Question 1

Which of the following best describes an endergonic reaction in biological systems?

Accepted Answer

A reaction that requires energy input and results in products with more energy than reactants.

Question 2

Photosynthesis is an example of which type of chemical reaction?

Accepted Answer

Endergonic reaction

Question 3

Which equation correctly represents the overall reaction for photosynthesis?

Accepted Answer

$$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6$ + 6O_2$$

Question 4

Which of the following factors will NOT increase the rate of a chemical reaction?

Accepted Answer

Decreasing the concentration of reactants

Question 5

Enzymes are described as biological catalysts because they:

Accepted Answer

Lower the activation energy required for a reaction to occur

Question 6

Which of the following statements about enzyme activity is TRUE?

Accepted Answer

Enzyme activity is optimal at a specific pH and temperature.

Question 7

A patient with Tay-Sachs disease is unable to break down certain lipids in the brain due to a deficiency in which type of molecule?

Accepted Answer

An enzyme

Question 8

Which property of water allows it to act as a cushion and protect the body's structures?

Accepted Answer

Its incompressibility and ability to absorb shock

Question 9

Why is water considered an excellent solvent for ionic and polar covalent solutes?

Accepted Answer

Because it forms hydration spheres around ions, allowing them to dissociate and interact

Question 10

Which of the following best describes an acid in aqueous solution?

Accepted Answer

A molecule that donates protons ($$H^+) $$and increases hydrogen ion concentration

Question 11

Which equation correctly shows the dissociation of hydrochloric acid in water?

Accepted Answer

$$HCl \rightarrow H^+ + Cl^-$$

Question 12

What does the pH scale measure?

Accepted Answer

The negative logarithm (base 10) of hydrogen ion concentration ($$[H^+])$$

Question 13

If a solution has a pH of 3, which of the following is TRUE?

Accepted Answer

It has a high concentration of hydrogen ions and is acidic.

Question 14

Which of the following best explains how a pH buffer works in blood?

Accepted Answer

It maintains equilibrium by releasing $$H^+$$ when pH rises and binding $$H^+$$ when pH falls.

Question 15

Which chemical equation represents the action of the carbonic acid buffer system when blood pH falls?

Accepted Answer

$$H_2CO_3 \rightarrow $$HCO_3$$^- + H^+$$

Question 16

A solution with a pH of 9 has which of the following characteristics?

Accepted Answer

Low $$[H^+]$$ and is basic

Question 17

Which of the following is a property of bases in aqueous solution?

Accepted Answer

They accept protons and release $$OH^-$$ ions into solution

Question 18

Which of the following would most likely denature an enzyme?

Accepted Answer

A drastic increase in temperature

Question 19

Which of the following is an example of a reversible chemical reaction in the body?

Accepted Answer

$$CO_2 + H_2O$$ \rightleftharpoons H_2CO_3$$

Enzymes, Water, Acids & Bases: Chemical Energetics and Biological Importance

Study Guide - Practice Questions