Question 1

Which of the following best describes a catabolic pathway in cellular metabolism?

Accepted Answer

A pathway that breaks down complex molecules into simpler ones, releasing energy.

Question 2

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

Accepted Answer

Energy can be transferred and transformed, but cannot be created or destroyed.

Question 3

A chemical reaction has a $$\Delta G of$$ $$-50$$ kcal/mol. What does this indicate about the reaction?

Accepted Answer

The reaction is exergonic and will occur spontaneously.

Question 4

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

Accepted Answer

The use of ATP hydrolysis to drive the synthesis of glutamine from glutamic acid and ammonia.

Question 5

What is the main reason why heat is not used by cells to speed up chemical reactions?

Accepted Answer

Heat denatures proteins and speeds up all reactions indiscriminately.

Question 6

Which of the following best explains how enzymes lower the activation energy ($$E_a) of a $$reaction?

Accepted Answer

By providing a site where reactants are brought together in the correct orientation.

Question 7

A metabolic pathway is regulated by feedback inhibition. Which of the following best describes this process?

Accepted Answer

The final product of the pathway inhibits an enzyme that acts early in the pathway.

Question 8

Which of the following is true about ATP hydrolysis?

Accepted Answer

It is an exergonic reaction with $$\Delta G = -7.3$$ kcal/mol.

Question 9

Which of the following bonds are most likely to form between an enzyme and its substrate?

Accepted Answer

Hydrogen, ionic, and sometimes covalent bonds.

Question 10

A scientist measures the $$\Delta G$$ for the following reaction: $$	ext{Glucose} + 6\ O_2$ ightarrow 6\ CO_2$ + 6\ H_2O$$, and finds $$\Delta G = -686$$ kcal/mol. What does this value indicate?

Accepted Answer

The reaction is exergonic and releases energy.

Question 11

Which of the following statements about the regeneration of ATP is correct?

Accepted Answer

It is an anabolic, endergonic process.

Question 12

Which of the following scenarios best illustrates the second law of thermodynamics?

Accepted Answer

During cellular respiration, some energy is lost as heat, increasing the entropy of the surroundings.

Question 13

Which of the following is NOT a way that enzymes lower activation energy?

Accepted Answer

Increasing the $$\Delta G of $$the reaction.

Question 14

A competitive inhibitor of an enzyme works by:

Accepted Answer

Mimicking the substrate and binding to the active site.

Question 15

Which of the following best describes an allosteric inhibitor?

Accepted Answer

It binds to a site other than the active site, stabilizing the enzyme's inactive form.

Question 16

Why do metabolic pathways in living cells rarely reach equilibrium?

Accepted Answer

Because products of one reaction become reactants for the next, and materials flow in and out of the cell.

Question 17

Which of the following is an example of mechanical work in a cell?

Accepted Answer

The movement of a vesicle along a cytoskeletal track by a motor protein.

Question 18

If a reaction has $$\Delta G = 0$$, what does this mean for the reaction in a living cell?

Accepted Answer

The reaction is at equilibrium and cannot do work.

Question 19

Which of the following is a real-life example of feedback inhibition?

Accepted Answer

ATP allosterically inhibits an enzyme involved in ATP-generating pathways.

Question 20

Which of the following best explains why ATP is considered a renewable resource in the cell?

Accepted Answer

ATP is constantly regenerated from ADP and inorganic phosphate using energy from catabolic reactions.

Metabolism and Energy in Biological Systems (Chapter 8 Study Notes)

Guida di studio - Domande di pratica

Study guide - Flashcard