Lesson 2.1.2c

2.1.2c Inorganic ions and biochemical analysis Quiz: OCR Biology, Unit 1

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 2.1.2c, Inorganic ions and biochemical analysis: 20 multiple choice questions for the OCR Biology (H020), Unit 1: Foundations in biology, written with Revision Ninja.

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The 20 questions

  1. Which ion is a cofactor for the enzyme amylase?

    • Calcium ion (Ca2+)
    • Nitrate ion (NO3-)
    • Chloride ion (Cl-)
    • Hydrogen ion (H+)

  2. Which two ions are primarily involved in generating nerve impulses in neurones?

    • Sodium and potassium
    • Hydrogen and chloride
    • Calcium and magnesium
    • Iron and sodium

  3. What is the primary biological role of hydrogencarbonate ions in human blood?

    • Activating enzymes
    • Buffering blood pH
    • Regulating water potential
    • Transporting oxygen

  4. Which ion is a key component of ATP and nucleotides?

    • Hydroxide (OH-)
    • Ammonium (NH4+)
    • Phosphate (PO4 3-)
    • Calcium (Ca2+)

  5. Which symbol represents the ammonium ion?

    • NO3-
    • HCO3-
    • NH3
    • NH4+

  6. Which specific metal ion is the central component of the haem group in haemoglobin?

    • Zinc
    • Calcium
    • Iron
    • Magnesium

  7. Which biological molecules do plants synthesise using absorbed nitrate ions?

    • Amino acids
    • Triglycerides
    • Starch
    • Cellulose

  8. What does a brick-red precipitate in Benedict's test indicate?

    • Reducing sugar
    • Protein
    • Starch
    • Non-reducing sugar

  9. Paper chromatography separates the sample of a sugar mixture. The solvent front moves 6.0 cm and the solute moves 3.0 cm. What is the Rf value?

    • 0.5
    • 2.0
    • 0.25
    • 0.33

  10. A spot moves 6.0 cm while the solvent front moves 8.0 cm. What is the Rf value?

    • 0.25
    • 1.33
    • 0.75
    • 0.48

  11. A colorimeter calibration gives absorbance 0.20 for a 0.5 mmol/dm3 standard, with a linear response. A sample reads 0.40. What is the concentration?

    • 2.0 mmol/dm3
    • 0.25 mmol/dm3
    • 1.0 mmol/dm3
    • 0.8 mmol/dm3

  12. Which metallic ion is essential at the centre of a chlorophyll molecule in green plants?

    • Magnesium
    • Copper
    • Sodium
    • Iron

  13. Which factor must remain constant for valid Rf comparisons in chromatography?

    • Starting temperature
    • Container colour
    • Solvent and paper
    • Sample volume

  14. What common cellular role do calcium ions play in muscle contraction and blood clotting?

    • Structural fibres
    • Energy substrates
    • Osmotic solutes
    • Signalling cofactors

  15. Why can Rf values for the same compound vary between different chromatography runs?

    • Solvent dependency
    • Spot volume
    • Sample purity
    • Molecular weight

  16. Which biochemical test is routinely used to detect the presence of reducing sugars?

    • Biuret test
    • Emulsion test
    • Benedict's test
    • Iodine test

  17. A standard curve is linear from 0.2 to 0.8 mmol/dm3, with absorbance 0.10 at 0.2 and 0.40 at 0.8. An unknown reads absorbance 0.30. What is its concentration?

    • 0.6 mmol/dm3
    • 0.15 mmol/dm3
    • 0.3 mmol/dm3
    • 1.2 mmol/dm3

  18. What happens to ion gradients when a metabolic inhibitor stops cellular ATP production?

    • Gradients steepen
    • Gradients invert
    • Gradients dissipate
    • Gradients freeze

  19. What is a major role of potassium ions inside animal cells?

    • Oxygen transport
    • Enzyme denaturation
    • Spindle formation
    • Resting potential

  20. Which reagent is added to test for the presence of peptide bonds in proteins?

    • Benedict's reagent
    • Biuret reagent
    • Iodine solution
    • Ethanol

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