Question 1

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

Accepted Answer

Potential energy is stored due to the location or structure of molecules, while kinetic energy is the energy of motion.

Question 2

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

Accepted Answer

Energy can be transferred or transformed, but the total amount remains constant.

Question 3

Which of the following scenarios would result in an increase in entropy ($$S) in a $$biological system?

Accepted Answer

Hydrolysis of a polysaccharide into monosaccharides.

Question 4

A chemical reaction has $$\Delta H = -50 kJ/$$mol and $$\Delta S = +0.1 kJ/($$mol\cdot K).$$ At T = 300$ K, what is $$\Delta G$ for this reaction?

Accepted Answer

$$\Delta G = -80 kJ/$$mol

Question 5

Which of the following best explains why ATP stores a large amount of potential energy?

Accepted Answer

ATP has clustered negative charges in its phosphate groups, increasing repulsion and potential energy.

Question 6

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

Accepted Answer

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

Question 7

Which of the following is true about exergonic reactions in cells?

Accepted Answer

They have a negative $$\Delta G$$ and occur spontaneously.

Question 8

The hydrolysis of ATP is often coupled to endergonic reactions in cells. What is the main reason this coupling is effective?

Accepted Answer

The energy released from ATP hydrolysis is transferred to substrates via phosphorylation, making them more reactive.

Question 9

Which of the following best describes the role of catabolic reactions in metabolism?

Accepted Answer

They break down complex molecules into simpler ones, releasing energy.

Question 10

A cell needs to synthesize glutamine from glutamic acid and ammonia, an endergonic process. How does the cell make this reaction spontaneous?

Accepted Answer

By coupling the reaction with ATP hydrolysis, which provides energy and phosphorylates glutamic acid.

Question 11

Which of the following is a correct statement about the second law of thermodynamics as it applies to biological systems?

Accepted Answer

Energy will always become more spread out unless hindered.

Question 12

Which of the following is an example of an anabolic reaction?

Accepted Answer

Synthesis of a protein from amino acids.

Question 13

If a reaction has $$\Delta G = +5 kJ/$$mol, which of the following is true?

Accepted Answer

The reaction is endergonic and requires energy input.

Question 14

Which of the following best explains why the combustion of glucose is spontaneous in cells?

Accepted Answer

The products have lower enthalpy and higher entropy than the reactants.

Question 15

Which of the following is a direct result of phosphorylation of a substrate by ATP?

Accepted Answer

The substrate's free energy increases, making it more reactive.

Question 16

Which of the following statements about metabolism is correct?

Accepted Answer

Catabolic reactions release energy, which is used to power anabolic reactions.

Question 17

Which of the following is NOT a way that entropy ($$S) $$can increase in a system?

Accepted Answer

Decrease in molecular random motion.

Question 18

Which of the following best describes how energy is transferred between catabolic and anabolic reactions in cells?

Accepted Answer

Energy is transferred via small diffusible molecules such as ATP, NADH, or FADH$$_2.$$

Question 19

Which of the following is true about the hydrolysis of ATP?

Accepted Answer

It is an exergonic reaction that releases energy.

Week 4 - Sept 24

Study Guide - Practice Questions