2023 AQA A-level BIOLOGY 7402/3 Paper 3 Question Paper & Mark scheme (Merged) June 2023 [VERIFIED]

2023 AQA A-level BIOLOGY 7402/3 Paper 3 Question Paper & Mark scheme (Merged) June 2023 [VERIFIED] Please write clearly in block capitals. Centre number Candidate number Surname Forename(s) Candidate signature I declare this is my own work. A-level BIOLOGY Paper 3 Wednesday 21 June 2023 Morning Time allowed: 2 hours Materials For this paper you must have: • a ruler with millimetre measurements • a scientific calculator. Instructions • Use black ink or black ball-point pen. • Fill in the boxes at the top of this page. • Answer all questions in Section A. • Answer one question from Section B. • You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages. • If you need extra space for your answer(s), use the lined pages at the end of this book. Write the question number against your answer(s). • Show all your working. • Do all rough work in this book. Cross through any work you do not want For Examiner’s Use Question Mark 1 2 3 4 5 6 7 TOTAL to be marked. Information • The marks for the questions are shown in brackets. • The maximum mark for this paper is 78. 2 Section A Answer all questions in this section. You are advised to spend no more than 1 hour and 15 minutes on this section. 0 1 . 1 Describe how stimulation of a Pacinian corpuscle produces a generator potential. [3 marks] Scientists investigated the stimulation of a Pacinian corpuscle in the skin of a fingertip. The scientists applied two different pressures to the fingertip and recorded the changes in membrane potential of the Pacinian corpuscle’s sensory neurone. Figure 1 shows the scientists’ results. Figure 1 Do not write outside the box *02* IB/M/Jun23/7402/3 3 0 1 . 2Use Figure 1 to describe what is meant by the all-or-nothing principle. [2 marks] 0 1 . 3 On Figure 1, from 0.6 ms to 4.0 ms, no new generator potential could be produced. What is this time period called?