Exam 3 Flashcards
1
Q
Diseases are caused by transferable spore like (“seeds”) particles that could transmit infection (who?)
A
Fracastoro
2
Q
Father of microbiology that 1st described microbes and invented microscope (who?)
A
Van Leeuwenhoek
3
Q
Hand washing prevents childbirth fever (who?)
A
Semmelweis
4
Q
Developed antiseptic in surgery (who?)
A
Lister
5
Q
Disproved spontaneous generation. Also germ theory
A
Pasteur
6
Q
Awarded Nobel prize for work on TB
A
Koch
7
Q
Koch’s postulates (4)
A
Organism must be: 1 - found in all cases 2 - isolated and maint. in pure culture 3 - capable of reproducing infection 4 - retrieved from inoculated animal and recultured
8
Q
What is unique about prokaryotes?
A
Do not have membrane bound organelles
9
Q
Coccus is what shape
A
Circle/sphere
10
Q
Bacillus are what shap
A
Rod
11
Q
Spirillum are what shape
A
Spiral
12
Q
Coccobacillus are what shape
A
Rod-shaped with round ends
13
Q
Capsule or slime layer of bacteria is called
A
Glycocalyx
14
Q
Gram positive exterior cell structure, color, charge
A
- Thick peptidoglycan layer surrounding cell membrane
- Stain purple
- Contain technical acids which create negative charge
15
Q
Gram negative outer cell structure, and color and any other defining features
A
- Thin peptidoglycan layer surrounds cell membrane
- outer membrane (OM) surrounds peptidoglycan layer
- lipopolysaccharaide (LPS) embedded in OM composed of lipid A and O specific polysaccharide = endotoxins
- lipid A is toxic portion of LPS
- stain pink
16
Q
Acid fast bacteria cell structure, color:
A
Cell wall with high lipid content that resists Gram staining
Note: requires unique dyes and heat to stain
17
Q
Mycobacterium
A
Genus in which all species are acid-fast
E.g. M. Tuberculosis and M. Leprae
18
Q
Cells that have NO cell wall exhibit a _______ cell structure because of a high ____________ content
A
Rigid; sterol
Sterol = waxy solids
19
Q
Plasma membrane is the site of what activity
A
Oxidative phosphorylation for ATP synthesis
NOTE: only aerobic species (use O2)
20
Q
Where are the enzymes that are used for DNA replication in a bacteria?
A
Cell membrane
21
Q
What extrudes from cell membrane and acts as receptors in cell metabolism and cell communication?
A
Proteins
22
Q
What is a mesome?
A
Invagination of cytoplasmic membrane that can form into vesicles and plays possible role in cell division
Also increases surface area
23
Q
What is periplasmic space
A
Space between inner and outer membranes in Gram negative cells
24
Q
What structures are the cytoplasm of bacteria?
A
Nucleiod
Plasmid (DNA)
Ribosomes
Storage granules
25
Region of bacteria cell containing DNA is called what
Nucleiod
26
Is there a nuclear membrane?
No
27
Structure inside the cell that is small extrachromosomal DNA with autonomous replication
Plasmid
Note: plasmids can be transferred between cells during conjugation and often carry antibiotic resistance genes
28
Organelles composed of ribosomal RNA and protein and are sites of protein synthesis are called what
Ribosomes
29
External structures of bacteria include
Flagella
Pili (aka fimbriae)
Capsule - slime layer, Glycocalyx
Endospore
30
What external structure of cell is used for locomotion
Flagella
31
Counterclockwise rotation of flagella produces ___ motion while clockwise rotation produces ___
Forward; tumbling
32
What serves as adherence factors on the external structure of a bacteria?
Pili/fimbrae
33
2 types of pili
1 - sex pili, transfer plasmids
| 2 - attachment pili, shorter, slow cell to attach to surfaces e.g. host tissue
34
What is a unique dormant cell type produced by some bacteria in response to adverse conditions?
Endospore
35
What is sporlation?
When conditions are not favorable cell forms endospore
36
What is germination
When conditions are favorable, returns to metabolically active cell (vegetative)
37
Why are endospores important (3)?
1 - allow cell to survive harsh environmental conditions
2 - high virulence factor (resistant to high temps e.g. boiling)
3 - play roll in botulism, tetanus, gangrene, anthrax
38
Father of taxonomy, classification system with 2 kingdoms (who?)
Linneaus
39
Classification system with 6 kingdoms (who?)
Woese
40
3 domain system due to comparison of DNA sequence. Name the 3
Bacteria
Archaea
Eukarya
41
Bacterial nomenclature:
King Puffs Chest. Oozing Footballs Gambles SavingS
```
Kingdom
Phylum
Class
Order
Family
Genus
Species
Strain
```
42
What morphological characteristics (5) serve as identification markers for bacteria?
- Colony characteristics (what does the community look like?)
- Shape of cell
- Capsule? endospore?
- Staining (G+, G- or neither)
- Flagella - movement? (And arrangement of it)
43
Other than morphological characteristics, what are other ways (7) to tell bacteria apart from each other?
Biochemical testing - test for substrates e.g. sugars
Molecular taxonomy - size of genome, protein similarity, etc
Diagnostic molecular pathology
Polymerase chain reaction
Immunological tests -serotype indicates if it possesses specific set of antigens
Bacteriophage typing
Antibiotic sensitivity testing
44
An organism’s ______ indicates that it possesses a specific set of antigens
Serotype (immunological testing)
45
What is bacteriophage typing?
Phage is a virus that infects bacterium. Phages are host specific, so if you figure out what phage can infect a microbe, you can deduce the bacteria involved
46
Energy source of bacteria?
ATP (adenosine triphosphate)
47
Catabolism
Breakdown of carb, lipid, protein
48
Anabolism
Synthesis of cellular components
49
What metabolism of glucose occurs in the presence or absence of oxygen and 1 molecule of glucose is converted to 2 molecules of pyruvate?
Glycolysis
50
TCA cycle results in a net gain of:
2 ATP
6 NADH
2 FADH2
51
Glycolysis results in a net gain of
2 ATP
| 2 NADH
52
The final e- acceptor is what?
Oxygen
53
The use of reducing power of NADH and FADH2 to synth ATP is called
Oxidative phosphorylation
54
Chemiosmotic theory
ATP is synthesized as a result of proton motive force generated by passing electrons along e- transport chain
55
Aerobic respiration
Process of transferring e- from NADH and FADH2 to oxygen
56
Anaerobic respiration
Without O2, e- transferred to an inorganic terminal electron acceptor such as sulfur
57
Accumulations of highly molecular weight polymers that store glycogen and other energy resources are called
Storage granules
| AKA inclusion bodies AKA granular inclusions
58
Fermentation
Absence of O2, e- transferred to organic terminal electron acceptor
Note: fermentation is used by organisms that can’t respire
59
What is the ATP yield from catabolism of glucose in aerobic respiration, anaerobic respiration, and fermentation?
Aerobic respiration = 38 ATP
Anaerobic respiration = 30 or less ATP
Fermentation = 2-4 ATP
60
What temperature do psychrophiles prefer?
-5 to 15˚ C
Psychro means “cold”
61
What temperature do mesophiles prefer?
25 - 45˚ C
E.g. E. Coli, in other words... they like human body temp which is 37˚C
62
Human body temp in C
37˚
63
What temperature do thermophiles prefer?
45 to 70˚C
E.g. hot springs and compost heaps
64
What temperature do hyperthermophiles prefer?
Over 70˚C
E.g. hot springs, boiling water
65
Oxygen requirement between obligate aerobes, obligate anaerobes, facultative anaerobes, microaerophiles and aerotolerant anaerobes
```
Obligate aerobes: need O2
Obligate anaerobes: killed if O2
Facultative anaerobes: better if O2 is around, but survives if not
Microaerophiles: require small amt O2
Aerotolerant anaerobes: indifferent
```
66
Toxic derivatives of oxygen?
Superoxide
Hydrogen peroxide
OH
67
What requires O2 as final electron acceptor and uses O2 to generate energy?
Obligate aerobes
68
What uses fermentation or anaerobic respiration in absence of O2 AND will die in O2 environment?
Obligate Anaerobes
69
What grows best in O2 but can grow without it?
Facultative anaerobe
70
What requires small amounts of O2 to perform aerobic respiration?
Microaerophiles microbes
71
What can grow in the presence of O2 but does not use it for energy and uses fermentation (instead of aerobic or anaerobic respiration)?
Aerotolerant anaerobes
72
What lives and multiplies from pH 5-8
Neutrophils
73
What lives and multiplies at pH below 5.5?
Acidophiles
74
What lives and multiplies at or above pH 8.5?
Alkalophile
75
Osmotolerant bacteria
Tolerant of high salt environments (up to 10%)
76
What requires high levels of salt to live and multiply more than 10%?
Halophiles
77
A population of organisms descended from a single cell and separate from all other species
Pure cultures
78
Agar-agar is derived from what
Seaweed
79
Koch’s lab assistant created dishes that agar-agar is in, name
Petri dishes // Julius Richards Petri
80
After a bacterial cell gets big and duplicates itself, then it divides. This is called
Binary fission
It’s asexual cell division that happens frequently.
81
3 steps of binary fission
1. Mesosome partitioned
2. Septum
3. 2 daughter genomes
82
Time it takes for a population to double in number is the
Generation time
83
Bacterial growth in laboratory conditions: in a closed system the population growth follows a pattern of stages called a
Growth curve
84
4 phases of growth curve
1. Lag phase (latent) — “ramp up,” recruiting macromolecules & ATP
2. Exponential phase (log) — cells divide all day, ‘er day
3. Stationary phase — cells ate all their food and are chilling
4. Death phase — population dies as they realize they really have no more food
85
How can you measure growth (2)
1. Count them directly with microscope and hemacytometer
| 2. Count them indirectly with serial dilution
86
What is composed of 4 nucleotides? And what are the nucleotides?
DNA
Adenine, thymine, guanine, cytosine
87
What are the DNA nucleotide pairs?
A-T adenine-thymine
G-C guanine-cytosine
(Recall this is different from RNA which substitutes Uracil in place of Thymine)
88
A set of 3 nucleotides on a single strand (codon) encodes a specific
Amino acid
89
Replication of DNA begins at nucleotide sequence called
Ori
AKA Replication origin
90
Because replication goes in [____’ to _____’] direction on a DNA strand, it results in one strand being synthesized continuously called the ____________ strand. The strand that is synthesized discontinuously in pieces is called the ________ strand, and the pieces are referred to as _________ fragments.
5’ to 3’
Leading strand
Lagging strand
Okazaki fragments
91
How does gene expression work (central dogma)?
DNA —> RNA —> protein
Information passes from the genes to the RNA copy of the gene and the RNA copy directs the sequential assembly of a chain of amino acids.
92
RNA nucleotides are what?
A-U Adenine-Uracil
G-C Guanine-Cytosine
(Recall this is different from DNA which has Thymine instead of Uracil)
93
RNA moves along DNA to create ____ which is complementary to
mRNA; DNA
New mRNA is moved to ribosomes for translation.
94
Translation stops when RNA polymerase reaches
Stop signal on DNA
95
What is the process of synthesizing proteins that occurs more or less simultaneously with transcription? And where does this process happen?
Process: Translation
Location: Ribosomes
96
At the beginning of a gene called a _______, mRNA start doing its thing.
Promoter
97
Want to be able to switch on/off transcription. This is controlled by what? (This is unique to bacteria)
Operon
This is a group of genes that includes an operator, common promoter, 1+ structural genes that are controlled as a unit to produce mRNA
In humans, we have 1 promoter for each gene. Bacteria have 1 promoter for many genes.
98
What is an operon (group of genes - 3) in bacteria?
- operator
- common promoter
- 1+ structural genes that are controlled as a unit to produce mRNA
99
Bacteria frequently have 1+ gene encoded on 1 RNA using only 1 promoter, why?
Because transcription and translation are tightly linked
100
Operators/operons come in 2 flavors:
- Inducible operons: always OFF, must be turned ON
| - Repressible: always ON must be turned OFF
101
Amino acids are assembled into growing ________ _______ that, when folded, make a protein.
Polypeptide chain
102
Inducible operon requires ________ to prevent a _________ protein from binding to operator.
inducer; repressor
And repressible operon requires the operator be bound by a repressor.
103
How do end products affect enzymes early in the gene transcription pathway to prevent production of end product?
Feedback inhibition
104
Spontaneous mutations vs induced mutations
Spontaneous mutations:
Not very common. Happens naturally.
Induced mutations:
— common, they are linked to UV light or radiation or exposure to chemical
105
What is the spontaneous mutation that involves an incorrect base being incorporated into the DNA during replication?
Base substitutions
Can lead to:
- point mutation (just 1 base is changed)
- missense mutation (substitution of different a.a. in protein) or
- nonsense (creates stop codon instead of a.a.)
106
What is the spontaneous mutation that involves removal or addition of nucleotides?
Deletion and insertion
107
In spontaneous deletion/insertion mutation, the risk is that you shift the condones/sequence and end up with a different mRNA and a different amino acid. This is called
Frameshift mutant
108
What is the spontaneous mutation where a segment of DNA spontaneously jumps from 1 site to another in the same OR different DNA molecules?
Transposons
AKA jumping genes
109
What are the (2) induced mutations?
Chemical mutagens — alters binding of DNA molecule
Radiation — UV (causes thymine dimers) and X-Ray (causes single and double stranded breaks in DNA)
110
What are the 3 types of spontaneous mutation base substitutions? Describe what happens in each.
Point mutation: 1 base change
Missense mutation: change out amino acid
Nonsense mutation: creates stop codon
111
UV light causes what?
Thymine dimers
112
X-ray causes what
Single and double stranded breaks in DNA
113
How do bacteria repair mutations (2)? Describe
Bacteria employ mismatch (excision repair) as well as SOS repair
Excision involves an enzyme cutting the damage DNA strand out and repairing the gap and then a ligase seals the “scar tissue” nick.
SOS repair is used for severely damaged DNA. It involves skipping over the damaged DNA
114
How best to study mutants?
Induce mutation and study specific types
115
Nutritional mutants: cells that grow without added growth factors
Prototroph
Proto “first”
Trophos “feeder”
*self sufficient*
116
Nutritional mutants: cells that grow ONLY WITH added growth factors from the lab
Auxotrophs
Auxillium “help”
Trophos “feeder”
117
Conditional lethal mutants are mutants defective for the synthesis of
Essential macromolecule under specific conditions (e.g. temperature)
118
Griffith noticed that some unknown compound was transforming bacterial cells and thus, transformation. Explain the phenomenon and what transformation is, as demonstrated by Griffith.
The unknown substance that was transforming bacterial cells was DNA.
So DNA is “naked” in the cell. When cell dies the DNA is released and taken up by recipient cells which causes a change in that 2nd cell.
119
Recipient cells that take up DNA must be described as
Competent
120
Many populations are naturally competent during what phase of growth?
Log phase (phase 2, exponential phase)
121
How can competence be induced (2)
Hint: think (1) chemically and (2) mechanically
CaCl2 treatment
Electrical current: electroporation
122
Conjugation requires contact. DNA transferred in 2 ways
1 - plasmid DNA
| 2 - chromosomal DNA
123
What is the process whereby transfer of bacterial genes from cell to cell via a bacteriophage?
Transduction
124
Bacteriophages can interact with cells in 2 ways
Lytic
| Lysogenic
125
Lytic cells
Virus attaches to host and injects DNA. Sometimes they get right into the cell. Good guy host gets taken over by virus and will make a ton of viruses. So many virus bodies inside the host that the host cell bursts and dies... “avenge me!”
126
Lysogenic cycle
Zombies.
Does the same thing As lytic cycle in the beginning. However, this time the genetic material stays hidden. The good guy host unknowingly makes new cells with their own PLUS the virus’s genetics. And then the virus turns the switch ON and all the Sleeper Hosts turn into zombies.
127
There is lytic and lysogenic, so there are 2 possibilities for transduction. What are they?
Generalized — during production of making new viruses accidents happen. Sometimes only bacterial DNA is packaged. Still infects cells, but its just more bacterial DNA — nothing else happens.
Specialized — phage packages both viral AND bacterial chromosomal DNA. It packages specific chromosomal DNA near where the viral DNA integrated during lysogenic phase.
128
In generalized transduction, the phage serves as a
DNA vector (carries DNA)
129
What is the use of biological techniques to solve practical problems and produce useful products?
Biotech
130
Infection that literally means “brought forth by a healer”
Iatrogenic
Used to refer illness caused by or resulting from medical treatment
Iatros means “physician”
131
What kind of infection is a result of treatment in a hospital but is secondary to patient’s original condition?
Nosocomial infection
Nosokomos “person who tends the sick”
132
Sources of iatrogenic/nosocomial infection (3)
Touching people, blood, etc (direct)
Fomites (indirect)
Airborne transmission (indirect)
133
Ways to prevent and control iatrogenic/nosocomial infection (3)?
Disinfection/treatment with antiseptics
Hand washing
Monitoring patient population
134
Absence of all life
Sterilization
135
Killing/removing pathogens
Disinfection
136
Disinfectant applied to tissue
Antiseptic
137
Substance that kills/removes only bacteria
Bactericide
138
Severe infection leading to systemic immune response
Sepsis
139
Using aseptic technique
Asepsis
Aseptic techniques are employed to avoid microbial contamination E.g. boiling
140
Inhibition of microbe growth
Microbiostasis
141
Range of activity against microbes
Spectrum
| mass murder
142
Drugs tested to determine lowest concentration at that inhibits microbe-called MIC (minimum inhibitory concentration)
Activity
143
Use of 1+ antibiotic to increase spectrum or killing effect
Combination therapy
144
Increased killing effect by using multiple antibiotics
Synergism
145
1 antibiotic interferes with action of another
Antagonism
146
Methods of sterilization (absence of all life)
Moist heat — steam, boiling water
Autoclave — steam with pressure
Dry heat — flame, oven
147
There are 5 classes of antibiotics, what are they?
- Inhibitors of cell wall synthesis
- Inhibitors of cell membrane
- Inhibitors of protein synthesis
- Inhibitors of nucleic acid synthesis
- Antimetabolites
148
Inhibitors of cell wall synthesis work by
Preventing cross-linking of peptidogycan by binding to enzyme receptor sites
149
Inhibitors of cell wall synthesis (5)
```
Penicillin
Cephalosporins
Bacitracin
Vancomycin
Isomiazid
```
150
Inhibitors of cell wall membrane (1) and how does it work
Polymyxin B & E; replace Mg2+ and Ca2+ from membrane lipids and distrusts structure of bacterial cell membrane
151
Inhibitors of protein synthesis (4)
Streptomycin
Tetracycline
Chloramphenicol
Erythromycin
152
Inhibitors of nucleic acid synthesis (2)
Rifampin — used for TB
| Quinolones
153
Antimetabolites (1)
Sulfonamides ( Sulfa drugs)
E.g. used to treat mycobacterium leprae (leprosy)
154
Clinical problems with antibiotic use (5)
- symptoms cease, infection continues
- affects normal flora
- microbes become resistant
- toxicity possible
- sensitization - develop rashes, fever, anaphylaxis
155
What part of a bacteria enables it to survive harsh environmental conditions and makes it have a high virulence factor?
Endospores
High virulence means resistant to high temps e.g. boiling
156
How much O2 do microaerophiles require? What what does higher concentrations do?
2-10%; inhibit
157
What kind of mutant is defective for the synthesis of an essential macromolecule under specific conditions (e.g. temperature)?
Conditional lethal mutants
158
What would you induce in a bacterial cell if you gave it either a CaCl2 treatment or electrical current (e.g. electrophoration)
Competence in a recipient cell to be able to take up DNA
159
What antibiotic initially fights Staphylococcus aureus through cell wall synthesis?
Vancomycin
Damages kidney, nerve deafness, skin rashes, thrombophlebitis
160
What antibiotic is active against mycobacteria only through inhibition of cell wall synthesis?
Isoniazid
Inhibits synthesis of mycolic acids in cell walls of mycobacteria
161
What “vixen” bacteria replaces Mg2+ and Ca2+ from membrane lipids disrupting the structure of bacterial cell membrane?
Polymyxin B and E
Topical use only because its so toxic
162
What antimetabolite is a precursor to antibiotics, antimicrobial agents derived from sulfonic acid?
Sulfonamides (sulfa drugs)
163
What antimetabolite inhibits folic acid synthesis?
Sulfa drugs
