1.3 Nutrition and Food Tests
Food-test reagents and results, biological molecules, food energy, balanced diet and interpretation of nutrition evidence.
How to study for CCEA GCSE Biology
Learn each process as a structure-and-mechanism chain, use data with units, and prepare every prescribed practical from planning through conclusion and evaluation.
Core concepts
Concept 1
Benedict's, iodine, Biuret and ethanol tests identify reducing sugar, starch, protein and lipid through defined positive results.
Exam cue: Name the reagent, starting colour, procedure and positive result rather than giving only a nutrient name.
Concept 2
Carbohydrates, lipids and proteins differ in their building blocks and roles in energy, storage, structure and cell function.
Exam cue: Separate the amount of energy released by a sample from energy per gram.
Concept 3
Energy-content investigations require comparable sample masses, measured temperature change and awareness that much released heat is lost to the surroundings.
Exam cue: Use dietary data to explain a specific deficiency, excess or energy imbalance instead of labelling one food as simply healthy or unhealthy.
Risk pitfalls and guardrails
Calling a brick-red Benedict's result evidence for starch.
Guardrail: Do not import an England board, Single Award or Double Award structure, and do not replace a biological mechanism with a vague purpose statement.
Comparing burned foods from temperature rise alone when sample mass differs.
Guardrail: Do not import an England board, Single Award or Double Award structure, and do not replace a biological mechanism with a vague purpose statement.
Treating protein as the body's preferred immediate energy source.
Guardrail: Do not import an England board, Single Award or Double Award structure, and do not replace a biological mechanism with a vague purpose statement.
Memory anchors
Benedict's test
Heat with Benedict's solution; reducing sugar can produce a brick-red precipitate.
Iodine test
Iodine solution changes from yellow-brown to blue-black when starch is present.
Biuret test
Biuret reagent changes from blue to lilac or purple when protein is present.
Ethanol emulsion test
A white emulsion after the ethanol procedure indicates lipid.
Energy per gram
Energy transferred divided by the mass of food burned.
Balanced diet
An intake providing appropriate energy and nutrients for the person's needs.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
A food solution changes Benedict's reagent from blue to a brick-red precipitate after heating. What is present?
Which result is a positive iodine test for starch?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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