AQA A LEVEL BIOLOGY 7402/3 PAPER 3 QUESTION PAPER & MARK SCHEME {[VERIFIED]}, Exams of Biology

Download AQA A LEVEL BIOLOGY 7402/3 PAPER 3 QUESTION PAPER & MARK SCHEME {[VERIFIED]} and more Exams Biology in PDF only on Docsity! AQA A LEVEL BIOLOGY 7402/3 PAPER 3 QUESTION PAPER AND MARK SCHEME { MERGED} JUNE 2023 COMPLETE AND VERIFIED Centre number Candidate numberSurname Forename(s) Candidate signature I declare this is my own work. A- level Please write clearly in block capitals. 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 to be marked. Information • The marks for the questions are shown in brackets. • The maximum mark for this paper is 78. For Examiner’s Use Questio n Mark 1 2 3 4 5 6 7 TOTAL 3 Do not write *02* IB/M/Jun23/7402/3 6 4 Do not write outside the 1 .0 1 .0 2Use Figure 1 to describe what is meant by the all-or-nothing principle. [2 marks] box 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? [1 mark] Turn over for the next question *03 * Turn over ► IB/MjJ un23/7 402/3 Do not write ‘outside the 8 Do not write outside the 2 .0 Figure 3 shows the result she obtained for yeast in glucose solution. Figure 3 box 2 Use Figure 2 and Figure 3 to calculate the rate of carbon dioxide production in mm s–1 for yeast in glucose solution. Give your answer in standard form and to 2 significant figures. Show your working. [2 marks] Answer mm s–1 *05 * 9 Do not write outside the Turn over ► IB/M/Jun23/7402/3 2 .0 10 Do not write outside the 2 .0 3 The student repeated the experiment using yeast in maltose solution. She found the rate of carbon dioxide production was slower than with yeast in glucose solution. Suggest why. box [2 marks] 4 A second student used a different method to investigate the effect of different sugars on the rate of respiration in yeast. He set up a tube with yeast in glucose solution and added bromothymol blue. Bromothymol blue changes from blue to yellow when carbon dioxide is produced. To determine the rate of respiration, he timed how long it took for the solution to change from blue to yellow. Suggest: • why the method the second student used would be less accurate than the method the first student used • how the accuracy of the method the second student used could be improved. [2 marks] This method would be less accurate because The accuracy of this method could be improved by *06* 13 NAD carbon dioxide acetate IB/MjJ un23/7402/3| a Do not write ‘outside the ). He 3 .0 14 Do not write outside the 1 Below are four statements about the structure of prokaryotic cells. 1. No prokaryotic cell has DNA that is associated with proteins. 2. No prokaryotic cell has membrane-bound organelles. 3. All prokaryotic cells have one or more flagella. 4. All prokaryotic cells have smaller ribosomes than eukaryotic cells. Which statements about the structure of prokaryotic cells are correct? Tick (✓) one box. [1 mark] box A statements 1, 2 and 3 B statements 1, 2 and 4 C statements 2, 3 and 4 D statements 1, 2, 3 and 4 A student investigated the effect of two antibiotics on the growth of the bacterium Micrococcus luteus. During the investigation, the student: 3• transferred 9 cm of a liquid culture of M. luteus into each of three bottles • added the antibiotic chloramphenicol to the first bottle • added the antibiotic novobiocin to the second bottle • added no antibiotic to the third bottle. After 24 hours, he diluted the contents of each bottle by 1 in 100 000 (10– 5 transferred 0.25 cm3 samples from the first bottle onto each of 3 separate agar plates.3 He repeated this with 0.25 cm samples from the second bottle and the third bottle, resulting in 9 agar plates in total. He incubated the plates for 48 hours. Table 1 shows the number of colonies of bacteria he counted on each plate after 48 hours’ incubation. 15 Do not write outside the *08* IB/M/Jun23/7402/3 18 *11 * Turn over for the next question DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED 19 Do not write outside the box T u r n over ► IB/M/Jun23/7402/3 20 4Fo0 llowing a body injury, bone marrow stem cells move to the site of damage and undergo cell differentiation. Figure 5 shows how this differentiation occurs. Figure 5 Do not write outside the box A gene called A stem cell TK After the cell c-KIT codes for factor (SCF) phosphorylates has stem cell binds to SCFR cell signalling differentiated, growth factor and activates molecules to SCFR is receptor tyrosine kinase begin cell enclosed within protein (SCFR) (TK) differentiation a vesicle and on the surface destroyed by a membrane of lysosome the stem cell 0 4 . 1 Suggest how SCFR is destroyed by a lysosome. [2 marks] After a heart attack, cardiomyocytes (cardiac muscle cells) die, and become infarcted tissue. Infarcted tissue cannot contract. Stem cells in bone marrow cannot move to the infarcted tissue and differentiate into cardiomyocytes. Scientists used laboratory rats to investigate if bone marrow stem cell transplants could be used to repair infarcted tissue resulting from a heart attack. They split the rats into three groups. • Control group did not get a transplant of bone marrow stem cells. • c-KIT+ group got a transplant of bone marrow stem cells with a functioning c-KIT gene. • c-KIT– group got a transplant of bone marrow stem cells with no functioning c-KIT gene. After 9 days, the scientists measured the mean ventricular blood pressure of each of the three groups. 23 IB/MjJ un23/7402/3 10 24 4 .0 0 4 . 3 Nine days after transplantation, the c-KIT+ group showed that 68% of infarcted tissue was made up of new cardiomyocytes. The control group had no new cardiomyocytes. Assuming that mean ventricular blood pressure is directly proportional to the number of cardiomyocytes, calculate the percentage of infarcted tissue that was made up of new cardiomyocytes in the c-KIT– group. Do not write outside the box [2 marks] Answer % All new cardiomyocytes produced: • Connexin-43, a channel protein that allows electrical impulses to pass between cardiomyocytes • GATA-4, a transcriptional factor that stimulates the expression of genes for actin and myosin. 4 Suggest how production of Connexin-43 and GATA-4 could give the result seen in the c- KIT+ group in Figure 6 (on page 13). Do not include details of transcription or translation in your answer. [2 marks] Connexin-43 GATA-4 *14* IB/M/Jun23/7402/3 25 *15 * Turn over for the next question DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED – 28 5 .0 0 5 . 1The scientists used the following formula to calculate the index of diversity (d) of fish. N(N 1) – where N = total number of fish of all species and n = total number of fish of each species Do not write outside the box In some years, the values were N = 624 and Σn (n–1) = 64 792 Which years had these values? Use Figure 8 and the formula above to work out your answer. [1 mark] Answer 2 In 1997, the scientists recorded the highest species richness, but the lowest value of d over the 29 years. Describe and explain how these results for 1997 were possible. [2 marks] Question 5 continues on the next page *17 * Turn over ► IB/M/Jun23/7402/3 7 29 5 .0 3 A journalist studied Figure 7 and Figure 8 (on page 16) and concluded that releasing heated water from a power station has no effect on local fish communities. Use all the information to suggest reasons why the journalist’s conclusion might not be valid. Do not write outside the box [4 marks] *18* IB/M/Jun23/7402/3 30 *19 * Turn over for the next question DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED 33 IB/M/Jun23/7402/3 34 6 .0 3 Plot a suitable graph for mean increase in ear thickness for each group of mice in Table 2. Include the data for ± 2 standard deviations on your graph. Do not write outside the box [3 marks] Question 6 continues on the next page *21 * Turn over ► 35 IB/M/Jun23/7402/3 38 IB/M/Jun23/7402/3 15 39 Do not write outside the 6 .0 6 In mice, one type of autoimmune disease is inherited as a dominant allele. Would the Hardy–Weinberg principle hold true for a population of mice, some of which had this autoimmune disease? Explain your answer. box [2 marks] *24* IB/M/Jun23/7402/3 40 Do not write outside the 7Wr0 70 7 .0 Section B Answer one question. You are advised to spend no more than 45 minutes on this section. box ite an essay on one of the topics below. Either . 1 The importance of interactions between organisms and their environment. [25 marks] Or *25 * 2 The importance of membranes in the functioning of cells. [25 marks] Turn over ► 43 D o n o t w ri t e o u t s i d e t h e b o x *27 * Turn over ► IB/M/Jun23/7402/3 28 Do not write outside the box *28* IB/M/Jun23/7402/3 30 Do not write outside the box *30* IB/M/Jun23/7402/3 31 D o n o t w ri t e o u t s i d e t h e b o x *31 * Turn over ► IB/M/Jun23/7402/3 *33 * Turn over ► IB/M/Jun23/7402/3 34 Do not write outside the box *34* IB/M/Jun23/7402/3 35 Do not write outside the box END OF QUESTIONS *35* IB/M/Jun23/7402/3 25 38 *38* Do not write outside the box IB/M/Jun23/7402/3 Question number Additional page, if required. Write the question numbers in the left-hand margin. 39 *39* Do not write outside the box IB/M/Jun23/7402/3 Question number Additional page, if required. Write the question numbers in the left-hand margin. 40 There are no questions printed on this page DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED Do not write outside the box MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 Mark scheme instructions to examiners 1. General The mark scheme for each question shows: • the marks available for each part of the question • the total marks available for the question • the typical answer or answers which are expected • extra information to help the examiner make his or her judgement and help to delineate what is acceptable or not worthy of credit or, in discursive answers, to give an overview of the area in which a mark or marks may be awarded. The extra information in the ‘Comments’ column is aligned to the appropriate answer in the left-hand part of the mark scheme and should only be applied to that item in the mark scheme. At the beginning of a part of a question a reminder may be given, for example: where consequential marking needs to be considered in a calculation; or the answer may be on the diagram or at a different place on the script. In general the right-hand side of the mark scheme is there to provide those extra details which confuse the main part of the mark scheme yet may be helpful in ensuring that marking is straightforward and consistent. 2. Emboldening In a list of acceptable answers where more than one mark is available ‘any two from’ is used, with the number of marks emboldened. Each of the following bullet points is a potential mark. A bold and is used to indicate that both parts of the answer are required to award the mark. Alternative answers acceptable for the same mark are indicated by the use of OR. Different terms in the mark scheme are shown by a / ; eg allow smooth / free movement. 3. Marking points Marking of lists This applies to questions requiring a set number of responses, but for which students have provided extra responses. The general principle to be followed in such a situation is that ‘right + wrong = wrong’. Each error / contradiction negates each correct response. So, if the number of errors / contradictions equals or exceeds the number of marks available for the question, no marks can be awarded. However, responses considered to be neutral (often prefaced by ‘Ignore’ in the ‘Comments’ column of the mark scheme) are not penalised. MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 3 MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 Marking procedure for calculations Full marks can be given for a correct numerical answer, without any working shown. However, if the answer is incorrect, mark(s) can usually be gained by correct substitution / working and this is shown in the ‘Comments’ column or by each stage of a longer calculation. Interpretation of ‘it’ Answers using the word ‘it’ should be given credit only if it is clear that the ‘it’ refers to the correct subject. Errors carried forward, consequential marking and arithmetic errors Allowances for errors carried forward are most likely to be restricted to calculation questions and should be shown by the abbreviation ECF or consequential in the mark scheme. An arithmetic error should be penalised for one mark only unless otherwise amplified in the mark scheme. Arithmetic errors may arise from a slip in a calculation or from an incorrect transfer of a numerical value from data given in a question. Phonetic spelling The phonetic spelling of correct scientific terminology should be credited unless there is a possible confusion with another technical term. Brackets (…..) are used to indicate information which is not essential for the mark to be awarded but is included to help the examiner identify the sense of the answer required. Ignore/Insufficient/Do not allow Ignore or insufficient is used when the information given is irrelevant to the question or not enough to gain the marking point. Any further correct amplification could gain the marking point. Do not allow means that this is a wrong answer which, even if the correct answer is given, will still mean that the mark is not awarded. MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 01.3 (The) refractory (period); Ignore any reference 1 to absolute or relative (AO1) Reject refraction period 5 MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 Question Marking Guidance Mark Comments 02.1 Accept any two of the following for one mark: Ignore number of yeast cells Ignore amount for Concentration/mass of yeast volume or Concentration/mass of glucose/sugar (solution/s) concentration Concentration of oxygen (in solution) 1 Volume of yeast (AO3) Volume of glucose/sugar (solution/s) pH (of glucose/sugar solution/s) Species/type of yeast Size/diameter/volume of test tubes Question Marking Guidance Mark Comments Correct answer of 2.5 x 10–2 = 2 marks;; 4.2 x –2 (scale read from the wrong direction)10 = 1 mark OR 2.5 x –3 (scale read as 3.7 mm not 3.7 cm)10 = 1 mark OR 2.4 x –2 (scale read as 36.5) = 1 mark10 OR Correct answer not in standard form and/or not to 2 significant figures, eg 0.0247/0.025/2.47 x 10–2 = 1 mark OR Answer in incorrect standard form eg 25 x 10–3 or 0.25 x 10–1 = 1 mark OR Evidence of 37 ÷ 1500 or 37 ÷ (25 x 60) = 1 mark 2 02.2 (2 x AO2) MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 6 MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 Question Marking Guidance Mark Comments 02.5 All 4 correct = 2 marks;; Accept pyruvic acid for Any 2 or 3 correct = 1 mark pyruvate For reduced NAD accept NADH, NADH + + or NADH2H For reduced NAD 2 reject reduced NADP / NADPH / NADPH2 / (2 x NADPH + H+ AO1) For acetylcoenzyme A accept acetyl co A MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 20238 MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 Question Marking Guidance Mark Comments 03.1 Second box ticked; 1 Answer key: B – (AO1 ) statements 1, 2 and 4 Question Marking Guidance Mark Comments 03.2 A correct answer of 9(.144) x 108 = 2 marks;; Answer not in standard form (914 400 000) = 1 mark OR Answer in incorrect standard form = 1 mark OR 2 1.016 × 8 (everything else correct except failed to10 (2 x multiply by 9) = 1 mark AO2) OR 2.286 × 8 (everything else correct but failed to 10 take the plating of 0.25 cm3 into account) = 1 mark OR 9.432 x 8 (discounted 238 as anomalous, all10 other calculations correct) = 1 mark MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 202310 Number of Standard Population generations form size 1 2 x 100 2 2 4 x 100 4 3 8 x 100 8 4 1.6 x 101 16 5 3.2 x 101 32 6 6.4 x 101 64 7 1.28 x 102 126 8 2.56 x 102 256 9 5.12 x 102 512 10 1.024 x 103 1024 11 2.048 x 103 2048 12 4.096 x 103 4096 13 8.192 x 103 8192 14 1.638 x 104 16384 15 3.277 x 104 32768 16 6.553 x 104 65536 17 1.311 x 105 131072 18 2.621 x 105 262144 19 5.243 x 105 524288 20 1.049 x 106 1048576 21 2.097 x 106 2097152 22 4.194 x 106 4194304 23 8.388 x 106 8388608 Number of Standard Population generations form size 24 1.678 x 107 16777216 25 3.355 x 107 33554432 26 6.711 x 107 67108864 27 1.342 x 108 134217728 28 2.684 x 108 268435456 29 5.369 x 108 536870912 30 1.073 x 109 1073741824 31 2.147 x 109 2147483648 32 4.295 x 109 4294967296 33 8.590 x 109 8589934592 34 1.718 x 1010 17179869184 35 3.436 x 1010 34359738368 36 6.872 x 1010 68719476736 37 1.374 x 1011 38 2.749 x 1011 39 5.498 x 1011 40 1.100 x 1012 41 2.199 x 1012 42 4.398 x 1012 43 8.796 x MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 Table 1 for question 03.3 11 MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 Question Marking Guidance Mark Comments 03.4 1. The concentration (of chloramphenicol) was too Accept as an low/dilute (to kill all) additional mark point 4. Chloramphenicol/ OR antibiotic not (evenly) mixed in There were too many M. luteus/bacteria for the liquid chloramphenicol/antibiotic to kill; 2 max culture/bottle (2 x 2. (Contamination with) other/resistant bacteria; AO3) 3. Mutation (occurred); MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 13 MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 Question Marking Guidance Mark Comments 04.2 Control 1. Cardiomyocytes/(cardiac muscle) cells have not been replaced OR Infarcted tissue is not repaired/replaced OR (The contraction of the ventricle is weak as) there is a small number of cardiomyocytes/ (cardiac muscle) cells still alive OR (The ventricular pressure is low as) cardiomyocytes/(cardiac muscle) cells are damaged/dead; 2. (Pressure is not zero as) not all cardiomyocytes/(cardiac muscle) cells died OR (Pressure is not zero as) not all cardiomyocytes/(cardiac muscle) cells became infarcted tissue; c-KIT– 3. Higher than control, so (some) stem cells (must) have been able to differentiate OR Higher than control, so (some) cardiomyocytes/(cardiac muscle) cells have been replaced/infarcted tissues have been repaired; 4. (So) c-KIT is not the only gene responsible for differentiation OR (So) SCF must be able to bind to something other than SCFR OR (So) something else must be able to activate TK in cells; 5. Increase is less than c-KIT+ group as they could not make SCFR OR 4 (4 x AO3) 1. Reject ‘some stem cells from bone marrow moved to the infarcted tissue’ Increase is less than c-KIT+ group as they could not activate TK; 14 MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 Question Marking Guidance Mark Comments 05.1 1982 and 2003; 1 (AO3) Reject if any other years are given Question Marking Guidance Mark Comments 05.2 1. There were many/48 (different) species OR (1997 had) the highest number of (different) species; 2. (However,) one/a few species were present in (very) large numbers OR Most species were present in (very) small numbers; 2 (2 x AO2 ) 1. Accept a lot/lots of (different) species for many 2. Accept dominated by one/a few species 2. Ignore each/all species were present in (very) small numbers 16 MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 Question Marking Guidance Mark Comments 05.3 1. The species richness/d are lower after 29 years; 2. The data is only for one (fish/local) community/site OR The data might not be representative of all fish communities OR Other communities might have different (fish) species; 3. (The measurements) only done in October OR The community might be different at other times of year (other than October); 4. The volume/temperature of the heated water (released each year) might have varied OR Timing/frequency of heated water release (each year) not known; 5. Fluctuations suggest other named factor had an effect (on biodiversity/species richness/d); 6. Species richness/d are not the only measures of ‘effect’; 7. Don’t know when the power station opened OR There is no data before 1980 OR There is no data before heated water was released 4 max (4 x AO3 ) 5. Named factors could include weather/oxygen concentration/fo od availability/plant s/ predators/prey/ insects/ invertebrates/ fishing OR No control (river) to compare with; 17 MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 Question Marking Guidance Mark Comments 06.3 1. Labelled axes correct way round, linear scale 1. Reject if line graph drawnand units; 1. Reject if Y-axis 2. Mean points plotted correctly; does not cover at least half of the 3. SD bars correctly plotted above and below the grid 1 . Reject if bars not peak of each bar; of equal width 3 1. Accept a dual bar (3 x chart drawn AO2) 1. Reject if bars are touching (except dual bars) 1. Accept interruption drawn on the y axis 2. and 3. Allow all plots to the nearest half cm MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 19 MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2023 Question Marking Guidance Mark Comments 06.4 Cellular response 1. Female to female no significant difference in cellular response as SD overlap; 2. Male to male no significant difference in cellular response as SD overlap; 3. Significant increase in cellular response in autoimmune male compared with autoimmune female as SD do not overlap Humoral response 4. Male to male no significant difference in humoral response as SD overlap; 5. Female to female significant increase in humoral response as SD do not overlap; 6. Significant increase in humoral response in autoimmune female compared with autoimmune male as SD do not overlap 3 max (3 x AO3 ) Max 2 for answers only relating to the cellular response or humoral response Accept ‘(ear) thickness’ for cellular response, and ‘concentration of anti-OXA/ antibody’ for humoral response If no other marks awarded, accept 1 principle mark for the idea that if SD overlap there is no significant difference or the converse 1. 2. and 4. Accept difference (likely) due to chance for no significant effect 3. 5. and 6. Accept increase not (likely) due to chance for significant increase Allow ‘error bars’ for ‘SD’