Question 1

Which subatomic particle determines the atomic number of an element, and what is its charge?

Accepted Answer

Proton; positive charge

Question 2

How many electrons can be found in the second electron shell of an atom, and why is this shell important for chemical bonding?

Accepted Answer

8 electrons; it is the outermost shell in many biologically important atoms and determines reactivity

Question 3

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electron pairs between atoms

Question 4

Which type of chemical bond is primarily responsible for the structure of water molecules?

Accepted Answer

Hydrogen bond

Question 5

A solution has a pH of 3. Which of the following statements is correct?

Accepted Answer

The solution is acidic and has a high concentration of H$$^+.$$

Question 6

Which of the following is an example of a synthesis (anabolic) reaction in the human body?

Accepted Answer

Combining amino acids to form a protein

Question 7

What is the main function of buffer systems in the body?

Accepted Answer

To maintain a stable pH by neutralizing excess acids or bases

Question 8

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule consists of two or more atoms bonded together, while a compound consists of two or more different elements bonded together

Question 9

Which of the following is a property of water that makes it vital for life?

Accepted Answer

It has a high heat capacity, allowing it to moderate temperature changes

Question 10

Which of the following best explains why some isotopes are radioactive?

Accepted Answer

They have an unstable ratio of protons to neutrons in the nucleus

Question 11

Which of the following is a correct example of a catabolic (decomposition) reaction?

Accepted Answer

Breakdown of proteins into amino acids

Question 12

Which of the following statements about ATP is correct?

Accepted Answer

ATP stores energy in the bonds between its phosphate groups

Question 13

Which of the following best describes a hydrophobic molecule?

Accepted Answer

A molecule that repels water and does not dissolve in it

Question 14

Which of the following is NOT a function of proteins in the human body?

Accepted Answer

Providing genetic information

Question 15

A patient is experiencing acidosis. Which buffer system in the blood helps to maintain pH homeostasis?

Accepted Answer

Bicarbonate buffer system

Question 16

Which of the following is an example of an electrolyte in the human body?

Accepted Answer

Sodium chloride (NaCl)

Question 17

Which of the following best describes the role of hydrogen bonds in protein structure?

Accepted Answer

They stabilize secondary and tertiary structures by forming between polar groups

Question 18

Which of the following is a correct statement about acids and bases?

Accepted Answer

Bases accept H$$^+$$ ions in solution

Question 19

Which of the following is a correct example of a polar covalent bond in the human body?

Accepted Answer

The bond between hydrogen and oxygen in a water molecule

Question 20

A solution contains 0.01 mol/L of H$$^+$$ ions. What is its pH?

Accepted Answer

$$\mathrm{pH} = -\log_{10}(0.01) = 2$$

Chapter 2 Study Guide: Atoms, Elements, Chemical Bonds, and Biomolecules

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