Question 1

Which of the following best describes the difference between kinetic and potential energy in biological systems?

Accepted Answer

Kinetic energy is the energy of motion, such as thermal energy, while potential energy is stored in the position or configuration of molecules, such as chemical energy in bonds.

Question 2

According to the first law of thermodynamics, which of the following statements is correct?

Accepted Answer

Energy cannot be created or destroyed, only transferred or transformed.

Question 3

A chemical reaction has a negative $$\Delta H$$ and a positive $$\Delta S. $$What can you conclude about the spontaneity of this reaction at any temperature?

Accepted Answer

The reaction is spontaneous at all temperatures.

Question 4

Which equation correctly represents the relationship between Gibbs free energy, enthalpy, and entropy?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 5

Which of the following best explains why ATP has a high potential energy?

Accepted Answer

ATP contains three phosphate groups with clustered negative charges that repel each other.

Question 6

During a redox reaction, which of the following statements is true?

Accepted Answer

Oxidation is the loss of electrons and reduction is the gain of electrons; these processes always occur together.

Question 7

Which of the following is an example of energetic coupling in cells?

Accepted Answer

The use of ATP hydrolysis (an exergonic reaction) to drive the synthesis of glutamine from glutamate and ammonia (an endergonic reaction).

Question 8

Which of the following statements about enzyme catalysis is correct?

Accepted Answer

Enzymes lower the activation energy ($$E_a) $$required for a reaction to proceed.

Question 9

A researcher increases the substrate concentration in an enzyme-catalyzed reaction, but the reaction rate eventually plateaus. What is the most likely explanation?

Accepted Answer

All enzyme active sites are occupied, and the reaction has reached saturation.

Question 10

Which of the following best describes competitive inhibition of an enzyme?

Accepted Answer

A molecule binds to the active site, preventing the substrate from binding.

Question 11

Which of the following is a likely effect of increasing temperature above the optimal range for a human enzyme?

Accepted Answer

The enzyme will denature, losing its structure and function.

Question 12

Which of the following statements about feedback inhibition in metabolic pathways is correct?

Accepted Answer

Feedback inhibition occurs when the final product of a pathway inhibits an enzyme earlier in the pathway.

Question 13

Which of the following is NOT a way that enzymes can be regulated?

Accepted Answer

By permanently increasing the activation energy of the reaction.

Question 14

Which of the following best describes the role of NAD+ in cellular metabolism?

Accepted Answer

NAD+ acts as an electron carrier, accepting electrons and a proton to form NADH.

Question 15

A mutation causes an enzyme to lose its ability to bind a required cofactor. What is the most likely result?

Accepted Answer

The enzyme will lose its catalytic activity.

Question 16

Which of the following is true about the transition state in an enzyme-catalyzed reaction?

Accepted Answer

The transition state is an intermediate with the highest free energy along the reaction pathway.

Question 17

Which of the following best explains why metabolic pathways are often regulated by feedback inhibition?

Accepted Answer

To prevent the overaccumulation of the final product and conserve resources.

Question 18

Which of the following statements about anabolic and catabolic pathways is correct?

Accepted Answer

Anabolic pathways use energy to synthesize molecules, while catabolic pathways break down molecules for energy.

Question 19

A scientist is studying an enzyme that is regulated by phosphorylation. Which of the following statements is most accurate?

Accepted Answer

Phosphorylation can either activate or deactivate the enzyme by changing its shape.

Energy and Enzymes: An Introduction to Metabolism (Chapter 8 Study Notes)

Guida di studio - Domande di pratica

Study guide - Flashcard