Microbiology Exam #1
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Microbiology Exam #1
Microorganisms include what?
Disease causing organisms
How long after the first bacteria was seen did it take to prove microbes caused disease?
What are the characteristics of Protozoa?
No cell walls (usually)
What do Helminths include?
What are B Vitamins essential for?
What is important about industrial microbes?
Man has harnessed them to produce useful things
How many species have been identified on Earth?
Van Leeuwenhoek is often called what?
The Father of Microbiology
What do Medical Microbes do?
What do our normal microbiota include?
Microbes, mostly bacteria, that live in or on us pemanently
Protists are what?
A grab bag of species that don't belong to other eukaryotic kingdoms
What ar some characteristics of Fungi?
Most microbes on Earth are what?
What are major groups of Fungi?
The study of Viruses
What do our normal microbiota do?
Crowd out pathogens
How many species of bacteria are there?
There are less species of what?
First living microbes were observed when?
How small are microbes?
Too small to be seen with the naked eye
Species in domain Eukarya can be assigned to one of what 4 kingdoms?
Molds & Mushrooms are what?
Yeasts are what?
What do industrial microbes do?
Produce chemicals (citric acid), Foods (bread, yogurt), Medical Products (insulin, antibiotics)
Vitamins we absorb are produced by what?
What vitamins are produced by intestinal bacteria?
Several B Vitamins
Study of parasites
What are the characteristics of Archaea?
No Peptidoglycan in cell walls
Parisitologists usually study what?
What do photosynthetic microbes include?
What are the characteristics of Helminths?
no cell walls
What are major groups of protists?
What is Vitamin K necessary for?
What are the characteristics of Bacteria?
Cell Walls with Peptidoglycan
What are the characteristics of Algae?
Cell Walls have Cellulose
What are major groups of Anamilia?
Study of Bacteria
What are environmental microbes?
What are the 4 most abundant elements in living organisms?
Hydrogen, Carbon, Nitrogen, Oxygen
What percent of weight is made up by the 4 elements in living organisms?
What element is the single most abundant by weight in living organisms?
When do molecules form?
atoms become held together by chemical bonds
Chemical bonds can be... ?... or ?...
Covalent (share e-)
Ionic (opposite charges)
Weak, temporary bonds
Why is water a good solvent?
Forms plentiful hydrogen bonds
What helps DNA and proteins keep their shape?
Ph is used to indicate what?
How much hydrogen there is in a solution
Increasing H+ ...
Acidic solutions have... ?
Higher H+ concentration
Lower H+ concentration
Important for structure and used as energy sources?
Carbohydrates can be... ?
Chitin is what?
Polymer of modified glucoses
Glucose can be used as what by nearly all organisms?
The breakdown of glucose releases energy that can be recaptured to form...
Breaking the bonds in ATP provides energy for what?
Numerous cellular activites & chemical reactions
Includes fats/oils, sterols, phospholipids
Broad, fat lipids found in cell membranes to help stabilize it
Who observed the first microbe?
Where do saprophytes get their nutrients?
dead and decaying material
Where do parasites get their nutrients?
What are ions?
Number of protons determine what?
The number of neutrons determine what?
What do electrons deermine?
the chemical properties of an atom
What part of an atom takes part in a chemical reaction?
What do environmental microbes do?
Decompose organic waste
Study of Fungi
Each microorganism has what?
Genus & species name
All species on Earth belong to one of what three domains?
What species are prokaryotic?
Bacteria & Archaea
How many elements are required by living organisms?
Major sterol in the cell membranes of animals
Major sterol in the cell membranes of fungi
What species cell membranes do not have sterol?
What proteins are important in metabolism?
Why are proteins important?
Transport (nutrients across membrane)
What are proteins?
Polymers of amino acids
What is the covalent bond that holds amino acids together?
How many amino acids are found naturally in living organisms?
The 3D shape of proteins is essential for what?
What is denaturation caused by?
What does denaturation cause?
loss of funcion
3D shape is lost
What are nucleic acids?
polymers of nucleotides
What forms the backbone in DNA & RNA?
Sugar and Phosphate
Where does the base of a protein point?
Away from the strand
Bases of DNA?
What does DNA do?
Carries info to make protein & carries cells genetic info
Assists making proteins
What holds together the strands of DNA?
ATP is converted to ADP which...
What is ATP?
energy provider in cells of all organisms
Where is ATP produced in Eukaryotes?
obj. lens x ocu. lens
What is resolution?
ability to see small details
What are fluorescent microscopes used for?
Quickly identify microbes in complex samples (like clinical specimens)
What is a negative stain?
Stains slide and not capsule - the unstained spheres will indicate presence of capsule
How are specimens prepared for a scanning electron microscope?
coated with a heavy metal
Why is an acid-fast stain good for mycobacterium?
mycobacterium have a think waxy layer, mycolic acid, that resist penetration
How can capsules be seen?
using a negative stain
One species of mycobacterium causes tuberculosis the other causes what?
Magnets are used as what to direct the beam of electrons?
How does an electron microscope work?
uses electrons instead of light to illuminate the object
Why is oil immersion used?
because light refracts when it exits slide and misses small lens
When is a darkfield microscope useful?
when cells are alive or unstained
What does immersion oil do?
keeps light from refracting
Why are light microscopes used?
What makes the difference in Gram + and Gram - ?
thick layer of peptidoglycan makes it hard to remove crystal violet
An acid-fast stain is good for what species?
In-phase light appears...?
When it comes to finer detail a phase-contrast microscope is better than what?
What is the magnification of a transmissioin electron microscope?
10,000 - 100,000x
What kind of specimens must be used for a scanning electron microscope?
Electron microscope images are what color?
black/white ... color is added by computer software
What gives better resolution?
shorter wavelengths of light
Why is it difficult to use unstained specimens on a brightview microscope?
Bright background and almost clear cell
What is the field of view on a brightfield microscope?
What is the limit of magnification on light microscopes?
What is the magnification on a scanning electron microscope?
1,000 - 10,000x
Short wavelengths of electrons give what in electron microscopes?
What kinds of specimens are used in transmission electron microscopes?
What is a specimen that would be viewed under a fluorescent microscope?
How does a scanning electron microscope work?
beams of electron scan specimen surface and light reflects around it
Why are endospores very tough survival structures?
they resist penetration by stain so heat loosens coat and allows stain to enter
How do electron microscopes work?
electron sensors detect electron patterns and put image on a screen
What does a phase-contrast microscope do?
shows differences in phase of light going through specimen
What is a capsule?
slimy layer of polysaccharides that surrounds cells of some bacteria
Flagella is coated with what and why?
mordant - they are usually too thin to be seen with a light microscope and mordant thickens it enough to be seen
In fluorescence microscopes cells are stained with what?
What does an endospore stain require?
heat to drive stain into endospore
How do transmission electron microscopes work?
electrons pass through specimen and allows internal view of structure
How do Gram Stains work?
use multiple stains so different cells appear differently at the end
How does the Gram Stain process work?
Crystal Violet enters cells
Iodine enters cells and binds to crystal violet
Alcohol enters and removes crystal violet
Safrinin stains rest of cells
Phase-contrast microscope increases... ?
Gram Stains use what 4 stains?
A Gram Stain is what kind of stain?
a differential stain
What is done to the specimen for a transmission electron microscope?
strained with a heavy metal to make it more dense
What is the resolution limit on light microscopes?
What size are most bacterial cells?