AQA A LEVEL BIOLOGY PAPER 2 QP 2023, Exams of Biology

Download AQA A LEVEL BIOLOGY PAPER 2 QP 2023 and more Exams Biology in PDF only on Docsity! 7402/2IB/M/Jun23/ E13 AQA A LEVEL BIOLOGY PAPER 2 QP 2023 7402/2IB/M/Jun23/ E13 A-level BIOLOG Y Paper 2 Friday 16 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.  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 to be marked. Information  The marks for the questions are shown in brackets.  The maximum mark for this paper is 91. For Examiner’s Use Questio n Mark 1 2 3 4 5 6 7 8 9 10 TOTAL Please write clearly in block capitals. Centre number Candidate number Surname Forename(s) Candidate signatu re 3 Do not write outside the *03 * IB/M/ Jun23/7402/2 1. Glutamate is a neurotransmitter involved in the transmission of nerve impulses from pain receptors to the brain. Ziconotide is a drug that can reduce severe, constant pain. Ziconotide blocks the calcium ion channels at some of the synapses which use glutamate. The transmission of glutamate at synapses is similar to that of acetylcholine. box Explain how ziconotide reduces severe, constant pain. [5 marks] Ziconotide is a polypeptide and acts on synapses in the spinal cord. Scientists investigated the effectiveness of ziconotide in reducing severe, constant pain. Ziconotide was injected into each patient’s cerebrospinal fluid that bathes the brain and spinal cord. Patients recorded the intensity of their pain using a statistically valid scale. 0 2 . 2 Suggest two reasons why the patients had ziconotide injected into their cerebrospinal fluid rather than taking a pill containing the drug. [2 marks] 1 2 Question 2 continues on the next page Turn over ► 20 4 Do not write outside the *04 * IB/M/ Jun23/7402/2 3. Ziconotide was injected at 3 ng kg–1 h–1 for 8 days into each patient. 1 ng = 1 × 10–9 g Calculate the total mass in grams of ziconotide injected after 8 days into a patient with a body mass of 82 kg box Show your working. [2 marks] Answer g 0 2 . 4 When the patients recorded the intensity of pain, suggest two reasons why it was important to use a statistically valid scale. [2 marks] 1 2 20 11 5 Do not write outside the *05 * IB/M/ Jun23/7402/2 1 Figure 1 shows part of a phosphorus cycle, including the mass of phosphorus in two stores. Figure 1 One teragram (Tg) is 1 × 1012 grams. The supply of phosphorus to the soil is shown as a percentage of the total phosphorus mass of each store. box . Calculate in teragrams the difference in the supply of phosphorus to the soil from the two stores shown in Figure 1. Show your working. [2 marks] Answer Tg Question 3 continues on the next page Turn over ► 30 0 3 8 Do not write outside the IB/M/ Jun23/7402/2 *0 * 0 3 . 3 The tomato seeds were planted into sterilised soil. Suggest two reasons why the soil was sterilised. [2 marks] 1 2 0 3 . 4 The soil used in this investigation had the recommended concentration of fertiliser. Suggest two reasons why the soil contained the recommended concentration of fertiliser. [2 marks] 1 2 9 Do not write outside the IB/M/ Jun23/7402/2 box 11 1 0 Do not write outside the *09 * IB/M/ Jun23/7402/2 Turn over for the next question DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED box Turn over ► 13 Do not write outside the *13* IB/M/ Jun23/7402/2 1. Figure 3 shows the wavelengths of light absorbed by three types of photoreceptor found in the human retina. Figure 3 Use Figure 3 and your knowledge of colour vision to explain how an orange colour is seen at 600 nm box [3 marks] 50 14 Do not write outside the *14* IB/M/ Jun23/7402/2 2. Which of the following statements is associated with high sensitivity to light in the retina? box Tick () one box. [1 mark] A single photoreceptor connecting to one neurone and spatial summation A single photoreceptor connecting to one neurone and temporal summation Several photoreceptors connecting to one neurone and spatial summation Several photoreceptors connecting to one neurone and temporal summation Question 5 continues on the next page 50 15 Do not write outside the *15* IB/M/ Jun23/7402/2 Turn over ► 18 Do not write outside the box *18* IB/M/ Jun23/7402/2 2 3 0 6 . 1 Describe and explain how three features of the cells in the proximal convoluted tubule allow the rapid reabsorption of glucose into the blood. [3 marks] 1 2 3 . Antidiuretic hormone (ADH) binds to V receptors found in cell-surface membranes in two parts of a nephron. Name the two parts of a nephron where V receptors are found. [1 mark] . V receptors only bind with ADH. Suggest and explain why. [2 marks] 60 60 19 Do not write outside the box IB/M/ Jun23/7402/2 0 6 . 4 A decrease in blood pressure stimulates the release of ADH. Give the location of the receptors that detect a decrease in blood pressure and explain how the release of ADH will affect blood pressure. [3 marks] Location Explanation Turn over for the next question *17* 9 20 Do not write outside the box IB/M/ Jun23/7402/2 Turn over ► 23 Do not write outside the *23* IB/M/ Jun23/7402/2 Turn over for the next question DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED box Turn over ► 24 Do not write outside the *24* IB/M/ Jun23/7402/2 1 2 . The KRAS gene codes for a protein called K-Ras. The protein relays signals from outside a cell to a cell’s nucleus, stimulating cell division. An alteration in the KRAS gene produces an oncogene which can cause a tumour to develop. Suggest and explain how an alteration in the KRAS gene can cause a tumour to develop. box [3 marks] . Alterations in the KRAS gene can cause colorectal cancer (CRC). Scientists investigated the survival time of the following three groups of CRC patients who had type II diabetes. Group A – received no drug to treat type II diabetes Group B – received the drug metformin to treat type II diabetes Group C – received a combination of drugs (including metformin) to treat type II diabetes The scientists used a statistical test to compare the survival time of these patients with CRC patients with no history of type II diabetes. 80 80 25 Do not write outside the *25* IB/M/ Jun23/7402/2 Table 1 shows some of the results obtained by the scientists. Table 1 Group Mean survival time of CRC patients / months Probability value (P) No history of type II diabetes 32.2 – A 21.3 0.007 B 49.7 0.022 C 38.3 0.636 Using the information provided, what can you conclude about the effects of type II diabetes and the different drug treatments on the survival time of CRC patients? [5 marks] box Turn over for the next question Turn over ► 8 28 Do not write outside the *28* IB/M/ Jun23/7402/2 Turn over ► 29 Do not write outside the *29* IB/M/ Jun23/7402/2 1 2 box . ATP is essential for muscle contraction (line 1). Describe the roles of ATP in muscle contraction. [2 marks] . Calculate how long maximum exercise would last if ATP was not resynthesised (lines 3–4). [1 mark] Answer s 01 01 1 0 Read the following passage. ATP is essential for muscle contraction. The concentration of ATP in skeletal muscle is approximately 5 × 10–3 mmol g–1. During maximum exercise, ATP in skeletal muscle is used at a rate of approximately 3.7 mmol kg–1 s–1. If ATP was not resynthesised, maximum exercise would last a short time. Some studies have suggested that taking creatine supplements can improve muscle performance during intense short-term exercise. Eating more carbohydrate, known as ‘carbohydrate loading’, for a few days before exercise can improve muscle performance when exercising for a long time. During aerobic exercise, calcium ions in muscle cells have several roles. They activate the inclusion of glucose transport proteins, GLUT4, in the cell-surface membrane and the inclusion of fatty acid transport proteins, CD36, in mitochondrial membranes. An increase in muscle activity increases the concentration of carbon dioxide in the blood. 5 10 30 Do not write outside the *30* IB/M/ Jun23/7402/2 3. Describe and explain how taking creatine supplements (lines 5–6) and ‘carbohydrate loading’ (lines 6–7) can improve performance of different types of muscle fibres during different types of exercise. box [5 marks] Question 10 continues on the next page Turn over ► 01 33 Do not write outside the box IB/M/ Jun23/7402/2 Questio n number Additional page, if required. Write the question numbers in the left-hand margin. *2 * 34 Do not write outside the box IB/M/ Jun23/7402/2 35 Do not write outside the box *35* IB/M/ Jun23/7402/2 Questio n number Additional page, if required. Write the question numbers in the left-hand margin.