Deck 7: Bacterial Metabolism

Question 1

The human genome does NOT code for enzymes that can catabolize

A) cellulose.
B) starch.
C) fatty acids.
D) proteins.

Answer 1

A

Question 2

What molecule is depicted here?

A) ADP
B) ATP
C) NAD+
D) NADH

Answer 2

A

Question 3

Which numbered arrow(s)point(s)to a step that indicates reactions carried out by autotrophs?

A) 1
B) 2
C) 3
D) 1 and 2

Answer 3

A

Question 4

Which metabolic pathway is shown here?

A) Calvin cycle
B) glycolysis
C) oxidative phosphorylation
D) tricarboxylic acid cycle

Question 5

The hydrolysis of a protein into amino acids is an example of

A) anabolism.
B) catabolism.
C) lithotrophy.
D) nitrogen fixation.

Question 6

If cells cannot carry out fermentation or respiration,which numbered box indicates the first step of glycolysis to be affected?

A) 1
B) 2
C) 3
D) 4

Question 7

What catabolite is produced first from the catabolism of starch and cellulose?

A) acetyl-CoA
B) amino acids
C) glucose
D) glycerol

Question 8

Which of the following is true of metabolic reactions?

A) They are all catalyzed by enzymes.
B) They all release energy.
C) Reactions are unique to particular organisms.
D) They always use or produce ATP.

Question 9

Which numbered box most clearly shows a redox reaction?

A) 1
B) 2
C) 3
D) 4

Question 10

An organism gains energy using H₂ as an electron donor and sulfate as an electron acceptor.This organism is categorized as an

A) aerobic lithotroph.
B) anaerobic lithotroph.
C) aerobic organotroph.
D) anaerobic organotroph.

Question 11

During glycolysis glucose is ________ and NAD⁺ is ________.

A) oxidized; reduced
B) reduced; oxidized
C) oxidized; oxidized
D) reduced; reduced

Question 12

In a metabolic reaction involving the conversion of NADH to NAD⁺

A) NADH loses electrons and gains energy.
B) NADH gains electrons and gains energy.
C) NADH loses electrons and loses energy.
D) NADH gains electrons and loses energy.

Question 13

Which statement describes the reaction shown?

A) It is an anabolic reaction.
B) It is a hydrolysis reaction.
C) It is a redox reaction.
D) It has a negative change in free energy.

Question 14

Which of the following is true of energy and living cells?

A) Organisms can create their own energy.
B) Organisms do not require inputs of energy from the environment.
C) Organisms require inputs of energy from the environment to survive.
D) Only heterotrophic organisms require environmental energy inputs to survive.

Question 15

Humans harness microbial ________ to preserve foods and retain caloric value.

A) glycolysis
B) fermentation
C) TCA cycle
D) aerobic respiration

Question 16

Which numbered arrow(s)point(s)to a step that indicates reactions carried out by heterotrophs?

A) 1
B) 2
C) 3
D) 1 and 2

Question 17

A metabolic reaction can only provide energy to cells if

A) DG is negative.
B) DG is positive.
C) DS is negative.
D) DS is positive.

Question 18

Starting with one glucose molecule,the products of glycolysis include

A) 1 pyruvate, 2 net ATP, and 2 NADPH.
B) 1 pyruvate, 4 net ATP, and 2 NADH.
C) 2 pyruvate, 4 net ATP, and 4 NADH.
D) 2 pyruvate, 2 net ATP, and 2 NADH.

Question 19

Which reactions both require energy?

A) ATP hydrolysis and reduction of NAD+
B) ATP hydrolysis and oxidation of NADH
C) ATP production and reduction of NAD+
D) ATP production and oxidation of NADH

Question 20

Enzymes increase reaction rates by

A) increasing activation energies.
B) decreasing activation energies.
C) increasing the concentration of reactants.
D) increasing the concentration of products.

Question 21

If in the ETS electrons are passed from a to b and finally accepted by c, then
A) a is a stronger electron acceptor than b.
B) a is a stronger electron acceptor than c.
C) a is a stronger electron donor than b.
D) c is a stronger electron donor than b.

A) a is a stronger electron acceptor than
B)
B)
B)

Question 22

Under what environmental conditions might bacteria produce ATP more readily?

A) slightly acidic environment
B) slightly basic environment
C) greatly elevated temperature
D) greatly decreased temperature

Question 23

Which of the following is a benefit to humans of the Calvin cycle?

A) It releases oxygen into the atmosphere, which humans require for aerobic respiration.
B) It creates biomass, which is the basis for food chains.
C) It synthesizes antibiotics that can help combat emerging pathogens.
D) It reduces nitrogen, eliminating the need for expensive fertilizers.

Question 24

Which of the following is NOT powered by the proton motive force in bacteria?

A) ATP synthase
B) DNA replication
C) drug efflux
D) flagella rotation

Question 25

Which of the following plants can grow without fertilizer?

A) plants with rhizobia symbionts
B) plants that do not need proteins
C) plants that do not need nucleic acids
D) plants that can carry out the Calvin cycle

Question 26

Oxidative phosphorylation requires

A) ATP synthase.
B) carbon dioxide.
C) NAD+.
D) pyruvate dehydrogenase.

Question 27

What metabolic strategy is summarized in this equation: C₆H₁₂O₆ + 6H₂O + 6O₂ →12H₂O + 6CO₂

A) oxygenic photosynthesis
B) aerobic lithotrophy
C) anaerobic organotrophy
D) aerobic organotrophy

Question 28

Nitrate contamination of water can poison infants.One source of nitrate is

A) lithotrophs that use ammonia as an electron donor.
B) anaerobes that use nitrate as a terminal electron acceptor.
C) methanogens that oxidize H₂ .
D) oxygenic photosynthesis.

Question 29

In the phenol broth red test (shown),a yellow color and bubble (as shown in the far left vial)indicate

Question 30

Which of the following is true of nitrogen fixation?

A) It requires ATP but not reducing agents.
B) It requires reducing agents but not ATP.
C) It is an important reaction carried out by organisms in all three domains of life.
D) Only prokaryotes have the metabolic capability to fix nitrogen.

Question 31

Which of the pathways below are in the correct order for the flow of electrons from glucose to oxygen in aerobic respiration?

A) glycolysis, ETS, TCA
B) glycolysis, fermentation, TCA
C) TCA, glycolysis, ETS
D) glycolysis, TCA, ETS

Question 32

At the end of the TCA cycle most of the energy originally present in glucose is now found in

A) CO₂.
B) NADH.
C) NADPH.
D) ATP.

Question 33

The enzyme Rubisco is involved in

A) ATP production.
B) carbon fixation.
C) fermentation.
D) nitrogen fixation.

Question 34

Photosynthesis helps mitigate global warming by

A) adding O₂ to the atmosphere.
B) removing O₂ from the atmosphere.
C) removing CO₂ from the atmosphere.
D) adding CO₂ to the atmosphere.

Question 35

Why does respiration yield more energy per glucose than fermentation?

A) Fermentation uses more enzymes, and enzymes are costly to make.
B) Fermentation requires oxygen.
C) In fermentation the carbons in glucose do not become fully oxidized.
D) Fermentation is only found in prokaryotic organisms; eukaryotes need more energy.

Question 36

Which molecule is used as a reducing agent in biosynthetic reactions?

A) ATP
B) NADH
C) NADPH
D) glucose

Question 37

During photosynthesis,ATP is produced via

A) oxidation of glucose.
B) transfer of a phosphate from NADPH onto ADP.
C) ATP synthase powered by a pmf.
D) ATP synthase powered directly by light.

Question 38

A bacterium that lacks a respiratory chain likely relies on what metabolic strategy for energy production?

A) aerobic lithotrophy
B) anaerobic lithotrophy
C) photosynthesis
D) glycolysis followed by fermentation

Question 39

Oxygenic photosynthesis strips electrons from

A) CO₂.
B) H₂O.
C) H₂ S.
D) O₂.

Question 40

A bacterial electron transport system (ETS)is depicted.If the quinone pool were artificially depleted,what are the expected consequences?

A) a buildup of NADH and increased H₂O production
B) a buildup of NADH and decreased H₂O production
C) a buildup of NAD+ and increased H₂O production
D) a buildup of NAD+ and decreased H₂O production

Question 41

CASE HISTORY
Tonya,age 32,was spending a warm June weekend at a beach in Massachusetts.The water near shore looked clear,although farther offshore the water had a reddish tint.Tonya dug up a pailful of clams and cooked them thoroughly.After dinner,her lips grew numb and her fingers tingled.She felt nauseated and had difficulty walking across the room.Her speech became slurred,but she managed to dial 911.The ambulance got her to the hospital in time for Tonya to have her stomach pumped and receive assistance breathing.The physician explained to Tonya that she had contracted paralytic shellfish poisoning from consumption of clams contaminated by an algal toxin.The toxin,called saxitoxin,accumulates in the clams as they feed on the algae;cooking does not affect the toxin.At that time,Massachusetts had a ban on shellfish because of a high population density of saxitoxin-producing algae,Alexandrium tamarense,a cause of "red tide."
Though Tonya suffered from consumption of saxitoxin,the organisms that produced it are valuable to humans as well.Explain how these myxotrophic organisms produce a product necessary to our respiration.

Question 42

The Embden-Myerhof-Parnas (EMP)pathway is also known as ________.

Question 43

Compare and contrast anaerobic respiration and fermentation.How are they similar and how do they differ?

Question 44

Lithotrophs donate electrons from inorganic reduced molecules directly to an ETS to generate a proton motive force.Why might these lithotrophs still possess the tricarboxylic acid cycle?

Question 45

The ultimate goal of the Calvin cycle is to produce ________.

Question 46

Yeast ferment hexose sugars into two molecules of ethanol and two molecules of CO₂.This reaction is used in bread making-the CO₂ causes the dough to rise.Explain why this reaction is so sensitive to temperature,slowing down considerably at lower temperatures.

Question 47

Compare and contrast ATP production in chloroplasts and mitochondria.How are they similar and how do they differ?

Question 48

Why does sugar production from CO₂ require NADPH in addition to ATP? In other words,why is ATP not sufficient?

Question 49

CASE HISTORY
Shane,a 21-year-old college student,was spending spring break at the beach in Cancun,where he frequently ordered drinks from the beachfront stands.Upon his return to classes,Shane fell ill with a fever of 38.9°C (102°F),severe abdominal cramps,and watery diarrhea.
By the second day,Shane had blood in his stools,a condition known as dysentery.Upon admission to the hospital,Shane showed dehydration,and his rectal exam was very painful with bleeding.
A fecal culture was performed on Hektoen agar,a selective medium for Gram-negative bacteria;bile salts exclude Gram-positives.Hektoen agar also differentiates among the enteric Gram-negative pathogens Salmonella,Shigella,and Escherichia.Most Salmonella species show black colonies due to H₂S formation from thiosulfate,whereas Escherichia species form colonies that are orange from lactose fermentation.Shane's culture produced translucent colonies,indicating Shigella species,which neither ferment lactose nor reduce thiosulfate to H₂S.
Serotyping (determining which antibodies react with the pathogen)confirmed the species Shigella flexneri,a common cause of "traveler's diarrhea" from drinking contaminated water.Shane received intravenous rehydration and was given the antibiotic quinolone,chosen based on laboratory tests of the pathogen's antibiotic sensitivity.Afterward,Shane made a full recovery.
On Hektoen agar,Salmonella colonies appear black,whereas Escherichia species form colonies that are orange.This helps microbiologists identify the organisms,and is actually representative of

A) differences in the enzymes produced by different species, which normally allow them to utilize nutrients in their environments.
B) differences in the color of the cells themselves.
C) how quickly the organisms are able to grow on this medium and how quickly they take up dyes.
D) the virulence or pathogenicity of the organisms (whether they can infect humans).

Question 50

If Fe³⁺ is the final electron acceptor at the end of an electron transport system,the waste product is ________.

Question 51

The metabolic pathway used by cyanobacteria and plants to fix carbon dioxide into sugar is known as the ________ cycle.

Question 52

CASE HISTORY
Brianna was a 2-month-old,formula-fed infant in a rural community in Nebraska.Brianna's mother noticed signs of blueness around the baby's mouth and fingers.One night after feeding,Brianna had trouble breathing,and her face had a peculiar lavender color.The infant became lethargic,salivated excessively,and had diarrhea and vomiting.An EMT came and took blood samples,which appeared brown and failed to turn pink when exposed to air.The EMT diagnosed methemoglobinemia,a condition in which toxic levels of nitrite oxidize hemoglobin and prevent it from receiving oxygen.The nitriteoxidized hemoglobin is called methemoglobin;elevated levels can cause asphyxiation and death.A solution of methylene blue,a reducing agent,was administered by IV to reduce (add electrons to)the hemoglobin in Brianna's blood.
Nitrite forms in the digestive tract by bacterial reduction of nitrate during anaerobic respiration.The well water from which Brianna's formula was prepared was tested and found to contain high levels of nitrate,enough to cause methemoglobinemia.Brianna's parents were surprised because they had felt no ill effect from the water.But an infant's stomach pH is high,allowing bacteria to reduce nitrate to nitrite,which may then oxidize hemoglobin.
The nitrite in the baby's blood was formed by her intestinal bacteria using nitrate (NO3⁻)as a terminal electron acceptor for anaerobic respiration,with nitrite (NO₂⁻)as the product.Bacteria can multiply more quickly by utilizing oxygen as a terminal electron acceptor in which process?

A) fermentation
B) the pentose phosphate pathway
C) aerobic respiration
D) lithotrophy

Question 53

Biosynthetic reactions are also known as ________ reactions.