BIOL180 Lesson 3 Quiz – Biomolecules
and Enzymes Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationale 2026 Q&A| Instant
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1. Which class of biomolecules is primarily responsible for storing and
transmitting hereditary information?
A. Carbohydrates
B. Lipids
C. Proteins
D. Nucleic acids
Rationale: Nucleic acids, including DNA and RNA, store, transmit, and
express genetic information. DNA contains hereditary instructions, while
RNA participates in protein synthesis.
2. Which of the following is the monomer of proteins?
A. Monosaccharide
B. Fatty acid
C. Amino acid
D. Nucleotide
Rationale: Proteins are polymers composed of amino acid monomers
joined together by peptide bonds during dehydration synthesis.
, 3. Which element is commonly found in proteins but not always present
in carbohydrates or lipids?
A. Carbon
B. Hydrogen
C. Oxygen
D. Nitrogen
Rationale: Proteins contain nitrogen as part of their amino groups,
whereas carbohydrates and many lipids consist mainly of carbon,
hydrogen, and oxygen.
4. What type of reaction joins two amino acids together?
A. Hydrolysis
B. Oxidation
C. Reduction
D. Dehydration synthesis
Rationale: Dehydration synthesis removes a water molecule while forming
a peptide bond between two amino acids.
5. Which carbohydrate serves as the primary energy source for most
living cells?
A. Cellulose
B. Glycogen
C. Starch
D. Glucose
Rationale: Glucose is readily broken down through cellular respiration to
produce ATP, making it the primary fuel molecule for cells.
6. Glycogen is best described as:
A. A structural carbohydrate in plants
B. The storage form of glucose in animals
, C. A component of DNA
D. A membrane phospholipid
Rationale: Animals store excess glucose as glycogen, primarily in the liver
and skeletal muscles.
7. Which polysaccharide provides structural support in plant cell walls?
A. Glycogen
B. Chitin
C. Starch
D. Cellulose
Rationale: Cellulose consists of glucose molecules linked by β-glycosidic
bonds and forms rigid plant cell walls.
8. Which carbohydrate is commonly found in the exoskeletons of insects?
A. Glycogen
B. Cellulose
C. Starch
D. Chitin
Rationale: Chitin is a tough structural polysaccharide that strengthens
arthropod exoskeletons and fungal cell walls.
9. Which type of lipid is the major component of cell membranes?
A. Triglycerides
B. Steroids
C. Waxes
D. Phospholipids
Rationale: Phospholipids form bilayers because they possess hydrophilic
heads and hydrophobic tails, creating the structure of biological
membranes.
and Enzymes Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationale 2026 Q&A| Instant
Download Pdf
1. Which class of biomolecules is primarily responsible for storing and
transmitting hereditary information?
A. Carbohydrates
B. Lipids
C. Proteins
D. Nucleic acids
Rationale: Nucleic acids, including DNA and RNA, store, transmit, and
express genetic information. DNA contains hereditary instructions, while
RNA participates in protein synthesis.
2. Which of the following is the monomer of proteins?
A. Monosaccharide
B. Fatty acid
C. Amino acid
D. Nucleotide
Rationale: Proteins are polymers composed of amino acid monomers
joined together by peptide bonds during dehydration synthesis.
, 3. Which element is commonly found in proteins but not always present
in carbohydrates or lipids?
A. Carbon
B. Hydrogen
C. Oxygen
D. Nitrogen
Rationale: Proteins contain nitrogen as part of their amino groups,
whereas carbohydrates and many lipids consist mainly of carbon,
hydrogen, and oxygen.
4. What type of reaction joins two amino acids together?
A. Hydrolysis
B. Oxidation
C. Reduction
D. Dehydration synthesis
Rationale: Dehydration synthesis removes a water molecule while forming
a peptide bond between two amino acids.
5. Which carbohydrate serves as the primary energy source for most
living cells?
A. Cellulose
B. Glycogen
C. Starch
D. Glucose
Rationale: Glucose is readily broken down through cellular respiration to
produce ATP, making it the primary fuel molecule for cells.
6. Glycogen is best described as:
A. A structural carbohydrate in plants
B. The storage form of glucose in animals
, C. A component of DNA
D. A membrane phospholipid
Rationale: Animals store excess glucose as glycogen, primarily in the liver
and skeletal muscles.
7. Which polysaccharide provides structural support in plant cell walls?
A. Glycogen
B. Chitin
C. Starch
D. Cellulose
Rationale: Cellulose consists of glucose molecules linked by β-glycosidic
bonds and forms rigid plant cell walls.
8. Which carbohydrate is commonly found in the exoskeletons of insects?
A. Glycogen
B. Cellulose
C. Starch
D. Chitin
Rationale: Chitin is a tough structural polysaccharide that strengthens
arthropod exoskeletons and fungal cell walls.
9. Which type of lipid is the major component of cell membranes?
A. Triglycerides
B. Steroids
C. Waxes
D. Phospholipids
Rationale: Phospholipids form bilayers because they possess hydrophilic
heads and hydrophobic tails, creating the structure of biological
membranes.
