exam questions

Question 1

A different student did this investigation. He did not have a colorimeter.
Describe a method this student could use to prepare colour standards and use them
to give data for the total anthocyanin extracted.

Answer 1

1. Use known concentration of blueberry
   juice/extract
   OR
   Use known concentration of
   anthocyanin/pigment (solution)
   OR
   Use known concentration of (extraction) solvent
   to be added to blueberries;
2. Prepare dilution series;
3. Compare (results) with colour standards to give score/value/concentration;

Question 2

Explain why death of alveolar epithelium cells reduces gas exchange in human lungs.
[3 marks

Answer 2

1. Reduced surface area;
2. Increased distance for diffusion;
3. Reduced rate of gas exchange;

Question 3

Define ‘non-coding base sequences’ and describe where the non-coding multiple
repeats are positioned in the genome.

Answer 3

1. DNA that does not code for protein/polypeptides
   OR
   DNA that does not code for (sequences of)
   amino acids
   OR
   DNA that does not code for tRNA/rRNA;
2. (Positioned) between genes;