AQA A-level BIOLOGY Paper 1 | June 2023

Answer all questions in the spaces provided. box 0 1 . 1 Give the three structural features found in all virus particles and describe the function of one of these features. [2 marks] 1 2 3 Function of one named feature . Explain why viruses are described as acellular and non-living. [2 marks] . Give one reason why antibiotics are not effective against viruses. [1 mark] . Chitin is a polysaccharide. The chitin monomer is a β-glucose molecule with one OH group replaced by an NHCOCH3 group. NHCOCH3 can be represented by N(Ac). Figure 1 shows the monomer that forms chitin and the chitin polymer. Figure 1 Question 2 continues on the next page box Turn over ► . Chitin keeps the tracheae open in the tracheal system of gas exchange in an insect. Gas exchange does not occur in the tracheae. Explain the importance of one adaptation of the gas exchange surface in the tracheal system of an insect. box [2 marks]