Topic 1 Flashcards
Define microbiology
The study of microorganisms or microbes - living things that are generally too small to be seen with the unaided eye
What is microbiology?
Some microbes are pathogenic (disease causing), the vast majority are beneficial or harmless
Give an example of bacteria
Escherichia coli (E.Coli)
Give an example of a fungi
Candida Albicans (Yeast)
Give an example of protists
Giardia
Give an example of animal parasites
Tapeworm
Give an example of a Virus
Influenza virus H1N1
Give an example of a prion
Creutzfeldt-Jakob disease
What does a microbiologist do?
Food (Fermentation), Biotechnology (Pharmaceuticals), Energy (Bioremediation)
What is the importance of microbes?
Many are photosynthetic; they produce much of the oxygen we breathe (ex: Cyanobacteria)
They form the base of most food chains (ex: Diatoms)
What has a microbe ever done for me?
- Decomposers (return material to the environment)
- Nutrient Cycling (nitrogen, carbon & sulphur cycle)
What do we harness bacteria for?
- Food (Dairy and alcohol)
- Sewage treatment
- Bioremediation
- Cloning genes and fragments of DNA
- Making antibiotics and pharmaceuticals
- Industrial processes
How do microbes help form cheese?
- Bacterial cultures generate lactic acid which transforms milk into cheese
- Fungi may add to the flavour
How do microbes form yogurt?
Bacteria acidify and curdle milk
How do microbes form bread?
Fungi (yeast) make CO2 that causes the bread to rise
How do microbes make ethanol?
Yeast make CO2 and ethanol as a by-product of fermentation
Define symbiosis
It is “living together” - a biological relationship
Many microbes act as symbionts
What are the three types of symbiosis relationships?
Mutualism, Commensalism, Parasitism
Define mutualism
A symbiotic relationship where both organisms benefits
Ex: Clownfish living in a sea anemone
The anemone protects the clownfish and the fish eats parasites that can harm the anemone
Define Commensalism
A symbiotic relationship where one benefits, the other is unaffected
Ex: Remoras living on a shark
The remoras are benefitted while the shark is unaffected
Define parasitism
A symbiotic relationship where one organism benefits, the other is harmed
Ex: Flea on a dog
The flea benefits while the dog is harmed
What is Microbial Flora (Microbiota)?
They are good microbes. Normal flora can prevent the growth of pathogens. Some normal microbiota produce vitamins (Ex: folic acid and vitamin K)
Do parasites kill the host?
Some do, but most of the time they do not kill the host
Define parasitism
Parasitism are bad microbes
What are the two strategies parasites may use?
- Cause minimal problems for the host (allows them to stay put for an extended period)
- Reproduce very rapidly and move on - may be fatal
What are bubos
Bubos are swellings that were caused by bubonic plague in the lymph nodes (armpits)
What was “The Black Death”
The black death were infected tissue of extremities that dies (goes necrotic) and turns black
What are the three forms of the plague
- Bubonic (Lymph)
- Septicemic (Blood)
- Pneumonic (Lungs)
What are the three ways you can catch the plague
- Handling dead bodies or rodents/animals that have died from the plague
- Being bit by a rodent
- Airborne?
Which type of plague is the most fatal?
Septicemic is 99% fatal
Describe the pattern of transmission of the plague
- A flea bites a mouse and draws some of their blood
- The microbes multiple in the stomach of the flea
- The flea bites a human
Define epidemiology
The study of how disease spreads
Where does yersinia pestis (bacterium) live
In the gut of a flee
What was the Black death?
It occurred over 5 years in Europe, it killed approx 25 million people (1/3 of Europes population), also known as the plague
What did Robert Hooke discover?
- Observed tiny ‘boxes’ in cork which he named “cells”
- Perfected microscopes
What did Antonie Van Leuuwenhoek discover?
“Animalcules”
- Created the first microscopes to look at cells
- He saw giardia and the green microbes found in swamp water under the microscope
How do we study microbes?
Science
- In its ‘purest’ form, it’s the process of
organizing empirical (vs. theoretical)
data into a useable body of knowledge
What is a hypothesis?
- a reasonable explanation or ‘best guess’
- a tentative answer to a well-framed question
- an explanation on trial, it can be used to make a prediction that can be tested
A hypothesis must be (2)
Testable and falsifiable
What is the scientific process
- Hypothesis (and predictions)
- Experiment (and collect data)
- Conclusions - is your hypothesis falsifiable or supported?
- Observations, Questions
An experiment must
be capable of falsifying the hypothesis
What is the experimental variable?
the factor that is changed/manipulated
What is the experimental group?
Subsets of organisms etc. for which one or more factors are changed/manipulated
What are the control groups (positive and negative)
Outcome to which you compare your changes in your manipulated (experimental) group
William of Occam believed
the simplest answer should be tested first
Positive Control
Is not always done
It is used to demonstrate that the system being studied is capable of generating a change in the dependent variable (important to do if we get negative results)
The Panama Canal
Many workers died of malaria and yellow fever
Is yellow fever spread by mosquitoes?
Yes, it was tested on humans
The mosquito was proposed as a vector by Juan Findlay and later confirmed by Walter Reed
What is the Finlay-Reed experimental volunteers?
Building 1 was exposed to fomites
Building 2 was exposed to potentially infected mosquitoes and air shared by group B, not mosquitoes
What did Finlay-Reed find out from the Fomite experiment? (2 things)
Mosquitoes had to carry the virus for a little while (mosquitoes were not immediately effected) Ex: a few days, for the virus to carry out its life cycle
2nd ____?
What is a fact?
Very well established and agreed on (ex: Paris is the capital of France), it can be subjective
What is a theory?
very specific observation, usually a math equation or ratio (ex: laws in chemistry), tiny, may be a part of a theory
What is a law?
A big model with lots of evidence that supports it. Ex The pancreas produces insulin is a theory or evolution
What is spontaneous generation (abiogeneses)
The notion that living organisms arise from non-living matter. A “vital force” in the air forms life
What is biogenesis
The alternative hypothesis, that living organisms only arise from pre-existing life
What is spontaneous generation (abiogeneses)?
The notion that living organisms arise from non-living matter. A “vital force” in the air forms life
What is biogenesis?
The alternative hypothesis, that living organisms only arise from pre-existing life
What is the cell theory?
- All living things are made up of cells
- All cells come from parental cells
Who developed the cell theory?
Matthias Schleiden & Theodor Schwann
How did Francesco Redi test spontaneous generation?
He demonstrated that covering meat jars with gauze prevented the ‘generation’ of maggots/flies.
What quote Louis Pasteur known for?
“Do not put forward anything that you cannot prove by experimentation”
What was Louis Pasteur known for?
- Known as the “father of biology”
- Showed that fermentation was caused by microbes
- Demonstrated that spoilage bacteria could be killed by heating for short periods - Pasteurization
- Showed that rabies was not caused by bacteria
What did Louis Pasteur demonstrate
Slide 55 half done
He demonstrated that microorganisms are present in the air
Fermentation is used to make
Alcohol
Define pasteur
To heat an item short enough that you kill the active bacteria but not long enough that you change the food
What is the germ theory of disease?
The findings of Pasteur and Koch led support to “The “Germ Theory of Disease” – microbes are the causative agents of disease
What is Robert Koch known for?
- Showed that a bacterium causes anthrax
- Used Koch’s postulates to show that a specific microbe causes a specific disease.
What are Koch’s postulates used for?
Used to test what causes a new disease
Describe the steps of Koch’s Postulates
- Isolate microbe from an infected animal
- Grow microbes as a pure culture and identify/characterize pathogen
- Infect new host
- Observe the same disease symptoms
- Isolate and identify the microbe
What was Ignaz Semmelweis known for?
Discovered that hand washing and cleaning equipment dramatically reduced childbed fever in obstetrical clinics.
What was Joseph Lister known for?
Used a chemical disinfectant to prevent surgical wound infections after looking at Pasteur’s work
What was Edward Jenner known for?
- Inoculated a young boy with cowpox virus. The boy was then protected from smallpox
- Termed vaccination
- The protection is called immunity
What are the 3 key concepts?
- Microbes are everywhere, some are harmful to us and many are beneficial
- Many disease, such as bubonic plague, have shaped human history
- The contributions of Louis Pasteur, Robert Koch and others led to the germ theory of disease
We use microbes for our benefit for:
- Dairy and alcohol
- Sewage treatment
- Bioremediation
- Cloning genes and fragments of DNA
- Making antibiotics and pharmaceuticals (ex: Pen G)
- Industrial processes
- Immunity
- Recycling elements (nitrogen, sulfur, copper)
- Producing ethanol and acetone (and other chemicals)
What is the cell theory?
- All living things are made up of cells
- The cell is the basic unit of life
- All cells come from parental cells
Where were the maggots coming from in Redis experiment?
Flys were laying eggs which hatched into larva –> maggots
Why did Pasteur use a swan-necked flask?
It allows air to get inside the container but not bacteria. Bacteria can’t make it all the way to the broth
What diseases can you use Koch’s postulates for?
Any disease you can isolate and grow it as a pure culture
Examples of diseases you can not use Koch’s postulates to test
Herpex simplex, Syphillis, and Prions but you can not make a pure culture
Define microbiota
The group of microbes that normally inhabit the surfaces of the body without causing disease
Define biogenesis
The synthesis of substances by living organisms
Define pathogen
A microorganism capable of causing disease
Define symbiosis
A continuum of close associations between two or more organisms that range from mutually beneficial to associations in which one member damager the other member
Define immunity
The ability of an organism to resist a particular infection or toxin by the action of specific antibodies or sensitized white blood cells
Describe Redis experiment
Demonstrated that covering meat jars with gauze will prevent the ‘generation’ of maggots/flies. You would take three jars and fill them each with a piece of meat. The first flask would remain unsealed, the second flask would be sealed shut, and the last flask would be covered with gauze and secured with a rubber band. The unsealed flask would show flies on the meat and maggots. The second flask would show no flies in the jar. The last flask would show flies sitting on top of the gauze, but not inside the flask. This shows that meat will not spontaneously produce maggots.
Describe the steps of Koch’s postulates
Koch would get mice, affect them with anthrax, he would make sure they have the symptoms of the disease, draw blood, look at microbes, isolate a microbe (the one he thought was causing the symptoms), he would then grow the microbe on a petridish, microbes would multiply (become a colony), take that colony and put it on a new plate (becomes a pure culture), make a sample of that and inject it into a healthy mouse, and then see if that mouse gets the same symptoms as the sick mouse, extract blood/fluids from the second mouse and make sure that microbe is there
Describe the experiment done by Louis Pasteur
Pasteur boiled bone broth in various flasks for one hour to sterilize it and allowed it to cool, drawing in fresh air. He placed broth in an open contained which became contaminated with bacteria, another closed with a cotton plug which remained sterile and the third was placed open but with a swan neck that also remained sterile
