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Microbiology > Lecture 1 Objectives > Flashcards

Lecture 1 Objectives Flashcards

1
Q

What is abiogenesis (spontaneous generation) ?

A

living organisms arise from nonliving matter, a vital force forms life

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2
Q

What is biogenesis?

A

living organism arise from preexisting life

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3
Q

Describes Louis Pasteur’s swan-necked flask experiment and explain what it proves?

A

Conditions: Nutrient broth placed in flask, heated, not sealed - flask remains upright
Results: No microbial growth
Conditions: Nutrient broth placed in flask, heated, not sealed- flask tilted
Results: Microbial growth
Proves: Biogenesis
microorganisms are present in the air

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4
Q

Give 5 ways in which microorganisms benefit humankind?

A
  1. Fermentation
  2. recycle carbon, nutrients, sulfur, and phosphorus that can be used by plants and animals
  3. Microbial ecology, degrade organic matter in sewage and degrade or detoxify pollutants such as oils and mercury
  4. to prevent surgical wound infections
  5. Vaccinations
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5
Q

Give 2 ways in which microorganisms harm humankind?

A
  1. infectious disease

2. pathogen overcomes the hosts resistance

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6
Q

Describe 3 Pasteur’s accomplishments?

A
  1. microbes are responsible for fermentation
  2. fermentation is the conversion of sugar to alcohol to make beer and wine
  3. microbial growth is also responsible for spoilage of food
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7
Q

Define Magnification.

A

Objective lens x ocular lens

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8
Q

Define Resolution.

A

the ability of the lenses to distinguish two points

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9
Q

Define Refractive index.

A

Th light-bending ability of a medium

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10
Q

What effect does the wavelength of light have on microscopic resolution?

A

Shorter wavelengths of light gives greater resolution.

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11
Q

What is a brightfield illumination?

A
  • Dark objects are visible against a bright background

- light reflected off the specimen DOESN’T enter the objective lens

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12
Q

What is darkfield illumination?

A
  • light objects are visible against a dark

- light reflected off the specimen DOES enter the objective lens

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13
Q

What is phase-contrast microscopy?

A

Accentuates DIFFRACTION of the light that passes through a specimen

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14
Q

What is fluorescence microscopy?

A
  • uses UV light
  • fluorescent substances absorb uv light and emit visible light
  • cells may be stained with fluorescent dyes (fluorochromes)
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15
Q

What is Transmission Electron Microscopy?

A
  • uses electrons, ultra thin sections of specimens
  • light passes through specimen, then an electromagnetic lens to a screen or film
  • specimens may be stained with HEAVY METALS
  • 10,000-100,000
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16
Q

What is Scanning Electron Microscopy?

A
  • 3D images
  • electron GUN produces a beam of electrons that scabs the surface of a whole specimen
  • SECONDARY electrons emitted from the specimen produce the image
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17
Q

What is Simple Staining ?

A

Uses a single basic dye

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18
Q

What are two types differential staining?

A
  1. Gram staining

2. Acid-fast staining

19
Q

What is gram staining?

A
  • gram stains classifies bacteria into gram-positive or gram-negative
  • (+) killed by penicillin and detergents
  • (-) killed by antibiotics
20
Q

What is acid-fast staining?

A
  • cells that retain a basic stain in the presence of acid-alcohol
  • non-acid-fast cells lose color
  • (+) holds on to stain
  • (-) doesn’t hold on to stain
21
Q

What is special staining?

A
  • negative staining is useful for CAPSULES
  • HEAT (or time) is required to drive a stain into ENDOSPORES
  • FLAGELLA staining requires a MORDANT to make the flagella wide enough to see
22
Q

Describe two reasons why gram staining an unknown bacterium would be important.

A

To find out:

  1. Shape
  2. Arrangement
23
Q

What are 3 most common morphologies of bacteria?

A
  1. coci- 2um
  2. rod- 2um
  3. spiral- 5um
24
Q

What are some other possible shapes?

A
  1. star-shaped stella

2. square halaoarcula

25
Q

Explain the cell walls of gram+ bacteria

A
  • THICK peptidoglycan
  • has teichoic acid= lipoteichoic acid links to plasma membrane and wall teichoic acid links to peptidoglycan
  • in acid-fast cells, contains MYCOLIC acid
  • regulate movement of cations
  • polysaccharides provide antigenic variation
26
Q

Explain cell walls of gram- bacteria

A
  • THIN peptidoglycan
  • NO teichoic acids
  • outer membrane
  • have 2 lipid membranes
  • LIPOpolysaccharides, LIPOproteins, phosphoLIPIDS (focus on fat)
  • forms PERIPLASM between the outer membrane and the plasma membrane
  • protection from phagocytes, complemement and antibiotics
  • O polysaccharide antigen (E.Coli O157H7)
  • Lipid A is an endotoxin (toxic)
  • Porins (proteins) form channels through membrane
27
Q

What is the structure and function of a Bacterial Capsule?

A
  • under glycocalyx
  • neatly organized
  • capsules PREVENT phagocytosis
28
Q

What is the structure and function of a Slime Layer?

A
  • under glycolayx
  • unorganized and loose
  • extracellular polysaccharide allows cells to attach
29
Q

What is the structure and function of a Pili?

A
  • under axial filaments

- used to transfer DNA from one cell to another

30
Q

What is the structure and function of a Fimbriae?

A
  • under axial filaments

- allow attachment

31
Q

List the 4 arrangements of flagella in bacteria.

A
  1. Monotrichous
  2. Lophotrichous
  3. Amphitrichous
  4. Peritrichous
32
Q

What is Monotrichous?

A

flagella on a single end

33
Q

What is Lophotrichous?

A

flagella on either one or both ends

34
Q

What is Amphitrichous?

A

flagella on each end

35
Q

What is Pertrichous?

A

flagella all around the cell

36
Q

What are characteristics of prokaryotes?

A
  • ONE circular chromosome, not in a membrane
  • NO histones
  • NO membrane-bound organelles
  • has peptidoglycan walls
  • BINARY FISSION (divide into two)
37
Q

What are characteristics of eukaryotes?

A
  • PAIRED chromosomes, in nuclear membrane
  • HAS histones (wrap DNA)
  • organelles
  • Polysaccharide cell walls
  • Mitotic spindle
38
Q

What are Protoplasts?

A

has COMPLETELY lost its cell wall

39
Q

What are Spheroplasts?

A

has ALMOST completely lost its cell wall

40
Q

What are L-forms?

A

WALL-LESS cells that swell intro irregular shapes

41
Q

What are two cell damaged walls that ARE susceptible to osmotic lysis?

A
  1. Protoplast

2. Spheroplast

42
Q

What are the effects of Lysozyme in bacterial cell walls.

A

DIGESTS disaccharide in Peptidoglycan

43
Q

What are the effects of Penicillin in bacterial cell walls?

A

INHIBITS peptide bridges in Peptidoglycan

Microbiology (11 decks)

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