Micro final Flashcards
1
Q
psychrophile
A
- below 15C
- ice formation detrimental so produce cryoprotectants (trehalose) to prevent ice formation in cytoplasm
- unsaturated fatty acids and less intermolecular forces to increase fluidity and flexibility
2
Q
thermophiles/hyperthermophile
A
- 40-70C, 60-100C
- cytoplasmic membrane has saturated FA to decrease fluidity
- stable enzymes/proteins that resist denaturation, have MORE IM forces (H bonds, ionic, hydrophobic, disulfide)
3
Q
hyper thermophilic archaea
A
phospholipids are ether instead of ester linked
4
Q
mesophile
A
10C-45C
5
Q
barophiles
A
- require high pressure to grow, die at higher pressures, quadratic
- deep sea, temp often low too
- polysaturated phospholipids in membranes to increase fluidity
6
Q
barotolerant
A
can grow up to certain pressure, die at higher pressures
7
Q
barosensitive
A
die as pressure increases
8
Q
hypertonic
A
- high salt
- cell shrinks and detaches from cell wall (plasmolysis)
- synthesis of compatible solutes to combat
9
Q
hypotonic
A
- low salt
- cell expands and lysis can occur
- stop import of compatible solutes to combat
- membrane channels open allowing solutes to diffuse out of cytoplasm
10
Q
halophiles
A
- high salt, 3-10%
- low water
- maintain high concentration of inorganic/organic solutes in cytoplasm to lower risk of dehydration
11
Q
extreme halophiles
A
- archaea
- high salt, 15-30%
- adaption of K+ import not Na+
- more asp and glu (- charge acidic amino acids) on surface
- AA interact with K+ to attract water to keep cell hydrated
12
Q
acidophiles
A
- low pH below 5
- cytoplasm at risk of being acidic, may pump protons out of cell or produce enzymes that catalyze reactions that consume protons
13
Q
neutrophiles
A
5-8 pH
14
Q
alkaliphiles
A
- high pH above 8
- cytoplasm at risk of being basic, may pump protons into cell or produce enzymes that catalyze the production of acids
15
Q
cytoplasmic pH
A
has to be neutral to maintain proton motif force
16
Q
pH vs osmolarity adaption
A
osmolarity will change pH
17
Q
obligate anaerobe
A
no oxygen
18
Q
obligate aerobe
A
requires O2
19
Q
microaerophile
A
requires O2 but too much will kill it, ETC not very efficient so will accumulate many oxygen radicals in high O2
20
Q
facultative anaerobe
A
can grow with or without O2, prefers with
21
Q
aerotolerant
A
can grow with or without O2 but only performs fermentation
22
Q
enzymes that detoxify oxygen radicals
A
superoxide dismutase, catalase, peroxidase
23
Q
anaerobic microorganisms growing in lab
A
- sealed container with GasPak, absorbs O2 so non in container
- air locked contained with glove port, pumps N2 gas in
24
Q
sterile
A
no microorganisms present
25
disinfect
remove infectious agents/pathogenic bacteria, non-pathogenic bacteria still present
26
heat
- physical method to control microbial growth
- moist heat, dry heat
27
moist heat
- uses steam > 100C, denatures protein in short period of time
- hydrophobic comes out and bonds with other hydrophobic forming precipitate
- in lab autoclave at 121C for 20 minutes
28
pasteurization
- moist heat
- milk is not sterile, kills bacteria that causes disease and leaves the rest
- 72 C for 15 seconds
29
dry heat
kills by oxidization, Bunsen burner?
30
radiation
- physical method to control microbial growth
- ultraviolet light damages DNA
- bacteria can be very resistant so not used for food often
- expensive
31
filtration
- physical method to control microbial growth
- membranes with 0.2um pore size
- water goes through bacteria stays
32
biocides/disinfectants
- chemical method to control microbial growth
- usually non specific
- normal household products, no prescription
- oxidizers, membrane disruptors, protein denaturants
33
antibiotics
- chemical method to control microbial growth
- kills bacteria only
- target specific cellular structures
- used to treat disease in humans and animals
34
clorox bleach
- active ingredient sodium hypochloride (NaOCl)
- oxidizing agent, inactive proteins and lipids
35
tincture iodine
- active ingredient iodine
- modifies proteins, tyrosine amino acid also oxidizing agent
36
alcohol/hand sanitizers
- ethanol active ingredient
- ethanol dissolves lipid membrane and denatures protein
37
wet ones antibacterial wipes
- active ingredient benzethonium chloride (quaternary ammonium compound)
- positively charged, interact with phospholipids and disrupts cytoplasmic membrane
38
Listerine
- active ingredient thymol (phenol)
- organic compound that kills by denaturing proteins
39
dove soap bar
- active ingredient detergent
- dissolve cytoplasmic membrane, mechanical removal of microorganisms
40
dettol antibacterial soap
- active ingredient triclosan
- triclosan inhibits lipid synthesis enzymes in bacteria and fungi
- household use now banned in US
41
selective toxicity
kills target bacteria and not eukaryotes like human cells
42
penicillin selective toxicity
- inhibit cell wall synthesis by inhibiting peptidoglycan synthesis by inhibiting activity of penicillin binding proteins
- covalently fuse AA chains between NAM
- B-lactam antibiotic
- causes cell to burst
43
vancomycin
- binds to D-ala-D-ala on NAM preventing transpeptidation
- same effect a B-lactam antibiotic but different mode of action
- does not bind to penicillin binding proteins, binds to substrate of penicillin binding protein
44
inhibit protein synthesis
streptomycin, chloramphenicol, tetracycline, erythromycin
45
quinolones
- inhibit DNA synthesis, affect nucleic acid synthesis
- bind DNA gyrase causing gyrase-DNA covalent complex to be stuck at this stage
- prevent DNA polymerase from accessing origin of replication
46
chemical damage of DNA
free radical form of metronidazole reacts with DNA causing DNA breaks
47
polymyxin, antimicrobial peptides
- disrupt cell membranes
- bad for gram negative because of LPS
- gramicidin forms channel through cytoplasmic membrane allowing free diffusion of cations
48
sulfanilamide
- enzyme inhibitors
- PABA required for synthesis of folic acid and essential vitamin
- sulfanilamide binds to enzyme required for folic acid synthesis and inhibits its activity
49
antibiotic resistance mechanisms
- bacteria produce enzymes that modifies antibiotic
- mutation of gene that encodes the antibiotic target
- preventing antibiotics from penetrating bacteria cells or actively pumping antibiotics antibiotics out of cell
50
why are slow growing bacteria (mycobacterium) more resistant to antibiotics
antibiotics target things during cell division, since it grows slowly cannot be stopped during division
51
bacteria in biofilms
- more resistant to antibiotics
- teeth, lungs, hospital equipment
52
metaCyc
database of metabolic pathways
53
catabolism
breakdown of complex molecules into smaller ones releasing energy
54
anabolism
reactions that build complex molecules from smaller molecules, requires energy
55
autotroph
carbon source from CO2
56
heterotroph
carbon source from organic carbon (sugars)
57
photoautotroph
ATP/energy from light
58
chemolithotroph
ATP/energy from minerals
59
chemoorganotroph
ATP/energy from organic compound
60
embden-meyerhoff-parnas (EMP)/glycolytic pathway
- glucose molecule undergoes stepwise breakdown to two pyruvate molecules
- ATP produced from pathway is called substrate level phosphorylation
61
EMP/glycolytic pathway overview
glycolysis prep stage: -2 ATP, 0 NADH
glycolysis E prod.: +4 ATP, +2 NADH
NET: 2 ATP, 2 NADH, 2 molecules pyruvate
62
ED pathway
- modified glycolytic pathway
- commonly used by gut microbiota
- only 1 ATP used in prep
- 1 NADPH produced in prep
- only 1 ATP and NADH in E prod
-NET 1 ATP, 1 NADPH, 1 NADH
63
glycolysis/ED pathway can go into
fermentation or kreb's cycle
64
fermentation
- catabolism without ETC and electron acceptor
- main purpose to recycle NADH to keep glycolysis going
- H from NADH + H+ transformed back to NAD+ for glycolysis
- oxidation of carbon source (glucose) with transfer of e- to organic molecules (pyruvate)
65
fermentation overview
ethanol to lactic acid
0 ATP, -2 NADH, 0 FADH2
66
kreb's/TCA/citric acid cycle
- prok in cytoplasm, euk in mitochondria
- connection through pyruvate breakdown to acetyl-CoA and CO2
- in TCA acetyl-CoA condenses with 4-C oxaloacetate forming citrate, then converted to CO2
67
kreb's cycle overview
- +2 ATP, +8 NADH, +2 FADH2
for each pyruvate:
- 3 CO2 by decarboxylation
- 4 NADH and 1 FADH2 by redox
- 1 ATP by substrate level phosphorylation (sometimes GTP)
68
oxidative phosphorylation
process of electron transport and ATP generation
69
metabolic pathway not completed until
- all carbons of glucose released as CO2
- electrons carried by coenzymes NADH and FADH2 are donated to terminal electron acceptor
70
where is electron transport located
mitochondria, cytoplasmic membrane in bacteria
71
proton motive force
- transfer of H+ through proton pump generates electrochemical gradient
- drives conversion of ADP to ATP in ATP synthase
- know as chemiosmotic theory
72
proton motive force stored energy forms
- electrical potential, arises from separation of charge between cytoplasm and outside cell membrane
- pH difference, ratio of external to internal chemical concentration H+
73
ATP synthesis
- H+ want to move back into cytoplasm
- membrane won't allow charged molecules through
- must flow through ATP synthase and make ATP
74
other functions driven by P+ gradient
ATP synthesis, rotation of flagella, uptake of nutrients, efflux of toxic drugs
75
reduction potential
how readily a redox pair can be reduced/accept electrons
76
gibbs free energy
/\G=-nF (E of e- acceptor - E of e- donor)
n = number of electrons
F = faraday constant
77
ETC overview
1 NADH makes 3 ATP
1 FADH2 makes 2 ATP
78
total ATP with glycolysis, kreb's and ETC?
38 ATP
79
aerobic oxidative phosphorylation initial and final e-
e- donor: NADH->NAD+, FADH2->FAD+
e- acceptor: O2->H2O
80
anaerobic oxidative phosphorylation initial and final e-
e- donor: NADH->NAD+, FADH2->FAD+
e- acceptor: NO3- ->NO2-
81
photosynthesis
- uses light as energy source to drive ETC to produce ATP
- sources of electrons to reduce cofactors can from from: water, aerobic photosystems, anaerobic photosystem I, anaerobic photosystem II
82
NADP and ATP used by photosynthetic bacteria to
fix carbon dioxide
83
aerobic photosynthesis overview
e- donor: H2O->O2
e- acceptor: NADP+->NADP
84
anaerobic photosynthesis I overview
e- donor: H2S->S*, H2->H+
e- acceptor: NADP+->NADPH, NAD+->NADH
85
anaerobic photosynthesis II overview
e- donor: chlorophyll
e- acceptor: chlorophyll
86
chemolithotrophy overview
e- donor: H2->S
e- acceptor: O2->H2O
