MIBO exam 1 Flashcards


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1

Robert Hooke

Built the first compound microscope

Published Micrographia

Coined the term “cell”

2

Leeuwenhoek

Built single-lens magnifier which was stronger than Hooke's so first to observe single-celled microbes and note movement in microbes

Called them "small animals"

3

Spontaneous generation

Living matter can be generated from non-living matter

4

Redi, Spallanzani, Pasteur

Disproved spontaneous generation

5

Redi

Disproved spontaneous generation by observing flies/maggots on meat covered and uncovered

6

Spallanzani

Disproved spontaneous generation via broth in flask sealed/unsealed

7

Pasteur

Disproved spontaneous generation via swan neck flask

8

Germ Theory

Theory that many diseases are caused by microbes

9

Chain of infection

Transmission of disease

10

Pure culture

Culture from a single parent cell- only 1 type of organism

11

Colony

Distinct populations grown from a single-cell... pure cultures grown on semi-solid surface, not used for liquid-grown cultures

All colonies are pure cultures, but not all pure cultures are colonies

12

Koch

First guidelines to establish a link between specific microbe and disease

13

Koch's postulates

1. Microorganism must be present in every case of the disease AND absent from healthy organisms

2. Microorganisms must be isolated from diseased organism and grown in pure culture

3. When microorganism inoculated in health host, same disease must result

4. Same microorganism must be isolated from 2nd diseased host

14

Barry Marshall

Found the cause of stomach ulcers (Helicobacter pylori)

Koch's postulates were difficult to follow to prove it

15

Alexander Fleming

Discoverer of penicillin- kills bacteria

16

Howard Florey and Ernst Chain

Purified pencillin

17

Winogradsky

First to study microbes in their natural habitats

- discovered lithotrophs, made Winogradsky column, developed enrichment cultures

- brought about idea that we may have a symbiotic relationship with microbes

18

Resolution

Ability to distinguish small objects close together- all microscopes have it

19

Magnification

Enlarged image of an object- all microscopes have it

20

Contrast

Difference in color intensity between an object and its background

21

Types of light microscopes

Bright-field

Dark-field

Phase-contrast

Fluorescence

22

Compound microscope

Image formed from 2 or more lenses

23

Ocular lens

Fixed magnifying power (10X)- forms virtual image from real image from objective lens

24

Objective lens

Magnification must be set by user- forms real image

25

Total magnification

Product of magnification of objective lens and ocular lens (10X * objective lens magnification)

26

Condenser

Collects and directs light from the source to the specimen

27

Bright-field

Bad resolution, no contrast, can't see viruses (limit is 2 um)

28

Refraction

Bending of light as it passes through an object that slows its speed

- immersion oil can correct refraction because n(oil) = n(glass)

29

Dark-field microscopy

limit = 0.1 um, inherently high contrast as particles seen as bright light against dark background, sensitive to contaminants, can detect microbe movement

30

Phase-contrast microscopy

Used for intracellular morphology because uses difference in refractive indices for organelles

31

Basic Dyes

Methylene blue (blue)

Crystal violet (purple)

Safranin (red)

32

Acidic Dyes

Eosin (pink)

Nigrosin (purple)

- used often for cellular structures/backgrounds

33

Acid-fast staining is used for...

High lipid content cell walls

34

Endospore staining is used for...

vegetative and dormant spore

35

Gram stain procedure

1. Add methanol

2. Add crystal violet stain

3. Add iodine (binds stain to Gram + cells)

4. Wash with ethanol (removes stain from Gram - cells)

5. Add safranin counterstain (stains Gram - cells pink)

36

Pili

1-2 per cell, involved in DNA transfer via conjugation, long and thick, motility

37

Fimbriae

Up to 1000/cell, evenly distributed, short and thin (like hair), help bacteria attach to surface

38

Capsule (glycocalyx)

Outer layer made of polysaccharides, adherence to surfaces, resistant to phagocytosis (evade immune system)

39

Surface layer (S layer)

Consists of proteins/glycoproteins, contributes to cell shape and protects cell from osmotic stress

40

Flagellum

External helical filament, rotary movement propels the cell, swimming motility

41

Actin tails

Alternative method of bacterial movement produced via actin polymerization; move via tails pushing itself through a host cell

42

Plasma membrane

Gram + have 1 PM

Gram - have 2 PM

43

Hopanoids/hopanes

Limit motion of phospholipid tails and stiffen PM (triterpene, lipid)

44

Plasmids

Circular DNA strands that replicate independently, carry genes for antibiotic resistance

45

Macronutrients

Nutrients needed in large quantities- carbon, nitrogen, oxygen, calcium, hydrogen

46

Micronutrients

Nutrients needed in small quantities- copper, nickel, zinc, cobalt

47

Enriched media

Complex media to which specific blood components are added

48

Selective media

Favor growth of one organism over another (ex. can select for gram + or -)

49

Differential media

Exploit differences between 2 species that grow equally well

50

Rickettsia prowazekii

Agent of typhus fever, endemic in flying squirrels, spread through lice, only grows in eukaryotic cytoplasm

51

Heterotrophs

Rely on other organisms for carbon source, break them down, and reassemble their components to make complex cell constituents

52

Autotrophs

Can reduce CO2 themselves to make complex cell constituents

- Phototrophy, chemotrophy (lithotrophy, organotrophy)

53

Phototrophy

Energy triggered by light- the process by which energy from the sun is captured and converted into chemical energy, in the form of ATP

54

Chemotrophy

The synthesis of an organism's energy by the oxidation of electron-donating molecules in the environment... energy generated via redox reactions

- includes lithotrophs and organotrophs

55

Lithotrophs

Autotrophs whose electrons come from inorganic molecules

56

Organotrophs

Autotrophs whose electrons come from organic molecules

57

Photoheterotrophy

Relies on another carbon source, but the energy to use that carbon comes from light

58

ATP Synthase

Fo component is in the membrane, it is a channel that allows protons to move through it (driven by proton motive force energy)

F1 component in cytoplasm, rotates and generates ATP

59

N2 --> NH4 +

Nitrogen fixation

60

Rhizobium

Nitrogen fixer, symbiotic relationship with legume roots because convert atmospheric nitrogen into a usable form for plants

61

NH4 + --> NO3 -

Nitrification

62

NO3 - --> N2

Denitrification

63

Exponential Growth formula

Nt = No * 2n

(Nt = total # of cells, No = original # of cells, n = # rounds of binary fission)

64

Bacterial Growth Curve steps

1. Lag phase (metabolically active, no increase in # of cells)

2. Log phase (primary metabolites synthesized, exponential growth)

3. Stationary phase (growth rate = death rate)

4. Death phase (exponential, 99% of population dies)

65

Primary metabolites

Nucleic acids, amino acids, simple lipids

66

Secondary metabolites

Antibiotics (come in Stationary phase)

67

Continuous culture

All cells in a population achieve a steady state, which allows detailed study of bacterial physiology- keep them at submaximal growth rates so conditions remain virtually constant

68

Chemostat

Ensures log growth by continuously removing and adding equal amounts of culture media

69

TFM

Tracks biofilm mechanical infection method via fluorescence of cell membrane

70

Quorum sensing

Ability to detect and respond to cell population density by gene regulation, the method by which microcolonies communicate, signaling mechanism

- high [autoinducer] (signal protein) = gene on

71

EPS (exopolysaccharide)

Production of natural polymers including production of DNA, sugars, and proteins- sticky

72

Pseudmonas aeruginosa

Opportunistic pathogen, causes cystic fibrosis by forming biofilms on lung soft tissue

73

MPC and Resveratrol

Molecules that prevent biofilm formation and oxidative stress related to eye disease

74

Cell wall

Sacculus- confers rigidity and shape to cell

Protects cell membrane

75

Peptidoglycan

Disaccharide unit of glycan with attached peptide of 4-6 amino acids; cross-bridge formation between parallel strands

- unique to bacteria

NAG and NAM

76

Transpeptidase

Enzyme that cross-links the amino acids in peptidoglycan

- targeted by penicillin

77

Gram + Bacteria

A lot of layers of peptidoglycan threaded by te ichoic acids

78

Gram - bacteria

Have 2 PM- cell membrane covers cell and outer membrane covers thin layer of peptidoglycan

- lipoproteins, LPS, porins

79

Lipoprotein

Connects Gram - outer membrane to peptidoglycan

80

Lipopolysaccharides (LPS)

In outer membrane of gram - cells, act as endotoxins

81

Porins

In outer membrane of gram - cells, allow passage of nutrients into cell... also site of antibiotic entry

82

Mycobacterium

card image

Bacteria genus that contains a capsule, mycolic acids, peptidoglycan, arabinogalactan and inner membrane

83

Mycolic acids

Fatty acids

84

Arabinogalactan

Polysaccharide that links mycolic acid to peptidoglycan in Mycobacterium

85

Mycoplasma

Genus that lacks cell wall, has 3 cell membranes with sterols (for stability), no peptidoglycan, are important pathogens

- pleomorphic (many shapes)

86

Extremophiles

Bacteria that grow under extreme conditions aka. vary from...

- 1 atm

- 37°C (mesophiles)

- pH 5-8 (neutralophiles)

- 0.9% salt

87

Psychrophiles

Microbes that grow in colder than usual conditions (0-20°C)

- accumulate solutes to depress freezing point

- high (unsaturated) fatty acid level adds to membrane fluidity

- enzyme optimal temperature adapts to lower temp.

- lower concentration of DNA stabilizing proteins

FLAVOBACTERIUM

88

Thermophiles/hyperthermophiles

Microbes that grow in warmer than usual conditions (40-120°C)

- Increased Hydrogen bonds

- less flexible polypeptides

- many DNA binding proteins stabilize DNA

THERMUS AQUATICUS (TAQ DNA POLYMERASE)

89

Barophiles

Microbes that grow under extreme pressure (bottom of ocean)

- makes itself more fluid so doesn't burst

90

Halophiles

Microbes that grow in extreme external solute concentration environments

- use energy from excess sodium concentration to power ion pumps that bring necessary molecules into cell

HALOBACTERIUM

91

Staphylococcus aureus

Halotolerant- if there are salty conditions, they can adapt

92

Aerotolerant anaerobe

Grow equally well with or without O2

- oxygen not toxic, but don't need it

93

Facultative anaerobe

Doesn't require O2 but grows better with it, prefers it

94

Acidophiles vs alkaliphiles

pH 0-5 vs pH 9-11

ex. Sulfolobus = acidophile

95

Sterilization

Killing of all living organisms

96

Disinfection

Killing or removal of pathogens from inanimate objects

97

Antisepsis

Killing or removal of pathogens from the surface of living tissues

98

Sanitation

Reducing the microbial population to safe levels

99

Deinococcus radiodurans

Microbe with greatest ability to survive radiation of any organism due to high DNA and protein repair rates

- accumulates tons of manganese that removes ROS