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Microbes live in us, on us and nearly everywhere around us. What activities are microbes involved in?
- Decay of dead plants and animals (organic matter). breaks down complex chemicals into basic building blocks that can be reused. If not, all carbon & nitrogen & oxygen (building blocks of life) would be tied up and unavailable for new life.
- Food production: baking, wine and beer (yeast); cheese and yogurt (molds/fungi); vinegar (bacteria)
- Antibiotics: Penicillin (Penicillium), Chloramphenicol (Streptomyces), bacitracin (Bacillus)
- Vaccination: smallpox, diphtheria, anthrax
Why are microorganisms useful in many different research laboratories (such as ecology, biochemistry, evolution and genetics)?
*Immunology, virology (study of viruses), chemotheraphy to kill bacteria, and genetics - bacteria change its nature, antibiotics, vaccines
- o Produce biochemicals (hormones and regulatory proteins) in large quantities which are pure and non-antigenic
- o (won’t produce antibodies because not recognized as foreign).
- o Human insulin, interferon, and growth hormone are regulatory proteins produced in bacteria.
- Photosynthetic microbes
- o are responsible for converting light energy (Sun) into chemical energy (food). Algae are the lowest element of the food chain in water.
- o Small and rapidly reproduce.
- o Useful for long term studies of chemical effects.
- o Simple genetics make good research model for life processes
- o (Protein refolding, fermentation, DNA replication) and mechanisms of inhibition of these processes.
- o Source of chemicals used in research
- o (reverse transcriptase (mRNA to cDNA),
- o restriction nucleases (specific DNA/RNA cleaving enzymes used in recombinent genetics, and
- o DNA polymerase (replicates DNA)).
The English scientist Robert Hooke coined the term cell because the small boxes he saw in the microscope reminded him of a monks room. What is the cell theory that was later proposed?
All living things are composed of cells. Applies to all cellular organisms, but not to viruses.
What is the germ theory of disease? What does it say?
Microbes could cause disease.
*Microorganisms (germs) can invade other organisms and cause disease.
5. In a Gram stain, what are the various reagents used, and what is the purpose of each reagent?
- -Crystal Violet: Purple stai, primary dye
- -Iodine: Lugol's iodine is that mordant - causes irreversible association of dye with bacterial structure fixative
- -Water: Rinse excess stain of the water
- -Alcohol: 95% Alcohol wash - for decolorizer. Extracts the lipid of gram - bacteria so they are porous and don't retain CV-RNA sugar complex like gram + bacteria.
- -Safranin: Red counterstain stains bacteria that do not retain crystal violet complex after decolorizing so ou can see them.
Koch's postulates. What was their purpose?
Devised "Koch’s Postulates" (4 steps to demonstrate microbe etiology: the study of the cause of disease).
- I. Organism found in every case of disease and not in healthy individuals
- II. Must be isolated and laboratory grown in pure culture
- III. Must reproduce disease when inoculated into healthy susceptible animals
- IV. Organism must again be isolated from newly infected animal and laboratory grown in pure culture.
First to isolate bacteria in pure culture by dilution in broth. Discovered the causative bacterium of TB, cholera, and anthrax
Purpose: Infectious disease is caused by a single organism. Koch's implied one organism-one disease.
To design a good experiment, an investigator must consider all variables that might affect the outcome. What is a variable?
A variable in an experiment is a quantity or an attribute whose value may vary over the course of an experiment. There are independent and dependent variables. The independent variable is the one being manipulated by an experimenter
. The dependent variable is the the variable upon which the effects of manipulating the independent variable are seen/observed.
- Independent variable - number of daily calories
- Dependent variable - weight
In an experiment, one may wish to examine the effect of the number of daily calories on weight. Therefore, the experimenter (you) would manipulate the number of daily calories and see the change in weight over the course of weeks/months/years
What sort of organisms are considered microbes?
- The first group:
- * Bacteria
- * Arachaea
- The second group:
- * Protists
- * Microscopic Animals
- * Fungi
- * Microscopic Plants
- 1886 Haeckel proposed a third kingdom "Protista" to include all unicellular organisms. Microbiology includes the study of Algae, Bacteria, Fungi, Protozoa, Rickettsiae and Viruses
- Microbes (Microorganisms) are classified in the following types. The first group consists of the Prokaryotes: * Bacteria * Arachaea The second group is made up of the Eukaryotes: * Protists * Microscopic Animals * Fungi * Microscopic Plants Prokaryotes are organisms that lack a cell nucleus and other "organelles", which are specialized parts of the cell that carry out specific functions and usually are separated from the rest of the cell by a membrane. This group includes bacteria and arachaea. Arachaea used to be considered just a different type of bacteria, but based on their RNA, scientists now know they developed separately. Study of them as a separate group is just beginning and there is still much to know about the differences and similarities between them and bacteria. Eukaryotes differ from Prokaryotes in that they do have cell nuclei separated within the membrane structures of the complex cells. There are also other specialized and membrane-bound structures in Eukaryotes which are the "organelles". Examples of organelles are: Mitochondria, Chloroplasts, and Gogi bodies. Eukaryotes also differ from Prokaryotes in how their cell division works. Most living organisms, including animals and humans, are Eukaryotes. The Eukaryotes that are microbes are the: Protists: Protozoa (one-celled animal like organisms), Protophyta (plant-like organisms that are made up mostly of one-celled algae), and fungus-like protists such as plankton, planarian, and amoeba. Microscopic Fungi: Baker's yeast, Fission yeast, and microscopic pathogenic yeasts (such as Candida albicans). Microscopic Plants: One of the largest groups of microscopic plants are the by Algae. There are around 6000 species of Green Algae and most, but not all, are microbes. Viruses are not considered microbes by scientists in this area of microbiology since they are not alive, they are inanimate particles that function similarly but are not technically microbes or living organisms. And, they are smaller than microbes, since they are sub-microscopic, requiring electron microscopes to visualize.
Define the following:
- Pasteurization: Mild heat killing the proces that kills most disease causing bacteria. Saved wine industry in France (losses due to wild yeast and bacteria on the grapes). Routinely used on milk today.
The first person to use a microscope to observe living cells was ____________
What are each of the following people famous for doing? Robert Hooke Matthias Schleiden Anton van Leeuwenhoek Louis Pasteur
Why is the period from 1874 to 1917 is generally referred to as the Golden Age of Microbiology?
Proteins are chains of ______ that sometimes function as________
In order to become an ion, an atom of chlorine must
Thethree fundamental particles of the atom are
When 5 grams of glucose is dissolved in 100 mL of water, the water is the ________ and the glucose is the ________.
Chemical bonds found in living organisms normally include
Describe the following reactions:
Organicmolecules with the same molecular formula but different structures are
Describe resolution as it pertains to microscopy,
Whenlight passes through an object, ________ of the light has occurred.
Whenlight rays pass into an object but do not emerge, ________ has taken place.
Explainthe index of refraction as it pertains to microscopy.
Thelens closest to your eyes during a microscopic examination is
To calculate the total magnification of a light microscope you must know
Explainthe term “parfocal” as it pertains to microscopes.
Describe how a simple stain works.
In a properly executed Gram stain, Gram positive organisms appear ________while Gram negative organisms appear ________.
Why do basic dyes attach to most bacterial surfaces?
The stains used in the Ziehl-Neelsen acid-fast stain are
A small comma shaped bacteria is described as being a ________.
Bacteriawhich show a wide variety of shapes within a single species are said to be
Extrachromosomal DNA in prokaryotic cells can be found in the form of
Which cellular structures can be found in both prokaryotic and eukaryotic cells?
Howdoes Penicillin control the growth of bacteria?
Endosporesare typically found in the genera _______________
Bacteriawith flagella all over their surface are said to be ___________
How domolecules behave during diffusion?
Theshape of a bacterial cell is determined (and maintained) by the ___________
What is the purpose of endocytosis?
The metric system was devised by
What are three reasons the metric system is superior to the English/Avoirdupois measurement system.
Thereare _____ Kingdoms in the taxonomic system in current use
How isa sample of Streptoccus growing with a green ring on blood agar reported?
You are using a spore stain to examine a culture that MIGHT be Anthrax (Bacillus anthracis). You know that if spores are present they will stain ___________ (what color?)