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NEU Microbiology Spring 2011 Lec 2
These flashcards go over all review material from chapter 2 (including the brief stuff from chapter 3)
28
Microbiology
Undergraduate 1
01/17/2011

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Term
If you get a new lens for your microscope with a numerical aperture of 1.2 instead of the old 0.6, did you improve your resolution? By how much?
Definition

A higher NA value results in improved resolution. Standard air has an NA value of 1.0 while special oil imersions have values of 1.5 (and these are very high resolution) so an increase in NA is better resolution. You improve the resolution by twice the old value

Term
Why is it easier to see Magnetospirillum bellicus, a purple phhototrophic bacteria, than E. coli under light microscopes?
Definition

E. coli has no pigment under normal circumstances so in order to see it under a light microscope it needs to be stained. M. bellicus already contains a purple pigment so it does not need additional staining

Term
How do plasmids differ from chromosomes?
Definition

A chromosome in prok cells generally consist of a single circular DNA molecule but plasmids also have small amounts of extra-chromosome DNA called plasmids that confer special properties

Term
Staphylococcus aureus will stain _______ with the traditional Gram stain.
Definition

Purple. Gram+ cells will turn purple under
Gram staining, it's just a matter of knowing whether or not the microbe is + or -

Term
Photoautotrophs get their energy from _______ and their carbon from ________.
Definition
Energy: light. Carbon: carbon dioxide
Term
What is Archaea?
Definition

Archaea is one of the two known domains of prokaryotes

Term
What is an autotrophan?
Definition
An autotrophan is an organism which is able to grow simply by using carbon dioxide and its sole carbon source
Term
What is the micriobiological definition of bacteria?
Definition

Bacteria is one of the two known domains of prokaryotes

Term
What is the cell wall?
Definition

The cell wall is a rigid layer present outside of the cytoplasmic membrane that confers structural strength on the cell and protection from osmotic lysis

Term
What is a chemolithotroph?
Definition

A chemolithotroph is an organism that obtains its energy from the oxidation of inorganic compounds

Term
What is a chemoorganotroph?
Definition

A chemoorganotroph is an organism that obtains its energy from the oxidation of organic compounds

Term
What is the definition of a chromosome?
Definition

A chromosome is a genetic element containing genes essential to cell function

Term
What are cyanobacteria?
Definition
Cyanobacteria are prokaryotic oxygenic phototrophs
Term
What is the cytoplasmic membrane?
Definition
The cytoplasmic membrane is the cell's permeability barrier and it also encloses the cytoplasm
Term
What is endosymbiosis?
Definition

Endosymbiosis is the process by which mitochondria and chloroplasts originated from descendants of bacteria

Term
What is the microbiological definition of a eukaryote?
Definition

A eukaryote is a cell that has a membrane-bound nucleus and which usually has other membrane-bound organelles

Term
What is the exact definition of evolution?
Definition

Evolution is the change in a line of descent over time leading to new species or variety within a species

Term
What is an extremophile?
Definition
An extremophile is an organism that grows optimally under one or more environmental extremes
Term
What is the Gram stain and how can you tell if a microbe is Gram + or -?
Definition

The Gram stain is a differential staining technique in which cells stain either pink (Gram -) or purple (Gram +)

Term
What are Gram + bacteria?
Definition

Gram + bacteria are a major phylogenic lineage of prokaryotic cells that contains mainly peptidoglycan in their cell walls. They stain purple under the Gram stain

Term
What are Gram - bacteria?
Definition
Gram - bacteria are prokaryotic cells that contain an outer membrane and some peptidoglycan in their cell walls (but typically not as much as Gram +). They stain pink under the Gram stain
Term
What is a heterotrophan?
Definition

A heterotrophan is an organism that requires organic carbon as its carbon source

Term
What is phylogeny?
Definition

Phylogeny is the evolutionary relationships between organisms

Term
What is a plasmid?
Definition

A plasmid is an extrachromosomal genetic element that is not essential for growth

Term
What is the definition of a prokaryote?
Definition

A prokaryote is a cell that lacks a membrane-enclosed nucleus and other organelles

Term
What is proteobacteria?
Definition

A proteobacteria is a large phylum of bacteria that includes many of the common gram - bacteria such as E. coli

Term
What is the definition of resolution in regards to microscopy?
Definition

Resolution is the ability to distinguish two objects as distinct and seperate under the microscope

Term
What is a virus?
Definition

A virus is a genetic element that contains either DNA or RNA and replicates in cells. They have an extracellular form

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