Ch 5: Microbial Metabolism Flashcards
According to Collision theory, what 3 factors determine whether a chemical reaction will occur from a collision?
- Molecules need to collide with enough energy
- Speed of the molecules
- Orientation of the molecules
How much can enzymes increase reaction rates?
108 - 1010 times
What is the “turnover number” of an enzyme?
The max number of substrate molecules an enzyme converts to product per second
What is the turnover number of DNA polymerase I?
15
What is the turnover number of lactate dehydrogenase?
1000
What is the turnover number for carbonic anhydrase?
(CO2 + H2O → HCO3 + H+)
500,000
Is nicotinamide adenine dinucleotide (NAD+) used in catabolic or anabolic reactions?
Catabolic
Is nicotinamide adenine dinucleotide phosphate (NADP+) used in catabolic or anabolic reactions?
Anabolic
What are some examples of inorganic cofactors?
Iron
Copper
Zinc
Calcium
Cobalt
Manganese
Magnesium
What conditions will denature proteins? (6)
High temperatures
Change in pH
Detergents
Heavy metal ions
Alcohol
Salts
Proteins can potentially re-nature if ______
they have not coagulated
What is the function of sulfanilamide?
Competitive inhibitor of dihydropteroate synthase and prevents the synthesis of folic acid in bacteria
What other molecule does sulfanilamide mimic?
p-Aminobenzoic acid (PABA)
What is the function of ribozymes?
RNA splicing
Compare and contrast the Entner-Doudoroff pathway and glycolysis.
EDP: produces 1 ATP, 1 NADH, and 1 NADPH; has a lower activation energy
Glycolysis: produces 2 ATP and 2 NADH; has a higher activation energy
What is the final product from one round of the pentose phosphate pathway?
2 NADPH
No ATP consumed or produced
What is the final output for every 2 molecules of acetyl-CoA that enter the TCA cycle?
4 CO2, 6 NADH, 2 FADH2, 2 ATP (technically GTP but it’s equivalent)
What are the three classes of carriers in the electron transport chain?
Flavoproteins
Cytochromes
Ubiquinones (Q)
Name the complexes involved in the electron transport chain. What are the mobile electron carriers?
I: NADH dehydrogenase
II: Succinate dehydrogenase
III: Cytochrome bc-1 complex
IV: cytochrome C oxidase
V: ATP synthase
Mobile electron carriers: Q and cytochrome C
Where are the enzymes for the electron transport chain located in prokaryotes vs eukaryotes?
Prokaryotes: plasma membrane
Eukaryotes: inner mitochondrial membrane
Which complexes in the electron transport chain actively transport protons across the membrane?
NADH dehydrogenase (I)
Cytochrome bc-1 complex (III)
Cytochrome C oxidase (IV)
ATP synthase functions how?
Protons pumped out by complexes I, III, and IV can only get back across the membrane via ATP synthase, which drives the synthesis of ATP
How many total ATP are produced in prokaryotes from the complete oxidation of one molecule of glucose during aeorbic respiration?
38 ATP
C6H12O6 + 6 O2 +38 ADP + 38 Pi → 6 CO2 + 6 H2O + 38 ATP
In anaerobic respiration, what is used as an electron acceptor instead of O2? What are their products? (3)
NO3- → NO2-, N2 + H2O
SO4- → H2S + H2O
CO2 → CH4 + H20
What is homolactic fermentation?
Lactic acid fermentation that only produces lactic acid
What is heterolactic fermentation?
Lactic acid fermentation that produces lactic acid and other compounds
What is the final electron acceptor of lactic acid fermentation?
Pyruvate
What microorganism is commercially important for ethanol production?
Saccharomyces cerevisiae
(yeast)
What is the evolutionary benefit of ethanol fermentation?
Ethanol is toxic to other microbes. Yeast can then break down the ethanol for energy
Bacteria can help clean up oil spills by utilizing what metabolic pathway?
β - oxidation
What is the drawback to a typical fermentation test?
It relies on a pH indicator (turns yellow in acid) to detect for acid side-products and not actually ethanol
What is a chemotroph?
an organism that uses energy from organic or inorganic compounds (chemicals
What is a phototroph?
An organism that uses light as its primary energy source
What is an autotroph?
An organism that uses CO2 for their principal carbon source
What is a heterotroph?
An organism that requires an organic carbon source (feeders)
What is a saprophyte?
A class of chemoheterotroph that live on dead organic matter
What is a parasite?
A class of chemoheterotroph that derives its nutrients from a living host
Thiobacillus ferrooxidans is a chemoautotroph. How does it get its energy?
It uses the Calvin-Benson cycle to fix CO2 (self-feeder)
What are the similarities and differences between photoheterotrophs and photoautotrophs?
Both use light as primary energy source
photoheterotrophs require an organic carbon source, but photo autotrophs can fix CO2 with the Calvin-Benson cycle
During the complete oxidation of glucose to CO2 and H2O, how much energy is trapped in the bonds of ATP and how much is lost as heat?
55% ATP
45% lost as heat
Besides the production of new cellular components, what other cellular processes use ATP?
- Creating gradients
- Active transport
- Movement (flagellar)
