A-level BIOLOGY

A-level BIOLOGY Paper 3 Wednesday 19 June 2024 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 to be marked. Information • The marks for the questions are shown in brackets. • The maximum mark for this paper is 78. Section A Answer all questions in this section. You are advised to spend no more than 1 hour and 15 minutes on this section. box 0 1 . 1 In the following passage, each numbered space can be filled with a biological term. Each type of cell has specific molecules on its (1) that identify it. An antibody is a (2) with two (3) binding sites. Antibodies are made and released by (4) cells. Vaccines can provide protection for individuals and populations against disease. The response to a vaccine is an example of (5) immunity. (6) immunity occurs when a large proportion of a population becomes immune to a disease. Write the correct biological term beside each number below that matches the space in the passage. [3 marks] 1 2 3 4 5 6 0 1 . 2 There is currently no effective vaccine available for HIV. Suggest one reason why. [1 mark] . Table 1 shows the action of two antibiotics. Table 1 Antibiotic Action of antibiotic Ciprofloxacin Causes double-stranded DNA to break apart Penicillin Prevents formation of crosslinks between murein chains Using the information in Table 1, explain why each antibiotic is not effective against HIV. box [2 marks] Ciprofloxacin Penicillin Turn over for the next question Turn over ► 0 2 A student investigated the effect of temperature on the rate of aerobic respiration in woodlice. Figure 1 shows the apparatus they used. Figure 1 The student altered the temperature of the water bath and measured how far the drop of coloured liquid moved every minute for 5 minutes. 0 2 . 1 Other than those stated, suggest two variables the student should have kept constant in this investigation. [1 mark] 1 2 0 2 . 2 Describe how the student used the apparatus in Figure 1 to reset the drop of coloured liquid back to the right-hand end of the tubing. [2 marks] 0 2 . 3 The student also set up a control experiment. Suggest a suitable control experiment and explain why it was necessary. [2 marks] Control experiment Explanation Question 2 continues on the next page Turn over ► 0 3 . 1 Describe and explain the relationship between surface area to volume ratio of the human body and metabolic rate. [3 marks] Question 3 continues on the next page Turn over ► Table 2 shows the height and mass of two adults. Table 2 Person Height / cm Mass / kg A 181 90.90 B 149 62.62 The surface area of a person is estimated using the following formula: Surface area in m2 = �height in cm × mass in kg box The volume of a person is estimated using the following formula: Volume in m3 = mass in kg 0 3 . 2 Using suitable calculations, deduce which person has the smaller surface area to volume ratio. Show your working and complete the sentence below. Give your answer to 3 significant figures. [3 marks] Person has the smaller surface area to volume ratio which = 0 3 . 3 Which is not a possible explanation for the difference in surface area to volume ratio between person A and person B? Tick () one box. [1 mark] Person A and person B have different body shapes. Person A has a higher mass than person B. Person A is taller than person B. 0 3 . 4 Name two structural features of the gills of a fish that increase their surface area. [1 mark] 1 2 Turn over for the next question