You will complete twenty-one required practical activities if you are studying GCSE combined science: Trilogy. You could be asked questions about the apparatus, methods, safety precautions, results, analysis and evaluation of these experiments.
In this Cell Biology section there are two required practical activities:
There will be a number of different types of practical based questions. Some will be on the set required practicals, some will cover the working scientifically terms and some will be on other science practicals which you might have done in class. Use all the information given in the question particularly any diagrams to help you understand what the question is about.
These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.
A student is investigating the process of mitosis with a microscope.
The hazard warning label on the chromosome stain they use states:
Suggest three safety precautions they should take.
Describe how to prepare a stained slide of onion epidermal tissue.
These are the main points that the examiner will be looking for, but you do not have to match every word.
In questions based on Required Practicals, the examiner will make allowances for instances where the equipment used in one school may be slightly different from another, the level of detail you’ve added, or if your answer is worded in a slightly different way.
(a) A student investigated the effects of osmosis in potato tissue by placing potato cylinders in different concentrations of sugar solution.
Their results are shown below (as a percentage).
Identify the anomalous result. [1 mark]
|Sugar solution - low concentration||+4||+5||+4||+6||+5||+6||+5||+6||+6|
|Sugar solution - high concentration||-12||-13||-15||-11||-16||-2||-15||-17||-15|
Experiment 6, high concentration of sugar.
(b) Calculate the mean change in mass for each concentration. Do not include the anomalous result from Experiment 6 in your calculations.
Give your answer to one decimal place. [2 marks]
(c) Explain why the student expressed change in mass as a percentage. [3 marks]
Describe how you would set up a microscope to examine a prepared slide under high power. [6 marks]
Your answer should be made up from the following points: