| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Biology |
| Lesson Topic: describe and carry out a test to identify the presence of non-reducing sugars, using acid hydrolysis and Benedict’s solution |
Learning Objective/s:
- Describe the structural difference between reducing and non‑reducing sugars.
- Explain how acid hydrolysis converts non‑reducing sugars into reducing sugars.
- Perform the full test sequence (hydrolysis, neutralisation, Benedict’s reaction) and interpret colour changes.
- Evaluate results using appropriate positive and negative controls.
- Identify common sources of error and suggest corrective actions.
|
Materials Needed:
- Test tubes (minimum 4) and rack
- Hydrochloric acid (1 M)
- Sodium hydroxide (2 M)
- Freshly prepared Benedict’s solution
- Unknown sample solution (2 mL) and glucose standard
- Distilled water
- Boiling water bath or hot plate
- Protective gloves, goggles, lab coat
|
Introduction:
Begin with a quick demonstration of a classic Benedict’s test that produces a bright brick‑red precipitate, prompting students to wonder why some sugars fail to react. Review the concepts of reducing versus non‑reducing sugars covered in the previous lesson. Explain that today’s success criteria are to correctly carry out the hydrolysis‑Benedict’s procedure and accurately interpret the observations.
|
Lesson Structure:
- Do‑now (5’) – Students label a worksheet with the steps of the Benedict’s test and predict outcomes for reducing vs non‑reducing sugars (quick check).
- Mini‑lecture (10’) – Recap sugar structure, hydrolysis mechanism, safety, and show a flow‑chart diagram.
- Demonstration (10’) – Teacher performs the hydrolysis and Benedict’s test on a known sucrose sample, highlighting colour change.
- Guided practice (20’) – Pairs set up tubes A–D, add reagents, heat, and record results while teacher circulates.
- Data analysis (10’) – Groups compare observations with controls, fill an interpretation table, and discuss discrepancies.
- Error‑analysis discussion (5’) – Review common mistakes and have students suggest preventive measures.
- Exit ticket (5’) – Each student writes one key point about why acid hydrolysis is required and one potential error to watch for.
|
Conclusion:
Summarise that non‑reducing sugars become detectable only after acid hydrolysis converts them to reducing monosaccharides, and that the colour intensity reflects sugar amount. Collect exit tickets as a quick retrieval check and assign homework to write a short lab report describing the procedure and interpreting hypothetical results.
|