$$\text{Mass number} = \text{Number of protons} + \text{Number of neutrons}$$

Question 1

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

Accepted Answer

An atom is the smallest unit of a chemical element, while a molecule is made up of two or more atoms bonded together.

Question 2

Which subatomic particle determines the atomic number of an element?

Accepted Answer

Proton

Question 3

If an atom has 6 protons, 6 neutrons, and 6 electrons, what is its atomic number and mass number?

Accepted Answer

Atomic number: 6, Mass number: 12

Question 4

Which of the following best explains why isotopes of an element have different mass numbers?

Accepted Answer

They have different numbers of neutrons.

Question 5

Which of the following is the correct formula for calculating the mass number of an atom?

Accepted Answer

$$	ext{Mass number} = 	ext{Number of protons} + 	ext{Number of neutrons}$$

Question 6

A sodium atom has 11 protons, 12 neutrons, and 11 electrons. What is its mass number?

Accepted Answer

$$23$$

Question 7

Which of the following statements about ATP (adenosine triphosphate) is correct?

Accepted Answer

ATP is the main energy source for cellular processes.

Question 8

Which process describes the breakdown of molecules to release energy?

Accepted Answer

Catabolism

Question 9

Which of the following best describes the role of enzymes in the body?

Accepted Answer

They speed up chemical reactions by lowering activation energy.

Question 10

A patient is diagnosed with a metabolic disorder that prevents the synthesis of ATP. Which cellular process would be most directly affected?

Accepted Answer

Active transport across cell membranes

Question 11

Which of the following is a correct definition of a peptide?

Accepted Answer

A short chain of amino acids linked by peptide bonds

Question 12

Which of the following best describes the relationship between hydrolysis and dehydration synthesis?

Accepted Answer

Hydrolysis breaks down molecules by adding water, while dehydration synthesis builds molecules by removing water.

Question 13

Which of the following is a real-life example of anabolism?

Accepted Answer

The synthesis of muscle proteins after exercise

Question 14

Which of the following best explains why enzymes are specific to their substrates?

Accepted Answer

The active site of an enzyme has a unique shape that fits only specific substrates.

Question 15

Which of the following is the correct sequence for the levels of organization in the human body, from smallest to largest?

Accepted Answer

Atom → Molecule → Cell → Tissue → Organ

Question 16

A scientist discovers a new isotope of carbon with 6 protons and 8 neutrons. What is the mass number of this isotope?

Accepted Answer

$$14$$

Question 17

Which of the following best describes the function of nucleic acids in the body?

Accepted Answer

They store and transmit genetic information.

Question 18

Which of the following is a correct example of a molecule?

Accepted Answer

$$	ext{H}_2	ext{O} ($$water)

Question 19

Which of the following best explains why water is important for hydrolysis reactions in the body?

Accepted Answer

Water is used to break chemical bonds during hydrolysis.

Question 20

Which of the following is a real-life application of understanding isotopes in medicine?

Accepted Answer

Using radioactive isotopes in imaging techniques such as PET scans

Atoms and the Chemistry of Life: Study Notes for Anatomy & Physiology

Study Guide - Practice Questions