Exam skills
What the paper asks you to do
- State test reagents and positive results precisely
- Link molecular structure to biological use
- Interpret food-test data
Foundations
Biological molecules
Connect carbohydrates, lipids and proteins with their building blocks, biological roles and standard food tests.5090 syllabus routeConcept · skill · exam language
What to know
Build the topic around four anchors.
- 01Elements and subunits
- 02Starch, glycogen and cellulose
- 03Fats and proteins
- 04Benedict's, iodine, biuret and emulsion tests
Common mistakes
Where marks disappear
- Confusing the biuret and Benedict's tests
- Calling every carbohydrate sugar
- Forgetting to heat Benedict's reagent safely
Structured practice
Answer these without looking back.
For each prompt, write the biological chain clearly enough that every mark-worthy link is visible.
- 01Design a test for reducing sugar.
- 02Explain one role each of lipid and protein.
- 03Interpret a table of food-test results.
Continue learning
Read the connected explanation.
Connect water, carbohydrates, lipids and proteins to the chemical features that make their biological roles possible.
This independent teaching resource follows the Cambridge O Level Biology 5090 syllabus direction and is not endorsed by Cambridge International Education.