A sports drink company claims that their product contains glucose, amino acids and mineral ions. Explain why each of these substances is important for the functioning of cells in the human body.

OCR A-Level Biology B — Advancing Biology (H422) — 2.2 Biological molecules including biochemistry · Explain · 5 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Athletes are often advised to consume sports drinks before and after exercise. These drinks are formulated to contain a range of biological molecules that the body needs.

Model answer (5 marks)

1. Glucose is the main fuel for cellular respiration, providing ATP that powers active transport and other energy‑requiring processes.
2. The ATP produced is essential for active transport across membranes, such as Na⁺/K⁺‑ATPase.
3. Amino acids are the monomers that build proteins.
4. Proteins perform key functions – for example, enzymes catalyse reactions, membrane proteins form transport channels, and actin/myosin proteins enable muscle contraction.
5. Mineral ions such as Na⁺, K⁺, Ca²⁺ and Mg²⁺ are required for nerve impulse transmission, enzyme activity and maintaining osmotic balance (water potential) in cells.

Examiner tips

  • Use the exact terms from the mark scheme (glucose, ATP, active transport, amino acids, proteins, enzymes, membrane structure, muscle contraction, mineral ions, nerve impulse, enzyme function, osmosis).
  • Show the link between glucose → ATP → active transport.
  • Mention a specific protein function (e.g. enzyme).
  • State a specific ion function (e.g. Na⁺/K⁺‑ATPase).

Common mistakes

  • Confusing glucose with other sugars or claiming it is only a structural component.
  • Lumping all proteins together without naming a specific function.

Mark scheme (5 marks)

  1. Glucose is used in respiration to release energy
  2. Energy (from respiration) is needed for active transport or other named cellular process
  3. Amino acids are used to make proteins / are the building blocks of proteins
  4. Proteins are needed for a named function such as enzymes, cell membrane structure, or muscle contraction
  5. Mineral ions are needed for a named cellular function such as nerve impulse transmission, enzyme function, or maintaining water potential / osmosis

Key terms in this question

glucose · amino acids · mineral ions

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