Microbiology Part 1
description
Transcript of Microbiology Part 1
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