- Specification route
- 3.1.8
- Question bank
- 23 questions
- Course stage
- AS / Year 12
Practise this topic
23 standard questions. No sign-in required.
Practise Biology maths and data skills
Sessions use up to the requested number of available questions. Standard practice uses levels 1–5.
Sample questions
Which inorganic ion is directly responsible for determining the pH of an environment?
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pH is the negative logarithm of the concentration of this specific ion.
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Answer: Hydrogen ions ($H^{+}$)
Hydrogen-ion concentration determines acidity: as $[H^+]$ increases, pH falls. Hydrogen ions therefore link directly to pH in biological fluids and experimental solutions.
Which condition is necessary for the co-transport of glucose into the epithelial cells lining the ileum?
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The movement of glucose is coupled to the 'downhill' movement of another ion.
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Answer: A concentration gradient of sodium ions ($Na^{+}$) must be maintained across the cell membrane.
Sodium ions have a specific role in the co-transport of glucose and amino acids. $Na^{+}$ is actively pumped out of the cell, creating a gradient. $Na^{+}$ then diffuses back in through a co-transporter protein, bringing glucose with it against the glucose concentration gradient.
What is the biological role of iron ions ($Fe^{2+}$)?
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These ions are essential for oxygen transport in red blood cells.
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Answer: They act as a component of haemoglobin
Iron ions are recognised as a component of haemoglobin.
Which inorganic ion is vital for the co-transport of glucose and amino acids across cell membranes?
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This ion is actively pumped out of epithelial cells to maintain a concentration gradient in the ileum.
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Answer: Sodium ions ($Na^{+}$)
Sodium ions have a specific role in the co-transport of glucose and amino acids.
Which components of cells specifically rely on phosphate ions ($PO_{4}^{3-}$) for their formation?
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Look for molecules that require a phosphodiester bond or store energy in high-energy bonds.
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Answer: DNA and ATP
Phosphate ions act as components of DNA and of ATP.
Where in the organism do inorganic ions naturally occur in solution?
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These ions are dissolved throughout the internal environment.
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Answer: In the cytoplasm and body fluids of organisms
Inorganic ions occur in solution in the cytoplasm and body fluids of organisms, some in high concentrations and others in very low concentrations.
Which of the following correctly pairs an inorganic ion with its specific biological role?
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Match the metal ion to the oxygen-carrying pigment in red blood cells.
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Answer: Iron ions as a component of haemoglobin
Iron ions form part of the haem group in haemoglobin. Sodium ions are important in processes such as co-transport and nerve impulses; phosphate groups occur in molecules including ATP and nucleic acids; hydrogen ions determine pH.
What does a high concentration of hydrogen ions ($H^{+}$) in a solution indicate?
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The pH scale is inversely proportional to the concentration of these ions.
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Answer: The solution has a low pH.
A higher hydrogen-ion concentration means greater acidity and therefore a lower pH. A lower $[H^+]$ corresponds to a higher pH.
Practise this topic
23 standard questions are available (levels 1–5). No sign-in required.