Microbial Metabolism [1]

Question 1

A defined culture medium must supply all of the nutrients an organism needs, including essential biochemicals that the cell cannot synthesize. Based on the following recipe, this defined medium could support the growth of certain members of what group? Recipe: 7 g of K2HPO4; 2 g of KH2PO4; 1g of (NH4)2SO4; 0.1g of MgSO4; 0.02g of CaCl2; 10g of glucose; trace elements mix; 1000mL of distilled water; adjust to pH 7.
A nitrogen-fixer
B autotroph
C chemolithotroph
D chemoorganotroph

Answer 1

D

Question 2

Which of the following would be used by a chemoorganotroph for energy?
A C2H3O2-
B CO2
C H+
D H2

Answer 2

A

Question 3

A chemoorganotroph and a chemolithotroph in the same environment would NOT compete for
A phosphorous.
B carbon.
C oxygen.
D nitrogen.

Answer 3

B

Question 4

A chemoorganotroph and a photoautotroph in the same environment would NOT compete for
A nitrogen.
B carbon and oxygen.
C oxygen.
D carbon.

Answer 4

B

Question 5

For a carbon source, chemoorganotrophs generally use compounds such as
A nitrate and nitrite.
B acetate, bicarbonate, and nitrate.
C acetate, succinate, and glucose.
 bicarbonate and carbon dioxide.

Answer 5

C

Question 6

Which statement below demonstrates why the majority of organisms are heterotrophs?
A The majority of organisms obtain their carbon from inorganic sources.
B The majority of organisms conserve energy from inorganic sources and their carbon from organic sources.
C The majority of organisms conserve energy from inorganic sources.
D The majority of organisms obtain their carbon from organic sources.

Answer 6

D

Question 7

The reactions involved in producing larger compounds from smaller compounds is called
A anabolism.
B metabolism.
C catabolism.

Answer 7

A

Question 8

Where does the energy required for anabolic reactions come from?
A Catabolic reactions
B Unused energy from metabolism
C Heat

Answer 8

A

Question 9

The Pentose Phosphate Pathway
A is an example of catabolism.
B is a part of photosynthesis.
C is an example of anabolism.
D is another name for fermentation.

Answer 9

C

Question 10

According to the animation, oxidative phosphorylation
A requires a net input of energy.
B is a catabolic process.
C makes larger compounds from smaller ones.
D is an anabolic process.

Answer 10

B

Question 11

According to the animation, the reactions that occur between glucose and pyruvic acid
A are only anabolic.
B are only catabolic.
C are neither catabolic nor anabolic.
D can either be anabolic or catabolic.

Answer 11

D

Question 12

To calculate the free energy (ΔG0′) of a reaction, you can subtract the free energies of formation (Gf0) of the reactants from those of the products. Given the following data, what will be true of this reaction? C6H12O6 + O2 → CO2 + H2O Gf0 : -917.3 0 -394.4 -237.2
A The reaction will not require a catalyst to proceed.
B The reaction will be exergonic.
C The reaction is not balanced, so you cannot calculate the change in free energy.
D The reaction will be endergonic.

Answer 12

B

Question 13

The change in Gibbs free energy for a particular reaction is MOST useful in determining
A the potential metabolic reaction rate.
B energy stored in each compound.
C the amount of energy catalysts required for biosynthesis or catabolism.
D whether there will be a requirement or production of energy.

Answer 13

D

Question 14

Free-energy calculations are dependent on the rates of the reactions.
A True
B False

Answer 14

B

Question 15

The role of an enzyme includes all EXCEPT which of the following?
A straining chemical bonds in a substrate so that they break easier
B reducing the rate of a reaction to allow for better control
C binding only one specific substrate to the enzyme active site
D lowering the activation energy of a reaction

Answer 15

B

Question 16

Why do all enzymatic reactions need activation energy?
A Energy is required by an enzyme so that it can be reused.
B Energy is needed for the enzyme to find its substrate.
C Energy is required to disrupt a substrate’s stable electron configuration.
D Energy allows only the substrate to bind.

Answer 16

C

Question 17

What is meant by the statement “Enzymes are biological catalysts”?
A Enzymes produce products useful for biology.
B Enzymes speed up the chemical reactions in living cells.
C Enzymes are products of biological systems.
D Enzymes produce biological organisms.

Answer 17

B

Question 18

Why are enzymes important to biological systems?
A Enzymes prevent unwanted chemical by-products from forming.
B Enzymes increase the energy barrier required of chemical reactions.
C Enzymes decrease the amount of activation energy required for chemical reactions to occur.
D Enzymes are reuseable.

Answer 18

C

Question 19

The reduction potential (E0′) of a substance reflects its tendency to donate or accept electrons. The larger the difference (ΔE0′) between the reduction potentials of the electron donor and the electron acceptor, __________.
A the greater the change in free energy (ΔG0′), and the less energy is released
B the closer the substances are on the electron tower
C the more enzymes will be required to catalyze the reaction(s)
D the greater the change in free energy (ΔG0′), and the greater the energy released

Answer 19

D

Question 20

If an oxidation reaction occurs
A another oxidation reaction will occur for a complete reaction, because one oxidation event is considered a half reaction.
B a reduction reaction would not occur, because they are opposite reaction mechanisms.
C a cell is undergoing aerobic respiration, because oxygen is being used.
D simultaneous reduction of a different compound will also occur, because electrons do not generally exist alone in solution.

Answer 20

D

Question 21

The function of NAD+/NADH in the cell is best described as __________.
A a way to transport protons to the plasma membrane for energy generation in bacteria
B a way to transport electrons to the mitochondria for energy generation in bacteria
C a way to increase the types of redox reactions that occur in the cell by acting as an intermediary between similar compounds
D a way to increase the types of redox reactions that occur in the cell by acting as an intermediary between dissimilar compounds

Answer 21

D

Question 22

If a substance is reduced, it gains electrons.
A True
B False

Answer 22

A

Question 23

A reaction that involves the transfer of electrons from one molecule to another is referred to as
A a reduction reaction.
B an oxidation reaction.
C a redox reaction.

Answer 23

C

Question 24

During an oxidation reaction,
A the donor molecule loses an electron and becomes oxidized.
B the donor molecule gains an electron and becomes oxidized.
C the acceptor molecule loses an electron and becomes oxidized.
D the acceptor molecule gains an electron and becomes oxidized.

Answer 24

A

Question 25

Why is reduction the term used to describe the gain of an electron?
A The electron acceptor gets smaller.
B The electron acceptor’s net charge decreases.
C The number of molecules in the reaction decreases.
D The amount of energy in the molecule decreases.

Answer 25

B

Question 26

Which of the following statements regarding redox reactions is true?
A Redox reactions must either be oxidizing reactions or reducing reactions.
B Redox reactions involve an oxidation reaction coupled with a reduction reaction.
C No metabolic reactions are redox reactions.
D Redox reactions are only seen in the electron transport chain.

Answer 26

B