Campbell Biology 12e by Urry —
Complete Practice Test Bank with 300
Questions & Rationales
1. Which characteristic is shared by all living organisms?
A. Ability to photosynthesize
B. Ability to maintain an internal environment
C. Presence of chloroplasts
D. Ability to move from place to place
Answer: B. Ability to maintain an internal environment
Rationale: Homeostasis, or maintaining relatively stable internal conditions, is a fundamental
characteristic of life.
2. Which subatomic particle has a negative charge?
A. Proton
B. Neutron
C. Electron
D. Nucleus
Answer: C. Electron
Rationale: Electrons carry a negative electrical charge, whereas protons are positive and
neutrons are neutral.
3. The atomic number of an element represents the number of:
A. Neutrons
B. Protons
C. Electrons plus neutrons
D. Protons plus neutrons
Answer: B. Protons
Rationale: The atomic number is defined by the number of protons in the nucleus.
4. Atoms of the same element that differ in neutron number are called:
A. Ions
B. Isomers
C. Isotopes
D. Polymers
,Answer: C. Isotopes
Rationale: Isotopes have the same number of protons but different numbers of neutrons.
5. Which bond involves the sharing of electrons between atoms?
A. Ionic bond
B. Covalent bond
C. Hydrogen bond
D. Peptide bond
Answer: B. Covalent bond
Rationale: Covalent bonds form when atoms share one or more pairs of electrons.
6. Water is considered polar because:
A. It contains ionic bonds
B. Electrons are shared equally
C. Oxygen attracts shared electrons more strongly than hydrogen
D. Hydrogen has more electrons than oxygen
Answer: C. Oxygen attracts shared electrons more strongly than hydrogen
Rationale: Unequal electron sharing gives oxygen a partial negative charge and hydrogen
partial positive charges.
7. A substance with a pH of 3 is:
A. Strongly basic
B. Slightly basic
C. Neutral
D. Acidic
Answer: D. Acidic
Rationale: Values below 7 on the pH scale indicate acidic conditions.
8. Which property of water helps moderate temperature changes?
A. Low density of ice
B. High specific heat
C. Solvent capacity
D. Cohesion
Answer: B. High specific heat
Rationale: Water absorbs substantial heat with relatively little temperature change, helping
stabilize temperatures.
9. Which molecule is a monosaccharide?
A. Glucose
B. Starch
C. Glycogen
D. Cellulose
,Answer: A. Glucose
Rationale: Glucose is a six-carbon monosaccharide and an important cellular energy source.
10. What type of reaction joins monomers by removing water?
A. Hydrolysis
B. Dehydration reaction
C. Oxidation
D. Reduction
Answer: B. Dehydration reaction
Rationale: Dehydration reactions form covalent bonds while removing a molecule of water.
11. Which carbohydrate is the primary structural component of plant cell walls?
A. Glycogen
B. Chitin
C. Cellulose
D. Starch
Answer: C. Cellulose
Rationale: Cellulose is a structural polysaccharide that forms strong plant cell walls.
12. Animals commonly store excess glucose as:
A. Cellulose
B. Glycogen
C. Chitin
D. Sucrose
Answer: B. Glycogen
Rationale: Animals store glucose primarily as the branched polysaccharide glycogen.
13. Which group of biological molecules includes fats and phospholipids?
A. Proteins
B. Nucleic acids
C. Lipids
D. Carbohydrates
Answer: C. Lipids
Rationale: Fats, oils, phospholipids, and steroids are major classes of lipids.
14. A phospholipid contains:
A. Three amino acids and glycerol
B. Glycerol, fatty acids, and a phosphate group
C. Glucose and fructose
D. Nucleotides and phosphate
, Answer: B. Glycerol, fatty acids, and a phosphate group
Rationale: Phospholipids contain a glycerol backbone, two fatty acid tails, and a phosphate-
containing head.
15. Which fatty acids contain one or more double bonds?
A. Saturated fatty acids
B. Unsaturated fatty acids
C. Amino acids
D. Nucleotides
Answer: B. Unsaturated fatty acids
Rationale: Unsaturated fatty acids contain one or more carbon-carbon double bonds.
16. Proteins are polymers composed of:
A. Nucleotides
B. Monosaccharides
C. Amino acids
D. Fatty acids
Answer: C. Amino acids
Rationale: Amino acids are linked by peptide bonds to form polypeptides and proteins.
17. The bond between two amino acids is called a:
A. Glycosidic bond
B. Hydrogen bond
C. Peptide bond
D. Phosphodiester bond
Answer: C. Peptide bond
Rationale: Peptide bonds connect amino acids in a polypeptide chain.
18. Which level of protein structure refers to the amino acid sequence?
A. Primary
B. Secondary
C. Tertiary
D. Quaternary
Answer: A. Primary
Rationale: Primary structure is the specific linear sequence of amino acids.
19. Alpha helices and beta sheets are features of which protein structure?
A. Primary
B. Secondary
C. Tertiary
D. Quaternary
Complete Practice Test Bank with 300
Questions & Rationales
1. Which characteristic is shared by all living organisms?
A. Ability to photosynthesize
B. Ability to maintain an internal environment
C. Presence of chloroplasts
D. Ability to move from place to place
Answer: B. Ability to maintain an internal environment
Rationale: Homeostasis, or maintaining relatively stable internal conditions, is a fundamental
characteristic of life.
2. Which subatomic particle has a negative charge?
A. Proton
B. Neutron
C. Electron
D. Nucleus
Answer: C. Electron
Rationale: Electrons carry a negative electrical charge, whereas protons are positive and
neutrons are neutral.
3. The atomic number of an element represents the number of:
A. Neutrons
B. Protons
C. Electrons plus neutrons
D. Protons plus neutrons
Answer: B. Protons
Rationale: The atomic number is defined by the number of protons in the nucleus.
4. Atoms of the same element that differ in neutron number are called:
A. Ions
B. Isomers
C. Isotopes
D. Polymers
,Answer: C. Isotopes
Rationale: Isotopes have the same number of protons but different numbers of neutrons.
5. Which bond involves the sharing of electrons between atoms?
A. Ionic bond
B. Covalent bond
C. Hydrogen bond
D. Peptide bond
Answer: B. Covalent bond
Rationale: Covalent bonds form when atoms share one or more pairs of electrons.
6. Water is considered polar because:
A. It contains ionic bonds
B. Electrons are shared equally
C. Oxygen attracts shared electrons more strongly than hydrogen
D. Hydrogen has more electrons than oxygen
Answer: C. Oxygen attracts shared electrons more strongly than hydrogen
Rationale: Unequal electron sharing gives oxygen a partial negative charge and hydrogen
partial positive charges.
7. A substance with a pH of 3 is:
A. Strongly basic
B. Slightly basic
C. Neutral
D. Acidic
Answer: D. Acidic
Rationale: Values below 7 on the pH scale indicate acidic conditions.
8. Which property of water helps moderate temperature changes?
A. Low density of ice
B. High specific heat
C. Solvent capacity
D. Cohesion
Answer: B. High specific heat
Rationale: Water absorbs substantial heat with relatively little temperature change, helping
stabilize temperatures.
9. Which molecule is a monosaccharide?
A. Glucose
B. Starch
C. Glycogen
D. Cellulose
,Answer: A. Glucose
Rationale: Glucose is a six-carbon monosaccharide and an important cellular energy source.
10. What type of reaction joins monomers by removing water?
A. Hydrolysis
B. Dehydration reaction
C. Oxidation
D. Reduction
Answer: B. Dehydration reaction
Rationale: Dehydration reactions form covalent bonds while removing a molecule of water.
11. Which carbohydrate is the primary structural component of plant cell walls?
A. Glycogen
B. Chitin
C. Cellulose
D. Starch
Answer: C. Cellulose
Rationale: Cellulose is a structural polysaccharide that forms strong plant cell walls.
12. Animals commonly store excess glucose as:
A. Cellulose
B. Glycogen
C. Chitin
D. Sucrose
Answer: B. Glycogen
Rationale: Animals store glucose primarily as the branched polysaccharide glycogen.
13. Which group of biological molecules includes fats and phospholipids?
A. Proteins
B. Nucleic acids
C. Lipids
D. Carbohydrates
Answer: C. Lipids
Rationale: Fats, oils, phospholipids, and steroids are major classes of lipids.
14. A phospholipid contains:
A. Three amino acids and glycerol
B. Glycerol, fatty acids, and a phosphate group
C. Glucose and fructose
D. Nucleotides and phosphate
, Answer: B. Glycerol, fatty acids, and a phosphate group
Rationale: Phospholipids contain a glycerol backbone, two fatty acid tails, and a phosphate-
containing head.
15. Which fatty acids contain one or more double bonds?
A. Saturated fatty acids
B. Unsaturated fatty acids
C. Amino acids
D. Nucleotides
Answer: B. Unsaturated fatty acids
Rationale: Unsaturated fatty acids contain one or more carbon-carbon double bonds.
16. Proteins are polymers composed of:
A. Nucleotides
B. Monosaccharides
C. Amino acids
D. Fatty acids
Answer: C. Amino acids
Rationale: Amino acids are linked by peptide bonds to form polypeptides and proteins.
17. The bond between two amino acids is called a:
A. Glycosidic bond
B. Hydrogen bond
C. Peptide bond
D. Phosphodiester bond
Answer: C. Peptide bond
Rationale: Peptide bonds connect amino acids in a polypeptide chain.
18. Which level of protein structure refers to the amino acid sequence?
A. Primary
B. Secondary
C. Tertiary
D. Quaternary
Answer: A. Primary
Rationale: Primary structure is the specific linear sequence of amino acids.
19. Alpha helices and beta sheets are features of which protein structure?
A. Primary
B. Secondary
C. Tertiary
D. Quaternary
