Ch4 – Cellular Metabolism | Test Bank – 18th Ed

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MULTIPLE CHOICE - Choose the one alternative that best completes the statement or answers the question.
1) Cellular ____________ refers to the collective total of chemical processes that occur within living cells.

A) energy
B) thermodynamics
C) potential
D) metabolism

2) Pretend that you are explaining basic thermodynamic principles to your roommate. Which of the following pairs could you use as an example of an INCORRECT pairing?

A) kinetic energy: glucose
B) kinetic energy: muscle movement
C) potential energy: water held behind a dam
D) kinetic energy: a ball rolling down a hill

3) The first law of thermodynamics states that

A) energy is not created nor destroyed, but it can change into matter.
B) energy is not created nor destroyed, but it can change from one energy form to another.
C) energy can be created from matter or used to produce matter.
D) energy transfers are always 100% efficient in changing energy from one useful form to another.

4) The second law of thermodynamics states that

A) energy is not created nor destroyed, but it can change into matter.
B) energy is not created nor destroyed, but it can change from one energy form to another.
C) energy organizes in a closed system and moves toward increasing order.
D) energy dissipates in a closed system and moves toward increasing disorder.

5) According to the laws of physics governing energy

A) when a liter of gasoline is burned in a car engine, 100% of its energy moves the car along the road.
B) when you eat a kilogram of food, you will assemble exactly a kilogram of additional body weight on your body.
C) sunlight that is absorbed on the earth eventually returns to space as dispersed heat.
D) a calorie of sunlight becomes a calorie of plant tissue that, when eaten by an animal, becomes a calorie of heat used in muscle "power."

6) Living organisms contain stored energy in the form of chemical compounds. When organisms die, what happens to this stored energy?

A) All molecules immediately degrade into basic elements.
B) All chemicals immediately lose their high-energy bonds.
C) Cells lose their organization over time and macromolecules break down because there is no longer an input of energy to maintain an organized state.
D) Chemical compounds remain intact and ready to start up again unless digested by a consumer or decomposer.

7) You have been asked to be a tutor for the freshman biology course. An exam is approaching and several students have approached you to get assistance understanding metabolic reactions. Which of the following is an example of an endergonic reaction?

A) are always coupling reactions.
B) occur spontaneously.
C) can only occur if there is an input of energy.
D) are associated with the release of energy.

8) You have been asked to be a tutor for the freshman biology course. An exam is approaching and several students have approached you to get assistance understanding metabolic reactions. Which of the following is an example of an exergonic reaction?

A) are always coupling reactions.
B) can occur spontaneously.
C) can only occur if there is an input of energy.
D) All of the choices are correct.

9) Enzymes

A) lower the amount of energy present in the substrate.
B) raise the amount of energy present in the substrate.
C) lower the energy of activation of a reaction by binding to the substrate.
D) raise the energy of activation of a reaction by binding to the substrate.

10) How do an enzyme and its substrate fit together?

A) The enzyme breaks down as product is released
B) The whole enzyme is a key that fits into the substrate that is a lock forming a new molecule product
C) Any active site is permanently changed when it interacts with the substrate
D) As the substrate binds to the enzyme, the shape of the active site changes to accommodate the reaction

11) Which is true about the activity of an enzyme?

A) Lower temperatures generally increase enzyme activity.
B) Enzymes are altered or destroyed by the reaction.
C) Enzymes are not products of the reactions they catalyze.
D) Rates of reactions are independent of substrate concentration.

12) If there are ten different intermediate products produced in stages leading to a molecule in a cell, we can expect that there

A) is one enzyme that carries this process through each of the ten stages to the end product.
B) is one enzyme for degradation and another enzyme for synthesis.
C) may not be any enzymes involved if this is a natural cell product.
D) are about ten enzymes, at least one responsible for each step in the metabolic pathway.

13) A coenzyme is

A) an ionic cofactor that interacts with an enzyme to inhibit it.
B) a protein cofactor that interacts with an enzyme to inhibit it.
C) an ionic cofactor that interacts with an enzyme to allow it to work.
D) a protein cofactor that interacts with an enzyme to allow it to work.
E) a nonprotein organic cofactor that interacts with an enzyme to allow it to work.

14) Which of the following is a coenzyme?

A) ATP
B) potential energy
C) FAD
D) kinetic energy

15) The enzyme-substrate complex is

A) not strong and will freely dissociate after it stresses certain chemical bonds in a substrate.
B) secured by covalent bonds to one or more points in the active site of the enzyme.
C) able to display unique spectroscopic characteristics not seen by either the enzyme or thesubstrate alone.
D) proved by the saturation effect in which the reaction rate reaches a maximum even through more substrate is added.
E) All of the choices are correct.

16) How specific are enzymes?

A) Many enzymes can "cross over" to catalyze reactions of different substrates in the same chemical family
B) There are 20 amino acids and therefore 20 enzymes that control all protein metabolic reactions
C) An enzyme catalyzes one reaction but it may produce one product one time, another product another time
D) An enzyme catalyzes one reaction and it produces a distinct product

17) Which is true of enzyme-catalyzed reactions?

A) All enzymes promote only catabolic reactions.
B) Reactions catalyzed by most enzymes tend to go predominantly in one direction.
C) All enzymatic reactions are reversible and produce equal amounts of products in both directions.
D) All enzymes promote only anabolic reactions.

18) The net direction of any chemical reaction depends on the

A) relative energy contents of the substances involved.
B) amount of enzyme present.
C) amount of substrate present.
D) amount of ATP present.

19) When an energy-requiring reaction is driven by an energy-yielding reaction, it is called a/an

A) exergonic reaction.
B) endergonic reaction.
C) endo-exergonic reaction.
D) coupled reaction.

20) Coupling occurs when energy released by an exergonic reaction is

A) used to drive another exergonic reaction.
B) used to drive an endergonic reaction.
C) lost as nonusable heat to the environment.
D) used to decrease the entropy of the universe.

21) The subunits from which ATP is made are

A) ADP and inorganic phosphate.
B) FAD and NAD +.
C) FAD and NADPH.
D) ADP and FAD.

22) ATP is

A) an enzyme used widely in all kinds of cells.
B) a driver of both sides of the coupled reaction that forms ADP.
C) a molecule that carries a great deal of chemical energy in the bond between the terminal two phosphates.
D) the building block of all other cell structures.

23) Which organelle contains ATP synthetase complexes in its membrane?

A) golgi complexes
B) mitochondria
C) vesicles
D) endoplasmic reticulum

24) The most accurate portrayal of ATP is that

A) ATP is a fuel.
B) ATP is a storehouse of energy set aside for some future need.
C) ATP is an energy-coupling agent and is formed and used asneeded.
D) ATP is produced and consumed by the same reaction.

25) What establishes an electrochemical gradient across a membrane to provide energy for ATP production?

A) The mitochondrion's electron transport system provides the ions.
B) Hydrogen ions naturally collect on the outside of the organelle membrane.
C) Hydrogen ions are pumped across the membrane by carrier proteins.
D) All of the choices establish the electrochemical gradient.

26) Which is the true statement about oxidation-reduction reactions?

A) Reduction is the loss of electrons.
B) Reduction is the loss of hydrogen atoms.
C) Oxidation is the loss of electrons and reduction is theaddition of electrons.
D) Reduction and oxidation sometimes occur together, but not always.

27) Which process occurs in the cytoplasm outside the mitochondria?

A) Krebs cycle
B) glycolysis
C) electron transport system
D) substrate level phosphorylation

28) Glycolysis produces a net yield of ____ ATP molecules.

A) 2
B) 4
C) 8
D) 10

29) The first process in breaking down glucose is

A) the Krebs cycle.
B) glycolysis.
C) the electron transport system.
D) fermentation.

30) Following glycolysis, the two molecules of pyruvic acid enter a mitochondrion where each molecule is oxidized to produce

A) glucose.
B) acetyl CoA and carbon dioxide.
C) acetyl CoA and water.
D) pyruvates and carbon dioxide.

31) Both NADH and FADH 2 are produced by

A) the Krebs cycle.
B) glycolysis.
C) the electron transport system.
D) oxidative phosphorylation.

32) Full oxidative breakdown of glucose results in a net of ______ ATP molecules.

A) 2
B) 4
C) 16
D) 36

33) Each turn of the Krebs cycle produces

A) 2 NADH, 2 FADH 2, 2 ATP.
B) 3 NADH, 1 FADH 2, 1 ATP.
C) 1 NADH, 3 FADH 2, 2 ATP.
D) 3 NADH, 2 FADH 2, 1 ATP.

34) Some desert mammals and beetles can live their life without ever drinking liquid water; they survive on "metabolic water." Which is the most likely source of "metabolic water?"

A) is absorbed from the air along with respiratory oxygen
B) results from oxidative phosphorylation inside the mitochondria
C) is a breakdown product from glycolysis in the cytoplasm
D) is water that was never allowed to pass out the cell

35) Which of the following metabolic pathways can be used as a partial answer to the question, 'why do animals need to exhale?'

A) glycolysis
B) the electron transport system
C) lactate fermentation
D) the Krebs cycle

36) Which process involves chemiosmotic coupling?

A) the Krebs cycle
B) glycolysis
C) the electron transport system
D) fermentation

37) Which pairs of processes are anaerobic?

A) glycolysis and the electron transport system
B) fermentation and the Krebs cycle
C) glycolysis and the Krebs cycle
D) fermentation and glycolysis

38) The critical factor that drives many microorganisms to use fermentation to metabolize sugar is

A) inability to carry on glycolysis.
B) lack of free oxygen.
C) lack of any enzymes.
D) intolerance to alcohol.

39) When animals use anaerobic fermentation, which process must occur first?

A) the Krebs cycle
B) glycolysis
C) the electron transport system
D) fermentation

40) In high levels, alcohol is toxic. Why would a creature utilize fermentation if it were wasteful of the energy in food molecules and posed the threat of killing itself?

A) The organism can survive short spells of anaerobic conditions and maintain growth and reproduction.
B) If glucose levels are not high, there may be time to disperse the alcohol "waste".
C) Fermentation can provide a rapid burst of ATP since it does not have to go through the full breakdown cycle.
D) All of the choices are advantages.

41) Which process produces alcohol or lactate?

A) the Krebs cycle
B) glycolysis
C) the electron transport system
D) fermentation
E) oxidative phosphorylation

42) For fatty acids to be able to enter the pathways of cellular respiration, they must be

A) deaminated.
B) combined with glycerol.
C) combined with ATP.
D) broken into 2-carbon units to form acetyl coenzyme A.

43) Because there is a constant need for amino acids to synthesize proteins, it is important to maintain ________ in the ________.

A) the Krebs cycle; mitochondria
B) glycolysis; cytoplasm
C) the electron transport system; mitochondria
D) an amino acid pool; blood

44) Based on what you know about carbohydrate, lipid and protein metabolism which animal diet is most similar to the 'keto diet' that some humans utilize for weight loss?

A) carnivore
B) herbivore
C) omnivore
D) detritovore

FILL IN THE BLANK. Write the word or phrase that best completes each statement or answers the question.
45) Stored energy that is not doing work but has the capacity to do work is called __________ ___________.

46) Before a chemical bond is stressed enough to break, ___________ must be supplied.

47) For some enzymes to function, small nonprotein groups called ________ must participate along with the enzyme molecule.

48) Aerobic organisms use _______ as the final electron acceptor in cellular respiration.

49) Aerobic metabolism requires oxygen consumption and the ultimate source of this free oxygen is generated by autotrophic organisms by the process of _______.

50) Glycolysis involves the conversion of 6-carbon glucose into 3-carbon fragments of ________ ________.

51) In the absence of oxygen, glycolysis and fermentation result in glucose being degraded into two 3-carbon molecules of ______ _______.

ESSAY. Write your answer in the space provided or on a separate sheet of paper.
52) If the second law of thermodynamics states that a closed system moves toward increasing disorder, then how can a living system not only maintain organization but also increase it?

53) When exergonic and endergonic reactions are coupled, which reaction involves more energy and why are the reaction energies not exactly the same?

54) If anaerobic glycolysis is only one-eighteenth as efficient as complete oxidation of glucose to carbon dioxide, then why would an organism use such an inefficient pathway?

55) Why do some animals degrade amino acids to ammonia and others dispose of them as urea or uric acid?

56) Can virtually any organic compound be broken down (assuming it is nontoxic)?

57) Outline a hypothetical scenario of the evolution of metabolism.

58) Discuss research that claims that food intake, and therefore the amount of fat deposition, is creating a "set point" in specific parts of the brain.

59) Research on lipid metabolism has resulted in pharmaceutical drugs that could help fight the obesity epidemic. Explain how these drugs might help someone lose weight.

60) Generate a hypothesis about the regulation of enzymes that control glucose use/storage and breakdown from storage.