Weaning rusks contain two main types of carbohydrate: starch and reducing sugars (such as maltose).
Describe the chemical tests that could be used to show the presence of these two types of carbohydrate in a sample of a weaning rusk.
Include a risk assessment in your answer.
A student investigated three different brands of weaning rusks to see how quickly they are digested in the mouth.
For each brand of weaning rusk, the student:
Their results are shown below:
| Brand of weaning rusk | Time taken for rusk to taste sweet (seconds) |
|---|---|
| Brand X | 34 |
| Brand Y | 51 |
| Brand Z | 23 |
Answer the following questions based on this study:
What was the dependent variable in this investigation?
Give one control variable that the student used, or should have used, in this investigation.
Explain why the weaning rusks began to taste sweet during the investigation.
Suggest one reason why the results of this investigation might not be valid. Do not refer to control variables in your answer.
44 exam-style questions on AQA GCSE Biology 2.2 Animal tissues, organs and organ systems, covering 2.2.1 The human digestive system, 2.2.2 The heart and blood vessels, 2.2.3 Blood, 2.2.4 Coronary heart disease: a non-communicable disease, 2.2.5 Health issues, 2.2.6 The effect of lifestyle on some non-communicable diseases, and 2.2.7 Cancer. Each one has a worked solution and a mark scheme showing where the marks go.