exam 2 Flashcards
based on powerpoint slides
what fixes atmospheric N2 to ammonia?
nitrogenase
what oxidizes NH4 to generate energy?
nitrifiers
what use oxidized forms(e.g., nitrate) as alternative e- acceptors in the nitrogen cycle?
denitrifiers
what are the two types of diffusion that are passive?
simple and facilitated
what are the two types of transport that are active?
ABC transporters, coupled transport
what way do solutes move in facilitated diffusion?
move across a membrane from high concentration to low concentration
what is a coupled transport system?
a driving ion moving down its gradient is used to move a solute up its gradient
what type of coupled transport is the lactose transport system?
symport (H+ and lactose move inside the cell at the same time)
what type of coupled transport is the Na+/H+ transport system?
antiport (Na+ enters the cell as H+ is pumped out)
what do uptake ABC transporters do?
transport nutrients
what do efflux ABC transporters do?
“mulitdrug efflux pumps” (idk what this means)
what are the steps of the ABC transportation process?
- solute binds to binding protein and this complex binds to binding protein.
- ATPase activity of one component powers the opening of the channel.
- the solute moves into the cell.
what is the process by which most bacteria divide called?
binary fission
what happens in a continuous culture?
all cells in a population achieve a steady state as bacteria are removed and nutrients are replenished accordingly, allowing for a detailed study of physiology
what ensures logarithmic growth by constantly adding and removing equal amount of culture medium?
chemostat
what type of culture medium is useful for studying growth characteristics of a pure culture?
liquid or broth
what type of culture medium is useful for separating mixed cultures?
agar plate (solid)
what does a fastidious medium require?
blood (remember FASTidious, Edward Cullen is fast and a vampire)
what is the special microscopic slide that is used to count microbes called?
counting chamber
what is FACS and what does it do?
fluorescence-activated cell sorter wherein fluorescent cells are passed through a small opening and then past a laser; detectors measure scattered light to find particle size and shape
what is the viable cell count?
the number of replicating and colony forming units(CFUs)
what is used to find the optical density?
spectrophotometer
what is performed in the pour plate method?
tenfold serial dilutions from liquid culture
what is done once the serial dilution have been performed in the pour plate method?
each dilution is plated on an agar plate
what plate is counted to determine bacterial count?
the one with 30-300 colony forming units (CFU)
what are the “normal” growth conditions?
sea level(1atm), temperature around 20-40 degrees Celsius, neutral pH ~7, 0.9% salt, ample nutrients
what are organisms that occupy habitats outside of normal ecological niche called?
extremophiles
what are barosensitive organisms?
organisms that die as pressure increases
is moist heat or dry heat more effective at killing microorganisms?
moist heat
what is needed to kill the most resistant spores?
a steam autoclave at 121 degrees C at 15 psi for 20 minutes
what is LTLT pasteurization?
low temperature, long time; 63 degrees C for 30 minutes
what is HTST pasteurization?
high temperature, short time; 72 degrees C for 15 seconds
what is UHT pasteurization?
ultra-high temperature; 134 degrees C for 2 seconds; used to sterilize milk and cream
how do cold temperatures affect microbial growth?
they slow growth and preserve strains
what is lyophilization?
freeze-drying
what can micropore filters of 0.2 nanometers remove?
microbial cells but not viruses from soln.
what is ultraviolet (UV) light irradiation used for?
surface sterilization only because it has poor penetrating power
what is gamma ray, e- beam, and X-ray irradiation used for?
irradiating foods and other heat sensitive items
what is ethylene oxide used for?
sterilizing heat and moisture sensitive materials as it is a gas sterilant
what are compounds that are synthesized by one microbe that kill/inhibit the growth of other microbial species?
antibiotics
how does penicillin work?
it mimics the peptidoglycan in the bacterial cell wall causing the cell wall not to form
what is the use of one microbe to control the growth of another?
biocontrol
what is phage therapy?
the use of a virus to target a pathogen to treat infectious disease; an alternative to antibiotics as more diseases are becoming antibiotic resistant
what is the breakdown of complex organic molecules into simpler ones?
catabolism
what is the process of reaction that build cells called?
anabolism
how is energy obtained for anabolism?
through catabolism, usually in the form of ATP
what is the first law of thermodynamics?
energy cannot be created or destroyed, only converted from one form to another
how is the first law of thermodynamic applied to the flow of energy in an ecosystem?
glucose is converted into ATP
what is the second law of thermodynamics?
energy cannot be changed from one form to another without a loss of usable energy
how is the second law of thermodynamics applied to the flow of energy in an ecosystem?
glucose oxidation consumes energy; CO2 is lost to the environment; free energy is lost
is NADH an e- donor or e- acceptor?
e- donor
is NAD+ an e- donor or e- acceptor?
e- acceptor
how much energy does NADH carry compared to ATP?
NADH carries three times as much
what is the chemical reaction for the reduction of NAD?
NAD+ + 2H+ + 2e- –> NADH + H+
what is the reduced form of the flavin adenine dinucleotide?
FADH2 is the reduced form
what is the chemical reaction for the reduction of FAD+?
FAD + 2H+ + 2e- –> FADH2
what is the process wherein polysaccharides are broken down into pyruvate?
glycolysis
what is the process wherein pyruvate is fermented or further catabolized to CO2 and H2O?
TCA cycle
what is the key intermediate of the EMP pathway?
glucose 3 phosphate (G3P)
what is the key intermediate of the ED pathway?
6-P-glucancate
what is the key intermediate of the PPP?
ribulose 5-P
what are the products of the EMP pathway?
2 ATP, 2 NADH, 2 pyruvates
what are the products of the ED pathways?
1 ATP, 2 pyruvates, 1 NADH, 1 NADPH
what are the products of the PPP?
biosynthesis carbon sugar phosphates, 1 ATP, 2 NADPH
where does glycoysis(EMP) occur?
cytoplasm
does glycolysis rely on O2?
no
in stage 1 of glycolysis, energy is invested in the form of 2 ATP that are used to phosphorylate glucose twice. This results in fructose-1, 6-biphosphate which is cleaved to become what?
dihydroxyacetone phosphate(DHAP) and glyceraldehyde-3 phosphate(G3P)
in stage 2 of glycolysis, energy is yielded from the conversion of G3P to two molecules of pyruvate. what does this redox reaction produce?
two molecules of NADH
how many molecules of ATP are produced during stage 2 of glycolysis?
4
what is the net yield of ATP during glycolysis?
2 (4 made - 2 invested)
what is a partial completion of catabolism without the ETS and terminal e- acceptor?
fermentation
what does homolactic fermentation produce?
two molecules of lactic acid
what does ethanolic fermentation produce?
two molecules of ethanol and two molecules of CO2
what does heterolactic fermentation produce?
1 molecule of lactic acid, 1 molecule of ethanol, 1 molecule of CO2
what does mixed-acid fermentation produce?
acetate, formate, lactate, succinate, ethanol, H2, and CO2
what is indicated by a methyl tube turning red?
the organism uses mixed acid fermentation to make acids
what does the Voges-Proskauer test do?
determines if organisms use butylene glycol pathway to produce acetonin
what is a positive VP result?
a deep red color, showing that the organism uses the butylene glycol pathway
what is a negative VP result?
a copper color, showing that the organism does not use the butylene glycol pathway
what does a positive methyl red test look like and mean?
a red color change in medium showing that the bacteria produces mixed-acids during fermentation
what does a negative methyl red test look like and mean?
a yellow color change in medium showing that the bacteria did not produce acid during fermentation
where does the TCA cycle occur in prokaryotes?
cytoplasm
where does the TCA cycle occur in eukaryotes?
mitochondria(the powerhouse of the cell)
how does glucose catabolism(glycolysis) connect with the TCA cycle(Krebs cycle)?
pyruvate(product of glycolysis) is broken down into acetyl-CoA(reactant of TCA cycle) and CO2(lost to environment
what very large multi-subunit enzyme catalyzes the conversion of pyruvate to acetyl-CoA?
pyruvate dehydrogenase complex(PDC)
what is the net reaction for the conversion of pyruvate to acetyl-CoA?
pyruvate + NAD+ + CoA –> acetyl-CoA + CO2 + NADH + H+
what are the products of each pyruvate molecule?
3 CO2, 4 NADH, 1 FADH2, 1 ATP
what are the products of each glucose molecule after the Krebs cycle?
6 CO2, 10 NADH, 2 FADH2, 4 ATP
what are the products of each acetyl-CoA molecule in the Krebs cycle?
2 CO2, 3 NADH, 1 FADH2, 1 ATP
what do the enzymes in the glyoxylate shunt do?
divert isocitrate to glyoxylate
what is incorporated in the glyoxylate shunt to form malate?
a second acetyl-CoA
why are e- donated to bacterial ETS?
to generate ATP via oxidative phosphorylation
how many H+ can be pumped across the membrane per NADH oxidized?
8-10 H+
what is the electrochemical gradient of protons called?
proton motive force (PMF)
how is the mitochondrial ETS different than the bacterial ETS?
- has an intermediate ubiquinol:cytochrome-c oxoreductase complex to transfer e-
- pumps two more H+ per NADH than bacterial ETS
how does the mitochondrial ETS pump two more H+ per NADH than the bacterial ETS?
it has the third proton pump (cyochrome c complex)
what drives the conversion of ADP to ATP in the mitochondrial ETS?
proton motive force through ATP synthase
how many protons are pumped out of the cell per NADH?
10 p+
how many molecules of ATP are produced per NADH?
3 ATP
how many protons are pumped out of the cell per FADH?
6 p+
how many molecules of ATP are produced per FADH2?
2 ATP
from where to where are protons pumped in the mitochondrial ETS?
from the matrix to intermembrane space
what where to where are protons pumped in chloroplasts?
from stroma to thylakoid lumen
who discovered the chemiosmotic theory?
Peter Mitchell
what is the chemiosmotic theory?
cells generate ATP by using the energy stored in an electrochemical gradient of protons (hydrogen ions) across a membrane, essentially harnessing the movement of protons to drive ATP synthesis through a protein complex called ATP synthase
what is the theoretical maximum yield of ATP in eukaryotic cells?
36 ATP
what type of respiration occurs in wetland soil and the human digestive tract?
anaerobic respiration b/c oxygen is scarce
what are the two common e- acceptors for prokaryotes undergoing anaerobic respiration?
nitrate(reduced to nitrite) and sulfate(reduced to sulfite)
the total amount of ATP produced through aerobic respiration is 38 ATP. where does it come from specifically?
4 ATP from substrate-level phosphorylation; 30 ATP from the 10 NADH produced via ETS and ATPase; 4 ATP from 2 FADH produced via ETS and ATPase
where is pyruvate generated?
cytoplasm
how many carbons does pyruvate have?
3
how many carbons does acetyl-CoA have?
2
does the glyoxylate shunt produce ATP?
no, because succinyl-CoA to succinate step is bypassed which normally converts ADP to ATP
what is the NADH production difference from the normal TCA cycle and the glyoxylate bypass?
in the glyoxylate bypass, 2 out of the 3 NADH are not produced
what color will the phenol red tube be in mixed-acid fermentation?
yellow
what color will the phenol red tube be in heterolactic fermentation?
yellow
what color will the phenol red tube be in ethanolic fermentation?
red
what color will the phenol red tube be in homolactic fermentation?
yellow
what happens to the enzymes/proteins of an organism if it gets too hot?
they denature
