Biology Isa Specimen

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Section 1
These questions are about your investigation with DCPIP and measuring Vitamin C. You should use your own results, your graph/s and what you remember about doing your investigation to answer these questions. All answers should be in the spaces provided.

1What were you trying to find out in your investigation?
Complete the blank spaces in the sentence below.
I was trying to find out if the……………….………………………………………………..
………………………………………………………………………...……… depends on the
…………………………………………………………………………………………………
(1 mark)

2 (a) In your investigation, which was the independent variable that you deliberately changed?
…………………………………………………………………………………………...
(1 mark)
(b) What was the range of your independent variable?
…………………………………………………………………………………………...
…………………………………………………………………………………………...
(1 mark)

3 Did you repeat any of your readings?
Answer yes or no and give a reason for your answer
…………………………………………………………………………………………….........
(1 mark)

4 In your experiment you measured the number of drops of fruit juice required to remove the colour from the DCPIP solution.
(a) Was this a good method of measuring the Vitamin C content?
Answer yes or no and give a reason for your answer
…………………………………………………………………………………………...
(1 mark)

(b) If you had used measuring apparatus with a smaller scale division what would this have increased?
Tick the box beside the correct answer

Accuracy
Precision
Reliability
Validity
(1 mark)

5 Before you carried out your experiment, either you or your teacher would have carried out a preliminary test.
Why was this done?
…………………………………………………………………………………………….........
…………………………………………………………………………………………….........
(1 mark)

6 Look back to Question 1 where you wrote down what you were trying to find out.
Now write down what you did find out from this investigation.
…………………………………………………………………………………………….........
…………………………………………………………………………………………….........
…………………………………………………………………………………………….........
(1 mark)

7 Suggest an improved method of measuring how much of the fruit juice was required to
remove the colour from the DCPIP.
…………………………………………………………………………………………............
……………………………………………………………………………………………........
(1 mark)

8 Attach your tables of results and your chart or graph to the paper. Carry out a final check of your results and graph/s.
You will be awarded up to 6 marks for these.
(6 marks)
Section 2
These questions are also about the Vitamin C content of different foods. John works for a company that markets healthy drinks. He was investigating the natural content of Vitamin C in different foods prior to making up the drinks for sale. John decided to find out the natural Vitamin C content of a range of pure fruit juices. Here is his table of results.

Fruit juiceVitamin C content /
mg per 100g
Lime29
Kiwi fruit98
Lemon46
Blackcurrant175
Distilled water2
Pineapple15
Orange53

9(a)John tested the Vitamin C content of distilled water. Why did he do this?
…………………………………………………………………………………….........
(1 mark)

(b)In John’s experiment the distilled water was found to contain 2 mg per 100g of
Vitamin C.
What can you say about the method John was using?
…………………………………………………………………………………….........
(1 mark)

(c)Explain what John should do with his raw data to take account of the result for distilled water.
…………………………………………………………………………………….........
(1 mark)

10 Write down one variable that John should have controlled or monitored during his investigation.
…………………………………………………………………………………………….........
(1 mark)

11 (a) Look at the first column in the table, headed ‘Fruit’.
What type of variable is this?
Draw a ring around the correct answer
ContinuousCategoricDiscreteOrdered
(1 mark)

(b) Explain the answer you have chosen for part (a).
………………………………………………………………………………………............
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