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micro unit 2 exam
unit 2 exam
67
Microbiology
Undergraduate 2
10/08/2014

Additional Microbiology Flashcards

 


 

Cards

Term
What substances can damage the plasma membrane?
Definition

alcohol

detergent

polymyxin antibiotics

Term
Why is the plasma membrane a good target for antibiotics?
Definition
  • disrupts the transport of substances across the membrane
  • leakage causes cell death
  • disrupts the electronic transport chain which produces ATP
Term

How do salty foods prevent the growth of bacteria?

 

Definition
Hypertonic environments, the cell shrinks and water moves out.
Term
What antibiotic/substances can damage Gram-positive cells?
Definition
  • penicillin
  • lysozyme
  • detergents
Term

What antibiotic/substances can damage Gram-negative cells?

 

Definition
  • streptomycin
  • chloramphenicol
  •  tetracycline
Term
Which microscope can see internal structures of a cell and needs ultrathin sections so electrons can pass through the specimen?
Definition
Transmission Electron Microscope
Term
What microscope enhances diffraction of the light that passes through a live specimen to see the internal structures of cells with out stain?
Definition
Phase-contrast microscope
Term
What microscope is used to stuy surface features of a specimen?
Definition
Scanning electron Microscope
Term
What microscope uses visible light to see a specimen against a bright background and uses stains to create contrast?
Definition
compound light microscope
Term
What microscope uses UV light, flourescent stains and antibodies to ake a specimen glow, and allows rapid detection of pathogens in tissues?
Definition
Fluorescence microscope
Term
What microscope has a special condenser that blocks most light to see the outline of a live specimen with out staining?
Definition
Darkfield microscope
Term
What is the ability of lenses to distinguish two points?
Definition
refraction
Term

What is the composition and function of the plasma membrane for a prokaryote?

Eucaryote?

Definition

Prokaryote- composition: made of phospholipids and proteins

function: permeability, makes ATP, Transportation

Eukaryote- composition: Phospholipid bilayer, sterols

Funtion: transportation 

Term

What is the comopsition and function of the cell wall of a prokaryote?

eukayote?

 

Definition

Prokaryote- composition: peptidoglycan

Function: protection

 

Eukaryote- no cell walls

Term

What is the funtion and composition of ribosomes in a eukaryote?

prokaryote?

Definition

Both: function: protein synthesis

composition: protein

Term

What is the composition and function of chromosomes in a prokaryote?

eukaryote?

Definition

Prokaryote- composition: nucleic acids (DNA) 1 chromosome 

Function: storage of information

 

Eukaryote- composition: 46 DNA

function: storage of information

 

Term
In what ways do eukaryotes and prokaryotes preform cell division?
Definition

Prokaryotes: binary fission

 

Eukaryotes: meiosis and mitosis

Term

What is the optimum temp for Mesophiles? psychrophiles? psychrotrophs? Thermophiles? hyperthermophiles?

 

Definition

in order:

37 C

13 C

23 C

62 C

93 C

Term
What is the danger zone for bacteria where some may produce toxins?
Definition
15 C - 51 C
Term
What do microbes need to make organic molecules ot form their cell structures? What are these organic molecules?
Definition

Carbon

 

Carbohydrates, proteins, lipids, nucleic acids

Term
What element do microbes need as a source of energy?
Definition
carbon
Term
What element do microbes need to make proteins and nucleic acids besides carbon?
Definition
nitrogen
Term
How do microbes aquire nitrogen?
Definition

protein sources (food)

 

 

Nitrogen fixing bacteria can get nitrogen from the atmosphere

Term
What important role does sulfur play in microbial growth?
Definition
its needed to make some amino acids and vitamins
Term
What element do microbes need to make nucleic acids and the bilayer of plasma membranes.
Definition
phosphorus
Term
What element(s) do microbes need to make cofactors of enzymes?
Definition
trace elements, mineral elements
Term
What are organic growth factors? Give an example of some.
Definition

essential organic compounds from the environment

 

eg. vitamins, amino acids, and bases of DNA and RNA

Term
What pH do bacteria like?
Definition
neutral, 6.5 - 7.5
Term

What pH do fungi like?

 

Definition
acidic 5-6
Term

Nutrients prepared to grow microbes

eg. nutrient agar

Definition
Culture Medium
Term
Contains no living microbes
Definition
sterile
Term
microbe introduced into a culture medium to initate growth
Definition
inoculum
Term
microbes growing in/on a culture medium
Definition
culture
Term
contains only one species or strain
Definition
pure culture
Term
a visible mass of microbial cells that arose from a single cell, spore, or a group of attached cells
Definition
colony
Term

what does preserbing bacterial cultures for a long term do to bacteria? How long does this last?

 

Definition

totaly stops metabolism

 

years

Term
What does preserving bacterial cultures for a short term do to bacteria? How long does this last?
Definition

slows down metabolism

 

3-4 months

Term
name and define 2 long term ways to preserve bacterial cultures and the temperature they are stored at
Definition

Deep-freezing - in liquid nitrogen -50 to -95 C

 

Lyophilization- freeze drying; dehydrate in a vacuume then freeze  -54 to -72 C

Term
Name 2 methods of obtaining a pure culture
Definition

pour plate method

streak plate method

Term

Which culture media has a chemical composition that varies slightly per batch and is routinely used to grow many kinds of bacteria?

eg. nutrient agar

Definition
Complex media
Term
which culture media are we using where the exact chemical composition is known?
Definition
chemically defined media
Term

Which culture media suppresses the growth of uneanted microbes and encourages he growth of the desired microbe?

eg. Sabourand agar

Definition
selective media
Term
Which culture media makes it easier to distinguish colonies of desired microbes?
Definition
differential media
Term
which culture media encourages the growth of the desired microbe?
Definition
enrichment media
Term
What is the time for a cell to divide and its population to double called?
Definition
generation time
Term
Which phase of the bacterial growth curve is intense cellular activity and no cell division?
Definition
lag phase
Term
Which phase of the bacterial growth curve used to determine generation time, is most effective to treat infections, and is under optimum conditions?
Definition
log phase
Term
Which phase of the bacterial growth curve is slower growth and has new cells and dying cells?
Definition
stationary phase
Term
which phase of the bacterial growth curve shows a logarithmic decline where dying cells exceed new cells formed?
Definition
Death phase
Term
Name the 4 phases of the bacterial growth curve.
Definition

lag phase

log phase

stationary phase

death phase

Term
Name the 4 direct methods of measuring microbial growth.
Definition

plate count

most probable number (mpn)

direct microscope count

filtration

Term
Which method of measuring microbial growth is a common method for estimating the number of bacteria in a sample, uses colony forming units (CFU), and assumes that each bacterial cell grows in a single colony?
Definition
Plate count
Term
What are the advantages and disadvantages of a plate count in measuring microbial growth?
Definition

A: counts only the number of living viable cells

 

D: -need a lot of materials to preform serial dilutions of a sample

-requires time for incubation

Term
Which method of measuring microbial growth is a statistical estimation of a bacterial count and is used when microbes wont grow on solid media or will only grow in liquid differential media.
Definition
Most Probale Number (MPN)
Term
which method in measuring microbial growth uses a special slide that can hold a measured volume of bacterial suspension?
Definition
direct microscope count
Term
What are the advantages and disadvantages of the direct microscope count method in measuring microbial growth?
Definition

A: a fast way of counting the number of cells

D: -requires a high concenration of cells in a sample

-does not work if the baceria are motile

-counts living and dead cells

Term
which method in measuring microbial gowth is where bacteria are sieved out onto the surface of a membrane filter then transferred to a culture medium and the CFUs are counted?
Definition
Filtration method
Term
Which method in measuring microbial growth is a useful method when the bacterial count is low?
Definition
Filtration method
Term
Name the 3 indirect methods of measuring microbial growth.
Definition

turbidity

metabolic activity

dry weight

Term
Which method for measuring microbial growth measures the level of cloudiness and uses an instrument that measures he amount of light that passes through a suspension of cells? What is that instrument called?
Definition

Turbidity

 

spectrophotometer

Term
Which method in measuring microbial growth measures he amount of metaolic profucts such as acid, gas, and enzyme production?
Definition
Metabolic Activity method
Term
Which method in measuring microbial growth is used for filamentous organisms, like fungi and algae, that can be grown, dried, and weighed?
Definition
Dry weight method
Term
What is the structure in a bacteria that is small, circular, self replicating DNA that may contain a few genes?
Definition
plasmid
Term
What type of media is a Mannitol salt agar?
Definition
selective and differential
Term
what type of medium is a blood agar?
Definition
differential
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