June 2021 MS - Paper 1 AQA Biology AS-level.PDF

Question 1

This question is about mitosis in cells.
Figure 4 shows the arrangement of the genetic material in a cell during prophase.
Figure 4
0 4 . 1 Describe and explain the arrangement of the genetic material shown in Figure 4.

Answer 1

1. Chromosomes (are) becoming visible/distinct;
2. Because (still) condensing;
   OR
3. Chromosomes (arranged) at random/not lined
   up;
4. Because no spindle (activity);
   OR
   Because not attached to spindle fibres;

Question 2

Describe two differences between the structure of a tRNA molecule and the
structure of an mRNA molecule.

Question 3

0 4 . 3 Name the fixed position occupied by a gene on a DNA molecule.

Answer 3

locus

Question 4

4 . 4 Describe how a gene is a code for the production of a polypeptide. Do not include
information about transcription or translation in your answer.

Answer 4

1. (Because) base/nucleotide sequence;
2. (In) triplet(s);
3. (Determines) order/sequence of amino acid
   sequence/primary structure (in polypeptide);

Question 5

0 5 box . 1 Describe how the structure of glycogen is related to its function.

Answer 5

1. Helix/coiled/branched so compact;
2. Polymer of glucose so easily hydrolysed;
3. Branched so more ends for faster hydrolysis;
4. Glucose (polymer) so provides respiratory
   substrate for energy (release);
5. Insoluble so not (easily) lost (from cell)
   OR
   Insoluble so does not affect water
   potential/osmosis;

Question 6

0 5 . 2 Name the type of peptidase which will hydrolyse the bond labelled G in Figure 5.

Answer 6

Endopeptidase

Question 7

0 5 . 3 Give the number of different R groups in the polypeptide shown in Figure 5.

Answer 7

3