UNIT 1 Exam Flashcards
(101 cards)
1
Q
What is microbiology?
A
The study of microscopic life
2
Q
Who is the father of microbiology, and when did he discover it?
A
Antonie Van Leeuwenhoek in 1676
3
Q
The first name of bacteria and protist from Antonie
A
Animalcules
4
Q
What are some microbes that aren’t microscopic?
A
-Fungi
-mushrooms
-mold
-giant bacteria
5
Q
What are microscopic animals that aren’t microbes?
A
-tardigrades( they are small but are considered of animals)
6
Q
Groups of microbes
A
-bacteria
-viruses
-fungi
-archaea
-protist (algae and protozoa )
7
Q
Are Archaea capable of pathogenic?
A
No as of now
8
Q
Which microbes are considered cellular?
A
bacteria
archaea
protist
fungi
9
Q
Which microbes are considered acelluar
A
virus
10
Q
Which microbes are considered prokaryotes
A
bacteria and archaea
11
Q
Which microbes are considered eukaryotes
A
protist and fugi
12
Q
Does the gross structure feature indicate evidence of evolutionary history or relatedness?
A
No
13
Q
Three domains of life?
A
eukarya
archaea
bacteria
14
Q
How are all living organisms related?
A
Using genes that express ribosomes, as all living things have ribosomes
*hint: This is why viruses aren’t considered life.
15
Q
What are not microbes but are studied in microbiology?
A
-parasitic invertebrates ( animals)
16
Q
What is a parasitic invertebrates?
A
infectious agents transmitted like disease-causing microbes
ex. worms, lice, bedbugs, mosquitoes
17
Q
Name a few benefits of microbes in human life.
A
protection
vitamins
digestion of food
immune system development
antibiotics
medications
oxygen we breathe
decomposers
food
biofuels
18
Q
Microbes are essential for life as we know them
and are the processes that support life. What are some of these?
A
-Biogeochemical cycles
-oxygen production ( over 50% due to algae photosynthesis in the ocean)
-decomposers
19
Q
Microorganisms provide essential models that give
us fundamental knowledge about life processes. Give some examples.
A
- Bacteria, viruses, yeasts.
- Molecular biology: DNA replication, transcription, translation,
protein structure, etc. - Evolution
- Metabolism
- Synthetic Biology
- Cell Biology: structure, cell cycle, etc.
- Genetics
- Vaccine development
20
Q
Humans utilize and harness microorganisms and their products. Name some.
A
-Fermentation
-Medication ( antibiotics or cancer drugs from fungi)
-bioregeneration
-green fuel
21
Q
When was it figured out that microbes may cause disease? What is this theory known as?
A
18th-century, Germ theory
22
Q
Who developed the methods to identify if microbes can cause disease?
A
Robert Koch
- they use the methods known as Koch postulates
( usually applies to new diseases)
23
Q
Give all the steps of the Koch Postulates
A
- The disease agent must be present
in each case of the disease and
absent in the healthy.
2.The agent must be isolated in a
pure culture from the lesions of the
disease.
3.The agent must cause the same
disease when inoculated in a
healthy and susceptible animals.
4.The same agent must be isolated
in the lesions of the new animals.
24
Q
What are the limitations of Koch’s Postulates?
A
-some microbes do not present symptoms in all infected host
-some microbes cannot be grown in pure culture
-it is not ethical to do studies on humans
-some animal models may not translate to humans
ex. HIV( only happens in humans)
25
Microbes shape human history. Name some fundamental historical points of microbes.
* 10,000 BCE Fermentation and Disease
* 1300-1400 CE Bubonic Plague
* 1676 Microbes are observed under a microscope
* 18th century – Germ theory of disease
* 1845- 1849 Irish potato famine
* Golden age of microbiology (late 1800s)
-Sanitation, antisepsis, and vaccines
- Reduce mortality
26
List and describe three elements of good microscopy.
-magnification
-resolution-detail
-contrast- color/brightness
27
Identify the different forms of light microscopy.
bright field
dark field
phase contrast
interference (DIC)
-UV-light microscopes (fluorescence)
-laser-"light" microscopes (confocal)
28
Identify the different forms of electron microscopy.
Scanning Electron Microscopy
Transmission Electron Microscopy
29
Identify and describe the shapes and arrangements of bacteria.
Bacilli- Rod-shaped
Cocci- spherical
spirilla- spiral shaped
30
How does the binomial system function?
-Genus species
names are italicized to signify a model organism that can be grown
the genus is always capitalized, but not the species name
The genus can be shared, so it can be abbreviated by one letter.
ex. Staphylococcus aureus ( S. aureus)
31
Which type of cellular organism is the most diverse?
prokaryotes are the most diverse and numerous on earth
32
Bright Field Microscopy
-Samples are fixed and stained
2D images with high contrast and colorful
-Wet mounts
3D ish, low contrast, no color, and may be able to see movement
33
Dark Field Microscopy
-live specimens, no stains
-dark background, light specimen
34
Phase Contrast Microscopy
-living samples
-no stains
-3D
-more contrast
35
Fluorescence( UV Light)
-Fixed and stained samples
Fluorescent dyes
-Can see large quantities of molecules
-computer assistance
36
Confocal Microscopy
-Fixed and stained
fluorescent stains
-takes images in planes
-computer stacks the planes to generate a 3D image
37
Electron Microscopy
-Uses a beam of electrons rather than light
-100x better resolution
-magnification up to 100,000x
-used to visualize viruses
38
Transmission electron microscopy TEM
-electrons are transmitted through the specimen
-thinly cut samples
-heavy metal stains
-2D
39
Scanning Electron microscopy SEM
-electrons pass over the surface of the sample
-3D samples
-Heavy metal stains
-3D images
40
How to read magnifying power?
-Total magnification(TM) is reported
magnification of ocular x objective= TM
ex.
10x10
40x10
200x10
side note: bacteria are visible at 1000 TM
Our lab microscopes always have a 10x ocular lens
41
What purpose does oil serve in microscopes?
When using 100x magnification, it refracts light to retain resolution.
42
Bacteria cell arrangements for coccus
Staphylococci-clustered cocci
diplococci- two cocci
streptococci- linear cocci
43
bacteria cell arrangements for bacillus
diplobacilli
streptobacilli
44
Describe secreted molecules
Enzymes
toxins
siderophores
45
enzyme function
* “Digest” food
* Hemolysin
* Protease
* Lipase
| Hemolysin is a enzyme that breaks down blood.
46
toxins function
* Neurotoxins
* Damage to the immune system
47
siderophores function
* Low-weight molecules
* High affinity to iron
used for growth and replication
48
Name the 3 appendages and their function.
* Fimbriae
* Flagellum – 1-10s per cell
* Pili
* Function in protection,
attachment, horizontal gene
transfer, motility,
pathogenesis
49
Fimbriae
* Small, bristle-like fibers
sprouting off the surface of
certain species of bacteria
Proteins
* Attachment
act like velcro
| an adhesens group that reffers to sturctures that allow for attachment.
50
Pilus
* Long, rigid, tubular structure made
of proteins, 1-10 per cell
* Function
Attachment
Conjugation
Twitching motility( attachment and crawling with that attachment)
| Conjugation is the passage of DNA to another cell
## Footnote
For the purposes of this couse we dont consider conjugation a virulance factor
51
Flagella
* 1-10s per cell
* Made out of proteins
* Function
Attachment
Motility/swimming
Moves 360°
| is a left handed helix
## Footnote
Counterclockwise - forward swimming
clockwise -backward swimming
52
Explain how flagellar motility and -taxis enable bacteria to respond to
environmental change.
* Sensors/receptors in the cell tell the flagella
where to go
- Chemo – attractants/repellants
- Photo - light
- Aero - oxygen conc.
53
Describe the structure and function of the glycocalyx.
* Exopolysaccharide
* Outermost layer in the cell envelope
* Types of structure: Capsules and slime layers
* Aid in attachment
* Provide protection
Host immune system
Desiccation
Exclude viruses and detergents
| Desiccation: removal of moisture
54
Identify which structures may serve as virulence factors and/or target
for antibiotics.
-Surface-layers (S-layers)
-glycocalyx
55
Surface Layers (S-layers)
* Proteins in a single layer
* Chain-mail-like armor
* Protection from antibiotics and host
immune system
* Attachment
56
how is Lymes disease an example of bacterial mobility?
* Bull’s eye rash
* Borrelia burgdorferi
* Tick bite
* Bacteria replicate and spread away
from the bite at speeds of ~1-4 μm per
second, or a little over half of an inch
per hour at maximum speeds
57
Virulence Factors
Replicate
Attach
Spread
Escape immune system
Cause damage
## Footnote
Pathogen vs Virulence
* Virulence: how severe is the disease?
* More virulence factors, more virulent pathogen*
* Fewer virulence factors, less virulent pathogen*
*Host health can also affect virulence
58
Name the biochemical composition of bacterial cells.
-External : Appendages and Surface Layers
-Envelope
-Internal
-Secretion
59
What are the types of surface layers
-glycocalyx
-s-layers
60
Bacterial cell envelope componets?
(outer membrane)
cell wall
cytoplasmic membrane
| () only some bacteria have it
## Footnote
cytoplasmic membrane also know as the cell membrane or PM
61
Function of Cell Membrane
* Selectively permeable barrier ( composed of lipids and proteins)
* Interacts with the external
environment
Receptors
Transport proteins
* Energy reactions
Electron transport chain
| EUK: the ETC happens in Mitochondria compared to cells it found in CM
62
Chemical Strucuture of Bacterial Cell membrane
-Sterols affect the fluidity of the
membrane
Animals use - cholesterol.
In bacteria hopanoids, or hopanes.
63
Cell wall Arragments
Gram-Positive
Gram-Negative
64
Composition of Bacteria Cell wall?
* Peptidoglycan (murein)
two alternating sugars
* N-acetylglucosamine (NAG)
* N- acetylmuramic acid (NAM)
alternating D- and L- amino acids
| From NAM 5 amino acids will be bound , never to NAG
## Footnote
Bacteria are unique for using D amino acids as builidng blocks
65
Function of Peptidogylcan muerein?
* Helps protect cell from osmotic lysis
* Helps protect from toxic materials
* May contribute to pathogenicity
| All bacteria have peptidogylcan
66
Importance of cell wall: Osmotic Pressure
Any cell with a cell wall provides protection found isotonic and hypotonic enviorment,
additionally it wont help in hypertonic situations
67
What is the strucutre of peptidogylcan?
Mesh like polymer of identical subunits forming long strands
the bonds formed
-cross links between tetra petide chains
-glycosidic bond between NAM and NAG
| Penicillin breaks down cross links tetra peptide chains.
## Footnote
Lysozymes breaks down glycosidic bonds
68
Gram positive
* THICK peptidoglycan
* 15-80 nm
* Teichoic acids
Arranged with Peptidoglycan and then plasma membrane
| Its belived teichoic acid provides stabilty to peptidogylcan layer
69
Gram Negative
* THIN peptidoglycan 2 nm
* Outer membrane
Lipopolysaccharides, proteins , porins ,Polymyxins
Order goes outermembrane followed by thin peptidogylcan layer and then cytoplamsic membrane
| Due to its 3 layers makes them more resitant to killing. More Virulent
70
What is the role of lipopolysaccharide LPS in bacterial cell walls?
* Lipid A - endotoxin
* O polysaccharide – evade immune system
71
nontypical cell walls
* Some bacteria do not have a cell wall
* Some have an alternate arrangement
Mycobacterium
Can cause tuberculosis and leprosy
* Mycolic acids ( acid fast cell walls)
Very-long-chain fatty acid
72
What color does each type of bacterial wall stain?
Positive-Purple
Negative-Pink
Mycobacteria- Do not Stain
73
Rank order of how easy is to kill bacteria based on cell wall?( 1 easy and 3 hardest)
1.positive
2.negative
3.Mycobacterium
74
What are the structures that exist with in bacterial cells?
Cytoplasm
Ribosomes
inclusions
nucleoid/chromosomes
cytoskeleton
endospore
plasmid
microcomparments
75
Cytoplasm of bacterial cells
* Largest compartment
* Aqueous gel with ions and
small molecules
* Site of ALL reactions
-Metabolism
-Biosynthesis
-Central Dogma
76
Ribosomes of bacterial cells
* rRNA and proteins
* Bacterial and Archaeal
ribosomes: 70S
* Eukaryotic ribosomes: 80S
* Great target for antibiotics!
| the 70s is based on svenberg units
77
Svenberg unit
Sucrose-Gradient technique for determination of sedimentation coeffecients(S)
78
What is the orginization of DNA in bacteria cells?
Chromosome Shape: Circular
Chromosome Number: 1-2
Chromosome Size: small
Plasmid : many
79
DNA strcuture of Eukaryotic Cells
Chromosome Shape: linear
Chromosome number: many
Chromosomes size: large
Plasmids: rare
80
Chromosomes of Bacteria Cells
* 1-2
* Genes necessary for survival
* Circular
* Nucleoid
81
What is a plasmid
* Small circular DNA
* 1-100s
* Non-essential genes
* Horizontal gene transfer (Conjugation)
82
What is the Function of the cytoskeleton in bacterial cells?
* Filamentous proteins, found
under cell membrane and
cytoplasm
* Give bacterial cells shape
* Also involved in cell division
FtsZ
83
What are the major cytoskeleton shapes of bacteria?
FtsZ: round Shape
MreB: Rod Shape
CreS: Curved shape
84
What are some speacilized structures of bacterila cells?
-Intracelluar membrane folds
-Inclusions
-Microcompartments
| not involded in virulance
85
Intracellular Membrane Folds
Cell membrane folds
* photosynthetic bacteria
* bacteria with high respiratory activity
86
Inclusions
* Storage granules
Storage of nutrients, metabolic end
products, energy, building blocks
* Gas vesicles
Protein-bound gas-filled structures that
increase buoyancy
| composed of proteins not a membrane.
## Footnote
they can store complex carbohydrates
87
Microcomparments
* Protein shells
* Carboxysomes: packed with the
enzyme protein shells Rubisco for CO2
fixation
| conversion of CO2 into carbohydrates.
88
What is an endospore?
* Internal structures of some
bacteria
Gram positive
* Facilitates survival by
withstanding hostile conditions.
* Heat, Drying, Freezing, Radiation,
Chemicals, Low nutrients
| We consider a virulent factor, it is dormant
89
What is the process of sporulation?
Two Phase cycle
- vegetative cell encounters harmful enviorment
- the cell will create an endospore to hold important properties and can survive forever.
- if the dangerous enviroment is evaded it will revert to a replicative cell
90
What is the significance of sporulaiton?
The problem:
* Resistant to boiling, soaps,
disinfectants, UV light, and
antibiotics
* Big problem in home canning.
Diseases related to endospores
* Bacillus anthracis: Anthrax
* Clostridium tetani: Tetanus
(lockjaw)
* C. perfringens: gas gangrene
* C. botulinum: botulism
91
Identify antibiotic targets within the bacteria cell.
Cell wall
DNA synthesis
RNA synthesis
outer membrane ( gram negative)
ribosomes
metabolic pathways
92
Describe the Typical Archeal Cell
Ancient prokaryotes that are found in extreme environments.
* Extreme environments
* Hyperthermophiles ( over 60 C )
* Psychrophiles ( below 15 C)
* Acidophiles/Alkaliphiles ( enjoy low pH or high pH)
* Halophiles ( enjoy high salt content)
* Deep sea - barophiles
* Discovered in 1977
* Prokaryote
* Found in all environments,
including our bodies
* Found in beneficial associations
with bacteria, plants, and animals
* None are pathogenic
93
Archael Cell shapes
* Cocci and rods
* Other shapes can also exist.
Branched/flat shapes
94
Archael Appendages
Unique
* Cannulae - attachment
* Hami – horizontal gene transfer,
attachment, motility
Similar
* Flagella – archaella
| Hami function wise similar to pilli but structure wise different
95
Archael Cell Envelopes
* Differ from bacterial envelopes in the molecular makeup and
organization.
* Very diverse arrangements, but:
-Lack peptidoglycan
-Glycocalyx rare
-S-layers very common
96
Plasma Membrane Fluidity of archael cells
* Length of fatty acid
* Saturation level of fatty acid
* Steroid content
* Temperature
97
Composition of Archeal Membranes
| Talking about archeal that live in extreme heats
* Composed of unique lipids
-Isoprene units (five carbon,
branched)
-Ether linkages rather than ester
linkages to glycerol.
* Some have a monolayer structure
instead of a bilayer structure.
| allows for maintaing the proper fluidity in hot temaptures.
## Footnote
monolayers is long chain of fatty acid with phospholipid heads
98
Internal Strucutures of Archael Cells
* All the usual components
-Ribosomes (70s)
-Inclusion bodies
-Few circular chromosomes
-Plasmids
* Histone-like proteins
* Important in regulation of
gene expression
* Unique metabolisms
Methanogenesis
99
Methanogens from gut to globe by archeal cells
* Produce methane
* Strict anaerobes
* Grow in soil, in animal digestive
tracts, in marine floor sediment, and
in wetlands.
| Humans fart methane and cows burp them
100
Haloarachaea
* High-salt environments at least 1.5-M
NaCl.
* Most are phototrophs.
* Bacteriorhodopsin/Archaeorhodopsin
* Gas vesicles (GV)
| They will reside in the top when there is sunlight via their GV
## Footnote
Bacteriorhodopsin have a pump that activated by light which allows the formation of ATP
101
Human gut and interactions with bacteria and methanogens
Bacteria break down polysacharides with byproducts of short chain fatty acids and H2,
1. H2 buildup from bacterial fermentation normally feeback-inhibits fermentaion. If that feedback loop is lost we will continue to produce short chain fatty acid.
2. H2 oxidation by methnognes if present counteracts H2 build up allowing fermentation to continue
3. fermentation end products such as acetate and butyrate are readity utilized by human cell resulting in weight gain
| all this is hypothesis
