Question 1

Which of the following best describes the difference between potential and kinetic energy in the context of a skier on a hill?

Accepted Answer

Potential energy is the stored energy when the skier is at the top of the hill, and kinetic energy is the energy of motion as the skier coasts downhill.

Question 2

In biological systems, which of the following is an example of potential energy?

Accepted Answer

The energy stored in the chemical bonds of glucose.

Question 3

Which equation correctly represents the relationship between free energy ($$\Delta G$$), enthalpy ($$\Delta H$$), entropy ($$\Delta S$$), and temperature ($$T) in a $$chemical reaction?

Accepted Answer

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

Question 4

A reaction is considered spontaneous if:

Accepted Answer

The products have lower potential energy and higher entropy than the reactants.

Question 5

Which of the following statements about the First Law of Thermodynamics is correct?

Accepted Answer

Energy can be converted from one form to another, but cannot be created or destroyed.

Question 6

Why are energy transformations in biological systems never completely efficient?

Accepted Answer

Because some energy is always lost as heat, increasing the entropy of the system or environment.

Question 7

Which of the following best explains why a reaction with a negative $$\Delta G is $$considered exergonic?

Accepted Answer

It releases energy that can be used to do work.

Question 8

Which of the following is a real-life example of energetic coupling in cells?

Accepted Answer

The use of ATP hydrolysis to drive the active transport of ions against their concentration gradient.

Question 9

What is the primary role of enzymes in biological reactions?

Accepted Answer

To lower the activation energy required for the reaction to proceed.

Question 10

A patient is found to have a deficiency in a dietary mineral that acts as a cofactor for an important metabolic enzyme. What is the most likely consequence?

Accepted Answer

The enzyme's activity will decrease because it cannot achieve its proper shape or function without the cofactor.

Question 11

Which of the following best describes feedback inhibition in a metabolic pathway?

Accepted Answer

The final product of the pathway inhibits an early enzyme, preventing overproduction.

Question 12

If the temperature of an enzyme-catalyzed reaction is increased beyond the enzyme's optimal range, what is the most likely outcome?

Accepted Answer

The enzyme will denature, causing the reaction rate to decrease.

Question 13

Which of the following scenarios illustrates competitive inhibition of an enzyme?

Accepted Answer

A molecule similar in structure to the substrate binds to the active site, blocking substrate binding.

Question 14

Which of the following best explains why increasing substrate concentration does not always lead to a proportional increase in enzyme-catalyzed reaction rate?

Accepted Answer

All active sites become saturated, so the reaction rate reaches a maximum.

Question 15

Which of the following is an example of an allosteric regulator of an enzyme?

Accepted Answer

A molecule that binds to a site other than the active site, causing a conformational change that affects enzyme activity.

Question 16

A reaction has a positive $$\Delta G. $$Which of the following statements is true?

Accepted Answer

The reaction is endergonic and requires an input of energy to proceed.

Question 17

Which of the following best describes the role of phosphorylation in enzyme regulation?

Accepted Answer

Phosphorylation changes the shape and function of the enzyme, activating or inactivating it.

Question 18

Which of the following would most likely increase the rate of a non-catalyzed chemical reaction in a cell?

Accepted Answer

Increasing the temperature and reactant concentration.

Question 19

Which of the following is a correct statement about activation energy ($$E_a) in $$chemical reactions?

Accepted Answer

Activation energy is the minimum amount of energy required to break bonds and form a transition state.

Energy and Thermodynamics in Biology: Structured Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard