Week 1 + 2

Question 1

miasma theory

Answer 1

diseases thought to be caused by “bad air”

Question 2

bubonic plague

Answer 2

-caused by bacterium yersmia pestis
-spread by fleas, rodents, caused infection in lymph nodes

Question 3

smallpox

Answer 3

-caused by variola virus
-caused skin lesions
-airborne

Question 4

cholera

Answer 4

-caused by bacterium vibrio cholerae
-caused infection of SI
-transmitted through contaminated food/water

Question 5

Robert Hooke

Answer 5

-built first compound lens microscope
-first to see eukaryotic microbes

Question 6

Antonie Van Leeuwehoek

Answer 6

-experimented magnifying lens
-first to observe single-celled organisms

Question 7

germ theory + contributors

Answer 7

diseases caused by microorganisms

Florence Nightingale:
-founder of medical stats, found soldiers died of infections more than battle wounds, showed statistical correlation w sanitation and mortality

Louis Pasteur:
-discovered microbial fermentation produces lactic acid or alcohol
-disproved spontaneity theory using swan flask
-developed 1st artificial vaccine

Joseph Lister:
-surgeon who enforced sterilization during surgery

Question 8

Robert Koch

Answer 8

founder of scientific method of microbio, developed kock’s postulates

1. microbe found in all cases of diseases
2. microbe isolated, grown in pure culture
3. injected into healthy host, same disease occurs
4. same strain retrieved from new host

Question 9

Edward Jenner

Answer 9

-found exposure to cowpox produces immunity to severe smallpox, developed vaccine

Question 10

Carl Woese

Answer 10

-studied bacteria that ahve adapted to life in extreme environental conditions
-Analysis of 16S ribosomal RNA (rRNA) gene
sequences revealed that these prokaryotes
were a distinct life form
◦ Woese coined the name Archaea

Question 11

viruses

Answer 11

-non-cellular particle containing genetic material that takes over metabolism of cell to create new particles
-discovered by Dmitri Ivanovsky

Question 12

Alexander Fleming

Answer 12

discovery of antibiotics
-isolated for penicillin, found it stops growth of staphylcoccus bacteria
-pfizer manufactured penicillin

Question 13

human health and concerns

Answer 13

optimism with eradicating diseases with vaccines

concerns:
-population density
-climate change (fungal diseases grow more in warm weather and spreads faster)
-emergence of old and new diseases

Question 14

antimicrobial drug resistance (ADR)

Answer 14

increased antibiotic use leads to drug resistance
-healthcare cost increases

Question 15

what is fermentation

Answer 15

absence of oxygen, carbon source consumed by microbe to gain energy and grow larger

Question 16

explain prokaryotes

Answer 16

-no nucleus
-includes bacteria and archaea
-divides through binary fission
-cell walls
-phototrophic and heterotrophic
-includes fungi, mammals, protists

Question 17

explain eukaryotes

Answer 17

-has membrane-bound nucleus
-divides through mitosis or meiosis
-includes algae and plats, fungi and animals
-cell walls

Question 18

endosymbiont theory

Answer 18

-first forms of life were prokaryotes
-large prokaryote cell engulfed smaller bacteria
-bacteria provided energy, helped each other, became permanent parts of the larger cell
-led to the development of complex cells branching off into eukaryotic cells
-idea that eukaryotes evolved from prokaryotes

Question 19

how is a species defined?

Answer 19

-high degree of genomic relatedness based on housekeeping genes, very central function within cell
-share common traits (habitat, ell shape, nutrient requirements)

Question 20

explain bacteria

Answer 20

-found in nearly every habitat
-mostly harmless or beneficial, small number of pathogens
-cell walls: peptidoglycan (amino acids + sugars)
-photosynthetic or non-photosynthetic
-huge metabolic diversity
-diverse shapes
coccus, bacillus, vibrio, coccobacillus, spirillum, spirochete

Question 21

explain archaea

Answer 21

-found in nearly every habitat
-extremophiles
-no known human pathogens
-cells with pseudopeptidoglycan

Question 22

what do eukaryotes includes

Answer 22

protists,:

algae: uni or multi-cellular, photosynthetic, have cellulose cell walls
protozoa: diverse, photosynthetic, parasitic, or pathogenic

fungi:

Yeasts: unicellular
molds/filamentous fungi: multicellular, made of long filaments forming visible colonies, connects to roots of plants nd trees, critical to decomposition and nutrient cycling

Question 23

what does magnification require?

Answer 23

resolution: ability to distinguish between 2 separate points, low resolutions is fuzzy, high is sharp, is affected by wavelength and numerical aperture (NA) must be high

contrast: difficult to distinguish small structures in microorganisms due to transparency

Question 24

what are the kinds of light microscopy?

Answer 24

bright field
dark field
phase contrast
fluorescence
electron microscopy

Question 25

how do optics and properties of light affect ability to view objects?

Answer 25

as wavelength lengthens, gets weaker, less frequency, limits size of the object that can be seen

Question 26

describe how an oil immmersion lens works

Answer 26

-put drop of oil between lens and object to minimize loss of refracted light at widest angles, sharpens the image

Question 27

explain bright field microscopy

Answer 27

-object appears as dark silhouette -limit of resolution is 1000x -observe microbes by placing in drop of water on glass slide with coverslip (wet mount) -can see cells in natural state, detection and resolution enhanced by staining

Question 28

gram staining

Answer 28

-Use same procedure to differentiate -Differential stain, differentiates between 2 types of bacteria -Gram positive: retain crystal violet stain because of thicker cell wall, cells appear purple colour -Gram-negative: bacteria do not retain stain, cells appear pink/reddish colour

Question 29

acid-fast staining

Answer 29

Differentiates two types of gram-positive cells: those with waxy mycolic acids in cell walls vs those without

Question 30

capsule staining

Answer 30

-Certain bacteria and yeasts have protective outer structure called a capsule -presence of capsule relates to microbe's virulence, and the ability weather cells have them is an important diagnostic took -Negative staining technique required (India ink stains surrounding medium, not capsule)

Question 31

endospore staining

Answer 31

-Produced within certain bacterial cells to survive harsh conditions -Ex: bacillus species form highly resistant endospores, highly resistant to normal stain (gram stain)

Question 32

phase contrast microscopy

Answer 32

-exploits differences in refractive index between cytoplasm and surrounding medium, or different organelles -Contrast between cells and background increased -Used to view live unfixed cells and cellular organelles -Can see how a specific microbes structure generally looks like without staining

Question 33

Fluorescence microscopy

Answer 33

-Detects "parts" of cells -specimen absorbs light then emits lights of lower energy, specimen fluoresces -Autofluorescence: some cell components naturally fluoresce under specific light wavelengths -Fluorophores: fluorescent compounds or proteins that CAN fluorescent

Question 34

describe the immunofluorescence technique

Answer 34

technique used to identify certain disease-causing microbes by observing whether antibodies bind to them 1. Antigen is fixed to surface 2. Patient serum added, antibodies (if present) bind to antigen 3. Secondary antibody (fluorescent) is added, binds to patient antibodies if present

Question 35

Electron Microscope (EM) and two types

Answer 35

beams of electrons instead of light in visible spectrum, has higher energy and shorter wavelengths, improves resolution power to see smaller objects Scanning electron microscope (SEM): creates image by detecting reflected electrons, see 3D structure of organism and surface Transmission Electron Microscope (TEM): electrons pass through thin sections of sample to create an image, the electron-dense regions appear darker, looks 2D, one plane, see inside and the surface