotic resistance- a situation in which some 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 Pasteurization- using

heat to kill bacteria in liquids.

Dehydrating Dehydration- removal of water from a substance How would this control the growth of bacteria?

Vaccination Vaccination- a shot, pill, or mist that prevents you

from getting a 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. tetanus.)

Vaccination Can use weakened (attenuated) bacteria or viruses MOSTLY use parts of bacteria or viruses—

acellular Vaccine video