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Microbiology > Exam 2 > Flashcards

Exam 2 Flashcards

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1
Q

Steps of Binary Fission

A

Division Preparation: Enlarging Cell Wall, Cell Membrane, Volume, DNA replication
Septum Begins to Form, Chromosomes move outward, cytoplasmic components are distributed
Complete septum synthesis, cell membrane patches itself
Daughter cells divide

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2
Q

E. coli Plasmid partitioning system

A

Single copy plasmid R1 replicates
ParM is anchored to ParC and ParR which attach to the origin of each plasmid
ParM elongates pushing each plasmid to opposite poles of the dividing cell

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3
Q

C. Crestentus Chromosome partitioning system

A

ParA is an ATPase, drives the movement of chromosomes to other end
Par B is a DNA binding protein, binds ParS
ParS are binding sites for ParB

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4
Q

ParC/R

A

attach at origin of plasma in E. coli, attach to ParM (Plasmid partitioning)

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5
Q

ParM

A

elongates the E. coli cell (Plasmid partitioning)

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6
Q

ParA

A

ATPase, elongates the cell and pushes chromosomes further (Chromosome partitioning)

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7
Q

ParB

A

DNA binding protein, Binds Par s (Chromosome partitioning)

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8
Q

Z ring

A

Divisome construction, scaffolding

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9
Q

FtsZ

A

Z ring formation

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10
Q

Par s

A

Binding site for ParB (Chromosome partitioning)

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11
Q

MinD/C/E

A

regulates location of FtsZ ring, ensures midpoint

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12
Q

Cytoplasmic Stage

A

UDP attaches to NAG, UDP-NAG converts to UDP-NAM via PEP

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13
Q

Membrane Stage

A

NAM is removed from the UDP and attaches to bactoprenol, NAG is removed from the UDP and is attached to NAM -> bactoprenol-NAM-NAG (lipid II), peptidoglycan synthase flips to the other side of the membrane, bactoprenol is removed and recycled by dephosphorylation

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14
Q

Extracellular Stage

A

Crosslinking of the transpeptidase

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15
Q

Vancomycin

A

attaches to the last two amino acids to inhibit crosslinking

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16
Q

Penicillin

A

competitively inhibit transpeptidase, from the fungus

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17
Q

Cephalosporins

A

competitively inhibit transpeptidase, from the fungus

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18
Q

Sulfonamides

A

folic acid synthesis, prevents purine synthesis

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19
Q

Quinolones

A

synthetic, inhibits DNA gyrase and topoisomerase II

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20
Q

Azoles

A

antifungal, block last step in synthesis, clotramidazol

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21
Q

Aminoglycosides

A

disrupt peptide elongation during translation, 30S subunit

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22
Q

Tetracyclines

A

similar to aminoglycosides, only bacteriostatic

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23
Q

Macrolides

A

bind to 50S ribosomal subunit

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24
Q

Trimethoprim

A

folic acid synthesis, prevents purine synthesis

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25
Polymyxin B
binds to plasma membrane and disrupts structure and permeability
26
Polyenes
antifungal, bind to ergosterol, nystatin
27
Explain Biofilm formation
Substratum pre-conditioning by ambient molecules Cell deposition Cell absorption Desorption Cell-to-cell signaling Convective and diffusive transport of O2 and nutrients Replication and growth Secretion of polysaccharide matrix Detachment, erosion, sloughing
28
Biofilm formation + pros/cons
Pros (for microbe): enhanced protection from environment, abx res, nutrient acquisition Cons: ABX resistance, gene transfer, super bacteria, persister microbes
29
Explain Quorum Sensing
HSL = AHL High Density = intake, express Low Density = release, attract
30
Explain ways to quantify microbial growth
Cell Counter - culture-based Colony Forming Units - culture-based Quantitative PCR - genomic 16S ribosomal RNA sequencing -> not a qualitative method, genomic
31
Calculate Growth
G = 1/k (gen doubling time) K = n/t (growth rate constant)
32
Halotolerant
S. aureus (3-4 NaCl)
33
Psychrophiles
15 C, arctic ocean, 0-20 C
34
Extreme halophile
H. salinarum (15+ NaCl)
35
Halophile
A. fischeri (6 NaCl)
36
Non Halophile
E. coli (0 NaCl)
37
Barotolerant
pressure adversely affects but not as much as non tolerance
38
Piezophilic
pressures greater than 1 atm (undersea)
39
Osmophiles
adaptation to hypertonic environments, high sugar conc
40
Psychrotrophs
22 C
41
Alkaliphiles
exchange internal sodium ions for external protons
42
Neutrophiles
exchange potassium for protons using antiports
43
ROS Species
O2, O2-, O2-2 (Peroxide), Hydrogen Peroxide, OH, OH-
44
Sterilization
all living destroyed
45
Disinfect
killing of disease causing pathogens
46
Autoclaves
steam sterilization
47
Air Filter
reduce microbial population in lab
48
Sanitation
reduced to public health standards
49
Antiseptic
inhibition of microbes on living tissue
50
Pasteurization
controlled heating, lowers microbial load, kills pathogens
51
Boiling
destroys vegetative cells
52
Phenolic
denature, disrupt membranes (lysol, tanning)
53
Alcohol
denature, dissolve membrane lipids
54
Halogen
F, Cl, I, salt compounds
55
Aldehydes
highly reactive, cross-link with proteins and amino groups in peptidoglycan
56
Alexander Flemming
penicillin
57
Paul Ehlrich
father of chemotherapy, spirochete responsible for syphilis
58
Explain Therapeutic Index
Larger Index = Better Selective Toxicity
59
Name 4 Major Classes of Chemotherapy
Cell wall inhibitors Ribosome/protein inhibitors Metabolic inhibitors Nucleic acid inhibitors and membrane disruptors
60
Discuss Benefits and Disadvantages of Phage Therapy
Using bacterial viruses to combat bacterial infections, benefits = active against abx resistant bacteria, replicate at site of infection Disadvantages - more research needed, does not work for intracellular pathogens, can transfer toxin genes
61
MIC
lowest concentration resulting in no growth after 16-20 hrs of incubation
62
Disk
wider zone around the abx infused disk = higher susceptibility to the abx
63
Kirby Baurer
small zone = higher MIC (higher min dose till effective)
64
Name 4 Antibiotic Resistance Examples
Modify the target of the antibiotic (penicillin binding proteins) Drug Inactivation (B-lactamases) Alter membrane structure and use efflux pumps to minimize abx concentration in the cell Alternate pathways
65
Order of Temperature Tolerant Microbes
Psychrophiles -> Psychrotrophs -> Mesophiles -> Thermophiles -> Hyperthermophiles
66
How to Control for Microbial Growth
Oxygen Salt Concentration Temperature Radiation pH
67
Name the two antimicrobials that act as inhibitors for enzymes
Sulfonamides, trimethoprim
68
Difference between FADH2 and NADH
Difference in reduction potential between these two electron carriers, enter the ETC later, NADH results in more H+ being pumped out
69
Define Aerobic bacterial ETCs
Located in the plasma membrane, in gram negative bacteria they are located in the inner membrane, shorter, results in fewer protons pumped across the membrane and less ATP produced, similar and different protein carriers, ATP synthase functions in the same way
70
Discuss E. coli branched ETC
High aeration, log phase, bo branch Low aeration, stationary phase, bd branch
71
Discuss P. denitrificans ETC
Nitrate reduction to N2 is a multi-step process that ultimately takes place in the periplasm, hydrogens actually taken from the periplasm by NOR to reduce NO -> N2O, negatively effects hydrogen gradient
72
Discuss total ATP Production
Eukaryotes - max 32 ATP, 2.5 ATP per NADH Bacteria - 1.3-0.67 ATP per NADH Bacteria produce much less ATP because of the smaller ETC which produces less ATP due to fewer protons being transferred across the membrane
73
Fermentation
Chemoorganotrophs can’t respire under certain conditions, NADH is oxidized back to NAD+ to keep glycolysis going
74
SCFA
60 acetate: 20 propionate: 20 butyrate, common receptors are GPR1 and GPR43
75
HDAC
HDACs deacetylate/remove actively groups, makes DNA wound tighter to histone, inhibition of HDAC = more gene expression
76
Asthma Pathway
Acetate enters bloodstream -> travels to lungs -> binds GPR41/43 -> signaling cascade inhibits HDACs -> increased expression of genes like Foxp3 -> marker for T-regs -> suppression of airway inflammation
77
Nitrifying
Nitrifying bacteria (chemolithotrophs) - use oxidation of nitrogenous compounds as e- source = adds nitrogen to environment
78
Denitrification
(organotrophs) use nitrate as terminal e- acceptor for anaerobic respiration = deplete nitrogen from the environment
79
Chemolithotrophs
Oxidize inorganic compounds instead of organic compounds to produce ATP, still have O2 as final e- acceptor, microbes do not oxidize sugars to produce electrons, oxidize hydrogen and nitrogen compounds (rocks)
80
Horizontal v. Vertical Gene Transfer
Only competent microbes can transfer horizontally
81
Synonymous mutation
altered codon, same amino
82
Missense conservative
altered codon, chemically similar amino
83
Missense non conservative
altered codon, chemically different amino
84
Nonsense
codon signals chain termination
85
Frameshift Insertion/Deletion
moves reading frame, very bad
86
Auxotroph and Prototroph
Auxo - inactivates biosynthetic pathway Prototrophic - acquire of a secondary mutation that makes up for first mutation
87
Replica Plating
Original culture is stamped, applied to normal media and minimal media, colonies that grow on minimal media plus amino are auxotrophic
88
3 Types of Horizontal Transfer
Conjugation - bridge Transduction - Viral Transformation - uptake of free DNA
89
fate of donated DNA
DNA is integrated, plasmid self-replicates, donor DNA cannot replicate, host restricts new DNA
90
F-factor plasmid, Hfr, F-, F’
F-factor plasmid - bacteria need this plasmid to carry out conjugation, F+ if positive, F-factor can be inserted into the bacterial genome from the plasmid or excised. Hfr - high frequency recombinants, have F factor integrated into their chromosome Hfr x F- conjugation cannot equal an F+ cell only recombinant F’ cells - F factor deintegrates from the Hfr host chromosome
91
Who is Frederick Griffith?
Discovered natural transformation, smooth fatal rough nonfatal, dead rough plus alive smooth are fatal
92
Discuss the Bacterial Transformation Mechanism
DNA fragments bind to cell surface receptor Extracellular endonuclease cuts into DNA One strand is degraded and a single strand is transported into the cell The DNA strand aligns itself with a homologous region on the bacterial chromosome The DNA strand incorporated via homologous recombination
93
HGT mediated by viruses
Bacterial viruses can reproduce in one of two ways and both result in HGT between bacterial cells
94
lytic v lysogenic cycles
Lytic - lyse cells Lysogenic - dormant until stressed
95
generalized and specialized transduction
Generalized - a virus produces new phage particles during lytic cycle, some host cell DNA can be carried off in the phage head Specialized - a prophage from the lysogenic cycle exits from the bacterial genome, leaves from genes behind and takes some bacterial genes with, infection of other cells but new phage will not kill
96

Microbiology (13 decks)

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