Chpt 5 Used And Forms Of Energy Derived From Metabolism

Question 1

1. Energy is defined as a) The ability to do work b) The rate of doing work c) The force applied over a distance d) The change in momentum of an object

Answer 1

Answer: a) The ability to do work Explanation: This definition is directly stated at the beginning of the excerpt.

Question 2

2. Which of the following is NOT a form of energy commonly used by animal and plant cells in respiration? a) Sugars b) Amino acids c) Fatty acids d) Nucleic acids

Answer 2

Answer: d) Nucleic acidsExplanation: The excerpt specifically mentions sugars amino acids and fatty acids as being commonly used in respiration. Nucleic acids are not included in this list.

Question 3

3. What is bioenergetics? a) The study of the structure of biological molecules b) The study of energy changes in living systems c) The study of the evolution of energy metabolism d) The study of the uses of energy in industrial processes

Answer 3

Answer: b) The study of energy changes in living systems Explanation: This is the direct definition provided in the excerpt for bioenergetics.

Question 4

4. A closed system in thermodynamics: a) Exchanges both matter and energy with its surroundings b) Exchanges matter but not energy with its surroundings c) Exchanges energy but not matter with its surroundings d) Exchanges neither matter nor energy with its surroundings

Answer 4

Answer: c) Exchanges energy but not matter with its surroundings Explanation: The excerpt defines a closed system as one that can exchange energy but not matter.

Question 5

5. The first law of thermodynamics states that energy can neither be: a) Created nor destroyed b) Transformed nor transferred c) Absorbed nor emitted d) Potential nor kinetic

Answer 5

Answer: a) Created nor destroyed Explanation: This is a fundamental concept in thermodynamics as stated in the excerpt.

Question 6

6. In the equation ΔE = Q - W what does “W” represent? a) Internal energy of the system b) Heat absorbed by the system c) Work done by the system d) Change in enthalpy of the system

Answer 6

Answer: c) Work done by the system Explanation: The excerpt provides the equation for the first law of thermodynamics and defines each variable including “W” as work done by the system.

Question 7

7. Enthalpy (H) is a function of state that is closely related to: a) Entropy b) Free energy c) Heat content d) Temperature

Answer 7

Answer: c) Heat content Explanation: The excerpt describes enthalpy as a function of state primarily related to the heat content of a system.

Question 8

8. The volume change (ΔV) in biochemical reactions is usually: a) Large b) Significant c) Small d) Unpredictable

Answer 8

Answer: c) SmallExplanation: The excerpt states that volume change is usually small in biochemical reactions making enthalpy a useful approximation for energy change.

Question 9

9. The second law of thermodynamics indicates that the universe always tends towards: a) Lower energy states b) More order c) More disorder d) Equilibrium

Answer 9

Answer: c) More disorder Explanation: This is a key takeaway from the second law of thermodynamics which is focused on the concept of entropy and increasing disorder.

Question 10

10. For a spontaneous process the total entropy of a system and its surroundings: a) Decreases b) Remains constant c) Increases d) Becomes zero

Answer 10

Answer: c) Increases Explanation: This aligns with the second law of thermodynamics where spontaneous processes lead to an overall increase in the entropy of the universe.

Question 11

11. Equilibrium in a system is reached when: a) Entropy is at a minimum b) Entropy is at a maximum c) Free energy is at a minimum d) Free energy is at a maximum

Answer 11

Answer: b) Entropy is at a maximum Explanation: The excerpt explains that equilibrium corresponds to a state of maximum entropy or disorder in a system.

Question 12

12. Free energy (G) combines the two laws of thermodynamics and is a function of: a) Temperature and volume b) Enthalpy and entropy c) Pressure and volume d) Internal energy and work

Answer 12

Answer: b) Enthalpy and entropy Explanation: The excerpt introduces free energy as a thermodynamic function combining enthalpy and entropy reflecting both energy content and disorder.

Answer 13

13. A negative ΔG value for a reaction indicates: a) The reaction is non-spontaneous b) The reaction is spontaneous c) The reaction is at equilibrium d) The reaction requires energy input Answer: b) The reaction is spontaneous Explanation: A key concept in thermodynamics as explained in the excerpt is that a negative change in free energy signifies a spontaneous reaction one that will proceed without external energy input.

Question 14

14. If ΔG for a reaction is zero: a) The reaction is highly spontaneous b) The reaction will not occur c) The reaction is at equilibrium d) The reaction requires a catalyst

Answer 14

Answer: c) The reaction is at equilibrium Explanation: As discussed in the excerpt a free energy change of zero is a defining characteristic of a system at equilibrium where the forward and reverse reaction rates are balanced.

Question 15

15. The rate of a reaction is: a) Directly proportional to ΔG b) Inversely proportional to ΔG c) Unrelated to ΔG d) Dependent on the sign of ΔG

Answer 15

Answer: c) Unrelated to ΔG Explanation: This highlights a crucial distinction free energy dictates the spontaneity of a reaction but not its speed. Reaction rates are governed by activation energies.

Question 16

16. According to the first law of thermodynamics: a) Entropy always increases b) Energy cannot be created or destroyed c) All reactions are spontaneous d) Work can be converted to heat but heat cannot be converted to work

Answer 16

Answer: b) Energy cannot be created or destroyed Explanation: This reiterates the fundamental principle of energy conservation as per the first law of thermodynamics.

Question 17

17. A reversible process: a) Proceeds with minimum energy loss b) Proceeds with maximum energy loss c) Occurs only in closed systems d) Cannot reach equilibrium

Answer 17

Answer: a) Proceeds with minimum energy loss Explanation: The excerpt links reversible processes with maximum efficiency implying minimal energy dissipation.

Question 18

18. The change in free energy (ΔG) for a chemical reaction is related to a) The enthalpy change only b) The entropy change only c) The equilibrium constant d) The activation energy

Answer 18

Answer: c) The equilibrium constant Explanation: The excerpt establishes a connection between the free energy change of a reaction and its equilibrium constant a crucial concept in understanding reaction dynamics.

Question 19

19. The expression Keq = [C][D]/[A][B] represents a) The rate constant of a reaction b) The equilibrium constant for a reaction c) The enthalpy change of a reaction d) The entropy change of a reaction

Answer 19

Answer: b) The equilibrium constant for a reaction Explanation: This expression defines the equilibrium constant (Keq) in terms of product and reactant concentrations a fundamental equation in chemical equilibrium.

Question 20

20. Standard free energy change (ΔG°) is calculated when a) The reactants and products are at 1M concentration b) The temperature is 0°C c) The pressure is 1 atm d) The reaction is at equilibrium

Answer 20

Answer: a) The reactants and products are at 1M concentration Explanation: The standard free energy change is defined under specific conditions including a 1M concentration for reactants and products.

Question 21

21. At equilibrium ΔG = a) -RTlnKeq b) RTlnKeq c) 0 d) ΔG°

Answer 21

Answer: c)Explanation: A key principle in thermodynamics is that at equilibrium the free energy change of a reaction is zero indicating a balance between the forward and reverse processes.

Question 22

22. If Keq is less than 1 the reaction is a) Endergonic b) Exergonic c) Spontaneous d) At equilibrium

Answer 22

Answer: a) Endergonic Explanation: The excerpt explains that a Keq value less than 1 corresponds to a positive standard free energy change making the reaction endergonic meaning it requires energy input to proceed.

Question 23

23. If ΔG is negative the reaction is a) Endergonic b) Exergonic c) Non-spontaneous d) At equilibrium

Answer 23

Answer: b) ExergonicExplanation: As discussed in the excerpt a negative free energy change is a defining characteristic of an exergonic reaction indicating that it releases energy and proceeds spontaneously.

Question 24

24. Adenosine triphosphate (ATP) is a) A storage form of glucose b) The molecular currency of energy in the cell c) An enzyme that catalyzes energy transfer d) A structural component of the cell membrane

Answer 24

Answer: b) The molecular currency of energy in the cellExplanation: This metaphor is widely used to emphasize ATP’s central role in cellular energy transactions.

Question 25

25. The energy of ATP is stored in a) The adenine base b) The ribose sugar c) The bonds between its terminal phosphate groups d) The interactions with water molecules

Answer 25

Answer: c) The bonds between its terminal phosphate groups Explanation: The excerpt specifically locates the stored energy of ATP within the bonds connecting its terminal phosphate groups.

Question 26

26. The covalent bonds joining the phosphate groups in ATP are a) Stable b) Unstable c) Non-polar d) Hydrophobic

Answer 26

Answer: b) Unstable Explanation: The excerpt describes the bonds between phosphate groups in ATP as unstable due to repulsion from negative charges highlighting their propensity to break and release energy.

Question 27

27. Hydrolysis of ATP is a) An endergonic reaction b) An exergonic reaction c) A reaction that requires energy input d) A reaction that does not involve energy changes

Answer 27

Answer: b) An exergonic reaction Explanation: ATP hydrolysis is a fundamental energy-releasing process in cells as indicated by its exergonic nature.

Question 28

28. ATP hydrolysis is coupled to a) Exergonic reactions b) Endergonic reactions c) Reactions with large negative ΔG d) Reactions at equilibrium

Answer 28

Answer: b) Endergonic reactions Explanation: The excerpt describes the critical role of ATP hydrolysis in driving otherwise non-spontaneous endergonic reactions by providing the necessary energy.

Question 29

29. The energy released from ATP hydrolysis can be used to a) Drive endergonic reactions b) Synthesize ATP c) Both a and b d) None of the above

Answer 29

Answer: c) Both a and bExplanation: This highlights the cyclical nature of ATP as an energy carrier being broken down to power cellular processes and then resynthesized using energy from other sources.

Question 30

30. ATP is synthesized with energy from a) Photosynthesis b) Respiration c) Both a and b d) None of the above

Answer 30

Answer: c) Both a and b Explanation: While not directly stated in the excerpt it is a fundamental biological concept that ATP synthesis is powered by both photosynthesis in plants and respiration in most organisms.

Question 31

31. Define energy as it relates to biological systems

Answer 31

Answer: Energy is the capacity to do work in a biological context. This work can manifest as mechanical movement heat production bioluminescence and various other cellular processes.

Question 32

32. State the first law of thermodynamics

Answer 32

Answer: The first law of thermodynamics posits that energy can neither be created nor destroyed but can be transformed from one form to another.

Question 33

33. What is the significance of ΔG (Gibbs Free Energy) in predicting the spontaneity of a reaction

Answer 33

Answer: The sign of ΔG indicates whether a reaction will proceed spontaneously. A negative ΔG denotes a spontaneous reaction while a positive ΔG indicates a non-spontaneous reaction.

Question 34

34. Explain the relationship between entropy and the second law of thermodynamics

Answer 34

Answer: The second law of thermodynamics states that the total entropy of a system and its surroundings always increases for spontaneous processes. Entropy is a measure of disorder so this law essentially describes the tendency towards increased randomness in the universe.

Question 35

35. How does ATP function as the “energy currency” of the cell

Answer 35

Answer: ATP serves as the primary energy carrier in cells. Its high-energy phosphate bonds can be broken through hydrolysis releasing energy that drives various cellular processes. This energy can then be used to resynthesize ATP from ADP creating a cycle of energy storage and utilization.