Ch 5: Microbial Metabolism

Question 1

According to Collision theory, what 3 factors determine whether a chemical reaction will occur from a collision?

Answer 1

1. Molecules need to collide with enough energy
2. Speed of the molecules
3. Orientation of the molecules

Question 2

How much can enzymes increase reaction rates?

Answer 2

10⁸ - 10¹⁰ times

Question 3

What is the “turnover number” of an enzyme?

Answer 3

The max number of substrate molecules an enzyme converts to product per second

Question 4

What is the turnover number of DNA polymerase I?

Answer 4

15

Question 5

What is the turnover number of lactate dehydrogenase?

Answer 5

1000

Question 6

What is the turnover number for carbonic anhydrase?

(CO₂ + H₂O → HCO₃ + H⁺)

Answer 6

500,000

Question 7

Is nicotinamide adenine dinucleotide (NAD⁺) used in catabolic or anabolic reactions?

Answer 7

Catabolic

Question 8

Is nicotinamide adenine dinucleotide phosphate (NADP⁺) used in catabolic or anabolic reactions?

Answer 8

Anabolic

Question 9

What are some examples of inorganic cofactors?

Answer 9

Iron

Copper

Zinc

Calcium

Cobalt

Manganese

Magnesium

Question 10

What conditions will denature proteins? (6)

Answer 10

High temperatures

Change in pH

Detergents

Heavy metal ions

Alcohol

Salts

Question 11

Proteins can potentially re-nature if ______

Answer 11

they have not coagulated

Question 12

What is the function of sulfanilamide?

Answer 12

Competitive inhibitor of dihydropteroate synthase and prevents the synthesis of folic acid in bacteria

Question 13

What other molecule does sulfanilamide mimic?

Answer 13

p-Aminobenzoic acid (PABA)

Question 14

What is the function of ribozymes?

Answer 14

RNA splicing

Question 15

Compare and contrast the Entner-Doudoroff pathway and glycolysis.

Answer 15

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

Question 16

What is the final product from one round of the pentose phosphate pathway?

Answer 16

2 NADPH

No ATP consumed or produced

Question 17

What is the final output for every 2 molecules of acetyl-CoA that enter the TCA cycle?

Answer 17

4 CO₂, 6 NADH, 2 FADH₂, 2 ATP (technically GTP but it’s equivalent)

Question 18

What are the three classes of carriers in the electron transport chain?

Answer 18

Flavoproteins

Cytochromes

Ubiquinones (Q)

Question 19

Name the complexes involved in the electron transport chain. What are the mobile electron carriers?

Answer 19

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

Question 20

Where are the enzymes for the electron transport chain located in prokaryotes vs eukaryotes?

Answer 20

Prokaryotes: plasma membrane

Eukaryotes: inner mitochondrial membrane

Question 21

Which complexes in the electron transport chain actively transport protons across the membrane?

Answer 21

NADH dehydrogenase (I)

Cytochrome bc-1 complex (III)

Cytochrome C oxidase (IV)

Question 22

ATP synthase functions how?

Answer 22

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

Question 23

How many total ATP are produced in prokaryotes from the complete oxidation of one molecule of glucose during aeorbic respiration?

Answer 23

38 ATP

C₆H₁₂O₆ + 6 O₂ +38 ADP + 38 P_i → 6 CO₂ + 6 H₂O + 38 ATP

Question 24

In anaerobic respiration, what is used as an electron acceptor instead of O2? What are their products? (3)

Answer 24

NO₃^- → NO₂^-, N₂ + H₂O

SO₄^- → H₂S + H₂O

CO₂ → CH₄ + H₂0

Question 25

What is homolactic fermentation?

Answer 25

Lactic acid fermentation that only produces lactic acid

Question 26

What is heterolactic fermentation?

Answer 26

Lactic acid fermentation that produces lactic acid and other compounds

Question 27

What is the final electron acceptor of lactic acid fermentation?

Answer 27

Pyruvate

Question 28

What microorganism is commercially important for ethanol production?

Answer 28

*Saccharomyces cerevisiae* | (yeast)

Question 29

What is the evolutionary benefit of ethanol fermentation?

Answer 29

Ethanol is toxic to other microbes. Yeast can then break down the ethanol for energy

Question 30

Bacteria can help clean up oil spills by utilizing what metabolic pathway?

Answer 30

β - oxidation

Question 31

What is the drawback to a typical fermentation test?

Answer 31

It relies on a pH indicator (turns yellow in acid) to detect for acid side-products and not actually ethanol

Question 32

What is a chemotroph?

Answer 32

an organism that uses energy from organic or inorganic compounds (chemicals

Question 33

What is a phototroph?

Answer 33

An organism that uses light as its primary energy source

Question 34

What is an autotroph?

Answer 34

An organism that uses CO₂ for their principal carbon source

Question 35

What is a heterotroph?

Answer 35

An organism that requires an organic carbon source (feeders)

Question 36

What is a saprophyte?

Answer 36

A class of chemoheterotroph that live on dead organic matter

Question 37

What is a parasite?

Answer 37

A class of chemoheterotroph that derives its nutrients from a living host

Question 38

*Thiobacillus ferrooxidans* is a chemoautotroph. How does it get its energy?

Answer 38

It uses the Calvin-Benson cycle to fix CO2 (self-feeder)

Question 39

What are the similarities and differences between photoheterotrophs and photoautotrophs?

Answer 39

Both use light as primary energy source photoheterotrophs require an organic carbon source, but photo autotrophs can fix CO2 with the Calvin-Benson cycle

Question 40

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?

Answer 40

55% ATP 45% lost as heat

Question 41

Besides the production of new cellular components, what other cellular processes use ATP?

Answer 41

1. Creating gradients 2. Active transport 3. Movement (flagellar)