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3.1.1 Monomers and polymers

AQA A-level Biology 3.1.1 practice on Monomers and polymers, with free MCQs, clues and worked explanations drawn from the Biological molecules section of specification 7402.

Specification route
3.1.1
Question bank
23 questions
Course stage
AS / Year 12

Sample questions

QUESTION 1 · 3.1.1 · LEVEL 4

Which list contains ONLY polymers?

  • DNA, cellulose, glycogen
  • Starch, triglyceride, polypeptide
  • RNA, sucrose, glycogen
  • Maltose, DNA, cellulose
Show clue

Remember that triglycerides are macromolecules but not polymers, and disaccharides are just dimers.

Show answer and explanation

Answer: DNA, cellulose, glycogen

Polymers are molecules made from a large number of monomers joined together. DNA, cellulose, and glycogen are all polymers. Triglycerides are not polymers. Sucrose and maltose are disaccharides.

QUESTION 2 · 3.1.1 · LEVEL 1

Which of the following molecules is an example of a monomer?

  • Nucleotide
  • Glycogen
  • Triglyceride
  • Polypeptide
Show clue

Monomers are the smaller units from which larger polymer molecules are made.

Show answer and explanation

Answer: Nucleotide

Monosaccharides, amino acids and nucleotides are examples of monomers. Glycogen and polypeptides are polymers, while triglycerides are non-polymeric macromolecules.

QUESTION 3 · 3.1.1 · LEVEL 2

Which statement correctly describes a condensation reaction?

  • It joins two molecules together with the formation of a chemical bond and involves the elimination of a molecule of $H_{2}O$.
  • It breaks a chemical bond between two molecules and involves the use of a $H_{2}O$ molecule.
  • It joins two molecules together with the formation of a chemical bond and involves the use of a $H_{2}O$ molecule.
  • It breaks a chemical bond between two molecules and involves the elimination of a molecule of $H_{2}O$.
Show clue

Think about how water is involved when building a larger molecule from smaller ones.

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Answer: It joins two molecules together with the formation of a chemical bond and involves the elimination of a molecule of $H_{2}O$.

A condensation reaction joins two molecules together with the formation of a chemical bond and involves the elimination of a molecule of water.

QUESTION 4 · 3.1.1 · LEVEL 1

What type of reaction is required to break a chemical bond between two biological molecules?

  • Hydrolysis reaction
  • Condensation reaction
  • Oxidation reaction
  • Reduction reaction
Show clue

The name of this reaction literally means 'water splitting'.

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Answer: Hydrolysis reaction

A hydrolysis reaction breaks a chemical bond between two molecules and involves the use of a water molecule.

QUESTION 5 · 3.1.1 · LEVEL 1

Which of the following statements correctly distinguishes a polymer from other large molecules?

  • Polymers are molecules made from a large number of monomers joined together.
  • Polymers are any molecules with a high molecular mass.
  • Polymers are made exclusively of carbon, hydrogen, and oxygen.
  • Polymers are formed by breaking down larger functional units.
Show clue

Think about the prefix 'poly-', meaning many.

Show answer and explanation

Answer: Polymers are molecules made from a large number of monomers joined together.

Polymers are specifically defined as molecules made from a large number of monomers joined together. Large molecules like triglycerides are not polymers because they are not made of repeating monomeric units.

QUESTION 6 · 3.1.1 · LEVEL 2

A molecule is broken down into smaller, repeating units by the addition of water. What is this process called?

  • A hydrolysis reaction of a polymer into monomers
  • A condensation reaction of a polymer into monomers
  • A hydrolysis reaction of monomers into a polymer
  • A condensation reaction of monomers into a polymer
Show clue

Using water ('hydro') to break ('lysis') a large chain.

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Answer: A hydrolysis reaction of a polymer into monomers

A hydrolysis reaction breaks a chemical bond between two molecules and involves the use of a water molecule. Since repeating units are involved, it is breaking a polymer down into monomers.

QUESTION 7 · 3.1.1 · LEVEL 1

Which statement provides the most accurate definition of monomers in biological systems?

  • They are the smaller units from which larger molecules are made.
  • They are long chains of repeating units joined by condensation reactions.
  • They are universally composed of carbon, hydrogen, and oxygen only.
  • They are complex macromolecules that form the structural components of cells.
Show clue

Think about the building blocks of large biological molecules.

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Answer: They are the smaller units from which larger molecules are made.

Monomers are the smaller units from which larger molecules are made. Polymers are the larger molecules made from these repeating units.

QUESTION 8 · 3.1.1 · LEVEL 2

Which of the following lists contains ONLY examples of biological monomers?

  • Monosaccharides, amino acids, and nucleotides
  • Glucose, glycogen, and nucleotides
  • Amino acids, polypeptides, and monosaccharides
  • Fatty acids, triglycerides, and amino acids
Show clue

Identify the smallest individual repeating units that can form polymers.

Show answer and explanation

Answer: Monosaccharides, amino acids, and nucleotides

Monosaccharides, amino acids and nucleotides are examples of monomers. Glycogen and polypeptides are polymers, while triglycerides are macromolecules but not polymers.

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