For AS level OCR Biology, PAG 02 - reducing sugars experiment, outline a method for a full quantitative test for reducing sugars.
Understand the Problem
The question is asking for a detailed method to perform a quantitative test for reducing sugars as part of the OCR Biology AS level Practical Investigation. This involves outlining the steps necessary to conduct the experiment, likely including sample preparation and the use of reagents.
Answer
Create a standard curve with known sugar concentrations, perform Benedict's test, use a colorimeter to measure absorbance, and compare than unknown sample's absorbance to the curve.
To perform a fully quantitative test for reducing sugars, you should create a standard curve using known concentrations of sugar and measure their color change with a colorimeter after performing Benedict's test. The unknown sample's concentration can be determined by comparison with this curve.
Answer for screen readers
To perform a fully quantitative test for reducing sugars, you should create a standard curve using known concentrations of sugar and measure their color change with a colorimeter after performing Benedict's test. The unknown sample's concentration can be determined by comparison with this curve.
More Information
A colorimeter allows for a precise, numerical measurement of color intensity after the reaction, giving a quantitative result. Benedict's test produces a visible color change due to the formation of a copper oxide precipitate.
Tips
Students often forget to heat the solution properly or do not calibrate the colorimeter correctly, affecting the accuracy of the results.
Sources
- AS Biology help - The Student Room - thestudentroom.co.uk
- Biochemical Tests: Reducing Sugars & Starch (OCR A Level Biology) - Save My Exams - savemyexams.com
