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Microbiology Study Guide Cheat Sheet by

Study Guide for Microbiology

Chapter 1 Humans and the Microbial World

What is microb­iology?
study of life too small to be seen by unaided eye (microbial world)
How did people figure out that there were microbes?
Develo­pment of the micros­cope.
Define Domain
The highest level in biological classi­fic­ation. There are 3 domains: Bacteria, Archaea, & Eukarya.
Define Eukaryote
Organism composed of 1 or more eukaryotic cells; members of the domain Eukarya & eukary­otes.
Define Eukaryotic Cell
Cell type charac­terized by a membra­ne-­bound nucleus
Define Prion
An acellular infectious agent consisting only of protein.
Define prokaryote
single­-celled organism consisting of a prokar­yotic cell; members of the domains Bacteria & Archaea are prokar­yotes.
Define prokar­yotic cell
Cell type charac­terized by the lack of membra­ne-­bound nucleus.
Define Viroid
An acellular infectious agent consisting only of RNA
Define Virus
An acellular infectious agent consisting of nucleic acid surrounded by a protein coat.
Define Sponta­neous Generation
Life arose from non-living matter
In 1749, John Needham produced results that ____ sponta­neous generation when he showed that broths that had been boiled & then sealed with a cork ____.
support; could still give rise to microo­rga­nisms.
Lazzaro Spalla­nzani's experiment of 1776 showed that flasks of broths that had been boiled for long periods of time & sealed tight ____.
remained free of microo­rga­nisms.
Francesco Redi first disproved the theory of sponta­neous generation by showing that ___.
worms only appear on decaying meat has been exposed to flies.
Tyndall & Cohn's experi­ments in the 1870s showed of a heat-r­esi­stant form of bacteria called a(n)
The Golden Age of Microb­iology is the period in which...
many diseas­e-c­ausing microo­rga­nisms were discov­ered.
The principle that microo­rga­nisms cause certain diseases is called the ___ Theory.
The property of endospores that led to confusion in the experi­ments on sponta­neous generation is their ___.
heat resistance
If all prokar­yotes were eliminated from the planet,
all animals would die
All of the following are emerging infectious disease except...
All of the following are biological domains except...
Which name is written correctly?
Staphy­loc­occus epider­midis
Members of which pairing are most similar in appearance to each other?
Archaea & Bacteria
contain both protein and nucleic acid
Antonie van Leeuwe­nhoek could not have observ­ed...
The Scientific Method
Scientific Method includes (1) observing occurrence & asking a question about that situation; (2) developing a hypothesis that explains the occurrence & devising an experiment that tests the hypoth­esis; (3) doing the experi­ment, collecting the data, & drawing conclu­sions; & (4) commun­icating the results, methods, & conclu­sions.
What is a scientific theory?
An explan­ation supported by a vast body of experi­mental evidence.
Define Biogenesis
The production of living things, as opposed to sponta­neous genera­tion.
Early Experi­ments
The experi­ments of John Needham supported the idea of sponta­neous genera­tion, while those of Lazzaro Spalla­nzani did not.
Experi­ments of Pasteur
Pasteur disproved sponta­neous generation & supported what is now known as the theory of biogenesis.
Experi­ments of Tyndall
John Tyndall showed that some microbial forms are not killed by boiling. He & Ferdinand Cohn discovered endospores, the heat-r­esi­stant forms of some bacteria.
Commercial Benefits of Microo­rga­nisms
Microo­rga­nisms are used in the production of bread, wine, beer, & cheeses. They are also used to degrade toxic pollutants and to synthesize a variety of different useful products. Biotec­hnology depends on members of the microbial world.
Define Biotec­hnology
The use of microb­iol­ogical & bioche­mical techniques to solve practical problems & produce valuable products.
Microbes as Research Tools
Microo­rga­nisms are wonderful model organisms to study because they have the same fundam­ental metabolic & genetic properties as higher life-f­orms, & they grow rapidly on simple, inexpe­nsive growth media.
Define Bacteria
Bacteria are single­-celled prokar­yotes that have peptid­oglycan in their cell walls.
Define Coccus
sphere­-shaped bacterial cell.
Define Rods
Cylind­er-­shaped bacterium; also called a bacillus
Define vibrio
short, curved, rod-shaped bacterial cell
Define spirillum
curved rod-shaped bacterial cell that is long enough to form spirals
Define Spiroc­hetes
Long, helical bacteria that have flexible cell wall & endofl­agella
Define Archaea
single­-celled prokar­yotes
Define Fungi
single­-celled yeasts & multic­ellular molds & mushrooms; they use organic compounds as food
Define Algae
single­-celled or multic­ell­ular, & use sunlight as an energy source
Define Protozoa
typically motile single­-celled organisms that use organic compounds as food.

Chapter 3 Cells & Methods to Observe Them

Define Capsule
a distinct, thick gelatinous material that surrounds some microo­rga­nisms
Define chemotaxis
movement of a cell toward or away from a certain chemical in the enviro­nment
Define Cytopl­asmic Membrane
A phosph­olipid bilayer embedded with proteins that surrounds the cytoplasm & defines the boundary of the cell
Define Endospore
An extrao­rdinary resistant dormant cell produced by some types of bacteria
Define Flagellum
A type of structure used for cell movement
Define Gram-N­egative Bacteria
Bacteria that have a cell wall charac­terized by a thin layer of peptid­oglycan surrounded by an outer membrane; when Gram stained, these cells are pink
Define Gram-P­ositive Bacteria
Bacteria that have a cell wall charac­terized by a thick layer of peptid­ogl­ycan; when Gram stained, these cells are purple
Define Lipopo­lys­acc­haride (LPS)
Molecule that makes up the outer layer of the outer membrane of Gram-n­egative bacteria
Define Peptid­oglycan
a macrom­olecule that provides strength to the cell wall; it is found only in bacteria
the gel-like material that fills the region between the cytopl­asmic membrane & the outer membrane of Gram-n­egative bacteria & the cytopl­asmic membrane & peptid­oglycan layer of at least some Gram-p­ositive bacteria
Define Pili
cell surface structures that allow cells to adhere to certain material; some types are involved in a mechanism of DNA transfer
Define Plasmid
Extrac­hro­mosomal DNA molecule that replicates indepe­ndently of the chromosome
Define ribosome
structure involved in protein synthesis
Transport systems
Mechanisms cells use to transport nutrients and other small molecules across the cytopl­asmic membrane
Which bacterial cell component provides the best barrier for preventing most molecules from passing through it?
Cytopl­asmic membrane
Endotoxin is associated with...
Gram-n­egative bacteria
The "­O15­7" in the name E. coli O157:H7 refers to the type of O antigen. From this inform­ation you know that E. coli
Is Gram-n­egative
Elimin­ating which structure is always deadly to cells?
Cytopl­asmic membrane
If you interfered with the ability of a Bacillus species to form endosp­ores, what would be the result? The bacterium would no longer be...
able to withstand boiling water
If a virus mimics a ligand that normally partic­ipates in recept­or-­med­iated endocy­tosis, the virus might..
be take up by the cell
The antibiotic erythr­omycin prevents protein synthesis in bacterial cells. Based on this inform­ation, which of the following might be targeted by the drug?

Chapter 3 Cells & Methods to Observe Them Cont.

The antibiotic erythr­omycin prevents protein synthesis in bacterial cells. Based on this inform­ation, which of the following might be targeted by the drug? 2. 70s ribosomes, 4. 50s ribosomal subunit
2, 4
If a eukaryotic cell were treated with a chemical that destroys tubulin, all of the following would be directly affected except
Which of the following is most likely to be used in atypical microb­iology labora­tory?
Bright­-field microscope
When a medical techno­logist wants to determine if a clinical specimen contains a Myobac­terium species, which should be used?
Acid-fast stain

Chapter 4 Dynamics of Microbial Growth

Define Biofilm
Polyme­r-e­ncased community of microo­rga­nisms
Define Chemically Defined Medium
A culture medium of exact chemical compos­ition; generally used only for specific experi­ments when nutrients must be precisely controlled
Define Complex Medium
A culture medium that contains protein digests, extracts, or other ingred­ients that vary in their chemical compos­ition
Define Differ­ential Medium
A culture medium with an ingredient that certain microo­rga­nisms change in a recogn­izable way; used to differ­entiate microbes based on their metabolic traits
Define Expone­ntial (Log) Phase
Stage in the growth curve during which cells divide at a constant rate; generation time is measured during this period of active.


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