9700 · June 2024
Biology
Questions 6, 10, 11, 18, 23, 25, 30, 31 and 39 focused on knowledge and understanding and were found to be relatively straightforward. Questio Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Principal Examiner Report for Teachers
Source: Cambridge International
Cohort performance
Session statistics from official examination reports
No data available in official reports
Key examiner messages
Top priorities from the principal examiner before you revise
Candidates should take care when writing units; in Question 1(a)(i), nm often looked like m.
Writing the full compound unit in descriptions of the rate of transpiration in Question 5(a) gave many candidates problems as they did not write out the unit in full as mmol m−2 s−1.
There were several questions on this paper that required candidates to make comparisons.
In Question 2(c)(ii), the structure of a muscular artery had to be compared with the structure of an arteriole visible in the transmission electron micrograph of a cross-section of an arteriole.
Question 5(a) asked candidates to compare transpiration rates of two plants shown in a graph.
These questions did not specifically ask for similarities and/or differences and so candidates were free to give similarities and differences that could be credited.
Acceptable acronyms DNA, RNA and ATP are given in the AS syllabus and may be used instead of the longer full names of these molecules.
For other scientific terms, candidates should write out the full term the first time they use it, to show that they have the correct knowledge of the term, before they shorten it by using an acronym, abbreviation or symbol.
Question difficulty map
How candidates performed on each question in this series
9700/11
Multiple Choice
9700/12
Multiple Choice
9700/13
Multiple Choice
9700/21
AS Level Structured Questions
9700/22
AS Level Structured Questions
9700/23
AS Level Structured Questions
Assessment objectives
Skill and AO weighting from official examiner commentary
No data available in official reports
Method marks watchlist
Where working, steps, or method marks were commonly lost
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Recurring mistakes across years
Themes examiners flag in multiple recent sessions for this subject
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Question choice intelligence
Mean scores and popularity for optional questions (HKDSE electives)
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Level exemplars
What candidate scripts at each grade level looked like
No data available in official reports
Grade & admission context
How marks relate to grade thresholds and entry standards
No data available in official reports
Deep insights
What top candidates did
Techniques and approaches examiners rewarded in this series
Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Prin…
Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Principal Examiner Report for Teachers © 2024 Question 5 About one fifth of the cohort selected the correct option, D (four hydrogen bonds), with slightly more candidates suggesting that there was a maximum of two hydrogen bonds (option B) between a single water molecule and other water molecules. This question required candidates to think about the three-dimensional structure of a water molecule in the liquid state, where one hydrogen bond can form between each of its hydrogen atoms and other water molecules, and two other water molecules can form hydrogen bonds with the two lone pairs associated with its oxygen atom. Question 9 Slightly more candidates calculated the correct mass of haemoglobin from the data as 64.5 kDa (option D) than those who incorrectly calculated it as 31.6 kDa (option A). Candidates who chose option A thought that there was only one each of the –globin chain, –globin chain and the haem group in a haemoglobin molecule. Very few candidates who had accounted for both –globin and –globin chains made the error of only adding one haem group in their calculation (option C). Question 13 Many candidates found this applied question on the cotransporter mechanism difficult. Candidates were required to compare their knowledge of the cotransporter mechanism in phloem with a diagram of a cotransporter moving nicotine and protons in and out of the blood plasma. Although slightly more candidates opted for the correct answer, option B, similar numbers of candidates selected each of the three other options. Question 15 This question on osmosis required candidates to apply their knowledge in a practical context to the observations of two microscope slides that contained some blood cells and different concentrations of salt. Approximately half the cohort correctly identified the explanations for the results on the two microscope slides (option B), with no clear pattern in the incorrect options selected by the other candidates. Question 17 Although most candidates knew that stems cells can give rise to phagocytes, only half of the candidates also realised that stem cells cannot repair cells (option D). Any damaged cells would need to be replaced. Question 27 This challenging question required candidates to identify two points on a graph of the volume in the ventricles during the cardiac cycle and connect this information with the opening and closing of the valves. Slightly more candidates selected the correct option (A) than chose the next most popular options, B or C. Very few candidates suggested that both valves would be open at the transitions between the systole and diastole (option D). Question 33 Almost all candidates knew that a continual supply of deoxygenated blood by the pulmonary artery helps to maintain the concentration gradient of gases in the lungs. Slightly more candidates incorrectly suggested that the recoil of elastic fibres in the walls of the alveoli is not involved (option B), than correctly attributed this mechanism to the maintenance of the gradient (option A).
Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Prin…
Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Principal Examiner Report for Teachers © 2024 Comments on specific questions Question 1 (a) (i) The most popular answer for the thickness of the membrane in Fig. 1.1 was 7 nm. Any answer between 5 nm and 10 nm was accepted, as were ranges of measurements, such as 6–8 nm. Some candidates gave 7 but followed it with the wrong unit, usually m. (ii) Many candidates completed Table 1.1 correctly, often with considerable detail. When facilitated diffusion was not given as the answer to row 1 there was often a suitable description of the process. Many candidates chose C rather than A in the first row: C is a carrier protein, not a channel protein. The simplest answer for the phospholipids in row 2 was ‘forms a bilayer’, and many referred to their role in forming a barrier to the movement of water-soluble substances. Glycoproteins and glycolipids were accepted for the receptor for cell signalling. Some candidates gave B and D in the final column for the receptor. This was accepted if both glycoprotein and glycolipid were given in the first column in the same order. Common answers for cholesterol in row 4 were providing stability and maintaining fluidity of the membrane. Many also stated that cholesterol regulates or maintains ‘cell fluidity’. Many described the phospholipid molecule rather than describing its function in the cell surface membrane. (b) (i) Many candidates drew recognisable drawings of the three organelles. Errors included: showing ribosomes inside the cisternae of the rough endoplasmic reticulum or across the membrane; drawing a mitochondrion with three membranes, not two; and showing the cisternae of both rough endoplasmic reticulum and smooth endoplasmic reticulum as single lines. Some labelled one of the drawings of chloroplasts as a mitochondrion instead of following the instruction to draw the organelle. (ii) Most candidates correctly gave the answer as Golgi body. ‘Golgi’ on its own did not gain credit, but Golgi apparatus or Golgi complex was acceptable. There were many good answers for the function of this organelle, including glycosylation of proteins. Quite a few gave the incorrect answer ‘protein synthesis’ as the function. Question 2 (a) This question focused on two properties of water that make it suitable as the main component of blood. Most candidates stated that water is a good solvent and listed some of the substances that are transported in solution in the blood, such as glucose, albumen, and hydrogencarbonate ions. Some candidates only stated that water was a solvent and could gain credit if they explained that ions and polar molecules are dissolved in water. A few gave an example of a substance transported in solution in the plasma and linked it with a reason. The other property that is relevant to blood is the high specific heat capacity of water. Many related this to the importance of maintaining the constant temperature of the blood. Credit was not given to those who omitted ‘specific’ and only stated that water has a ‘high heat capacity’. It was not relevant in this question to refer to the latent heat of vaporisation. Some candidates wrote about cohesion and adhesion, which is relevant to transport in the transpiration stream, but not in the blood stream. (b) (i) Most candidates stated the aorta for P and the vena cava for Q and most spelled these correctly. Venae cavae was also accepted. The most common error was to label P as pulmonary artery and Q as pulmonary vein. (ii) Most candidates stated that the aorta (P) carries oxygenated blood to the organs or to the body. It was taken that this referred to the systemic circulation and did not include the lungs, although it is ideal for candidates to write ‘to the body except to the lungs’. Most stated that the vena cava (Q) carries deoxygenated blood to the heart. Candidates who referred to the blood pressure in these vessels rather than to the degree of oxygenation gained credit. Candidates should be aware that arteries and veins do not pump blood. (iii) The great majority of candidates gained full credit by explaining why the mammalian circulation is described as a closed, double circulation. Some lost credit by writing simply ‘blood flows through the heart twice’ without further qualification that this happens in each circulation or circuit of the body.
Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Prin…
Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Principal Examiner Report for Teachers © 2024 (ii) There were many good descriptions of the role of the ciliated epithelium in protecting the gas exchange system from particulate matter, including pathogens. Good answers explained that goblet cells secrete mucus and that this covers the ciliated epithelium to trap material such as dust, pollen, bacteria and viruses. The function of ciliated epithelial cells was described as possessing cilia to move mucus towards the throat or mouth. The direction taken by the mucus was often described as ‘upwards’ and this was accepted. Fewer showed an understanding that, to protect all cells and prevent pathogens reaching cells, mucus covers the epithelium to trap pathogens. Some wrote that mucus prevented pathogens reaching the gas exchange system, forgetting that the ciliated epithelium shown in Fig. 4.1 is in the gas exchange system. Many wrote that the cilia move pathogens and omitted to state that cilia move the mucus with trapped material. Weak responses stated that cilia provide a large surface area for gas exchange. (b) (i) Many stated that the internal appearance of structure X, a cilium, is a 9+2 arrangement of microtubules. Some of these gave a comprehensive account by including further detail. Weaker responses suggested that cilia are made of microfilaments rather than microtubules. (ii) The answer, clearly visible in Fig. 4.2, is that each cilium is surrounded by a cell surface membrane. Many candidates needed to look more carefully at the transmission electron micrograph (TEM) of cross sections of the cilia from the surface of the epithelial cell. A number of candidates stated that the structures were surrounded by a membrane or double membrane, rather than the cell surface membrane, or simply suggested that they were inside a cell. Some candidates attempted to justify their answer in terms of the magnification of Fig. 4.2 or just wrote about the magnification of the image in the TEM. (c) Good answers to this question described the function of centrioles in mitosis. These answers often began by stating that centrioles organise microtubules into spindle fibres for the movement of chromosomes. The term microtubular (or microtubule) organising centre (MTOC) was frequently seen. Candidates also described the replication or duplication of centrioles during the S phase and/or G2 phase of the cell cycle and their movement to the poles during prophase. Imprecise descriptions of moving to ‘opposite sides of the cell’ were infrequently seen. There were a few descriptions of named stages and the process of microtubules being assembled to lengthen spindle fibres or disassembled to shorten the fibres. Movement of chromosomes during mitosis was frequently included in responses, but this was not relevant to the question posed. Question 5 (a) Fig. 5.1 showed the transpiration rates of two plants. As in Question 2(c)(ii), credit was available for identifying similarities and differences, in this case between the results for the two species. It was clear that some candidates had used a ruler to help them analyse the graph and take appropriate data points to illustrate their answer. Other candidates simply gave a list of transpiration rates for the two species without making any descriptive comments. Very few candidates stated that there was no transpiration in either species when the leaf vapour pressure deficit (LVPD) was 0 kPa. Many stated that the rates of transpiration increased as LVPD increased. However, some of these went on to state that both species reached a point at 2.5 kPa when the rate remained constant, or reached a plateau, when clearly this only applied to Helianthus annuus. A number of candidates were more precise and stated that the rate of transpiration for Nerium oleander decreases slightly at 3.0 kPa. Many also stated that the rate of transpiration of Helianthus annuus is higher at all values of LVDP, and a high proportion of these gave a comparative data quote in support. Many also noted the steeper gradient for H. annuus. Some candidates could have gained more credit by using units with numerical data or by writing the unit for rate of transpiration in full. When writing the units some candidates included the solidus, which was not necessary. Some candidates wrote about Vmax and Km. These are appropriate for a graph showing rates of enzyme action at different concentrations of substrate, not for a graph of transpiration rates. (b) In the information at the start of Question 5, candidates were told that N. oleander was adapted to grow in hot, dry conditions. In this question, candidates were able to deduce that the leaf of Nerium would have xerophytic adaptations so that rates of transpiration would be reduced. To gain full credit, the stated adaptation identified in Fig. 5.3 and then in Fig. 5.4, had to be accompanied by a suitable explanation in terms of reducing water vapour loss from the leaves. The most common adaptation noticed by the candidates in Fig. 5.3 was the location of stomata in cavities or
Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Prin…
Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Principal Examiner Report for Teachers © 2024 chambers on the lower surface of the leaf. There were other acceptable descriptions for this stated adaptation. For Fig. 5.4 candidates noticed the thick cuticle and the presence of trichomes. A common error was to state that the stoma in Fig. 5.4 was sunken. This was only accepted for Fig. 5.3 where stomata can be seen in the cavity on the lower surface. Some candidates thought the trichomes were root hairs and others referred to a waxy cuticle without qualifying their answer with the word ‘thick’. Question 6 (a) (i) Many were able to explain how the structure of antibodies makes the antigen-binding sites specific for a particular antigen by writing about the complementary shapes of the antigen and antibody binding site. The strongest responses also drew on knowledge of the levels of organisation of proteins. They made accurate references to the sequence of amino acids and/or to the folding to form secondary and tertiary structures of the variable regions, with some explaining the effect of the specific R groups that form the binding sites. Some candidates misused the term epitope, which is not a term that is required knowledge, to refer to the antibody instead of the antigen. (ii) Many candidates stated that the hinge region provides flexibility but did not continue their answer to say why this is an advantage. Strong answers stated that it gives the flexibility to bind to antigens that are various distances apart on the surface of a pathogen. A common answer that did not gain credit was ‘to hold the polypeptide chains together’. (iii) A number of candidates were able to suggest an appropriate advantage of having antibodies binding to receptors on macrophages. These receptors are for the constant regions of antibodies and so facilitate the binding of a macrophage to a pathogen that already has antibodies bound to its surface. Many others stated that this was related to antigen presentation or to the activation of T-lymphocytes. Some candidates’ answers could have been made clearer if they had sketched a diagram of an antibody bound at one end to a receptor on a macrophage and at the other end to an antigen on a pathogen. (b) This question relied on an understanding of RNA splicing during post-transcriptional modification. Many candidates included removal of introns in their answers, but most of these then stated that exons would be joined together. A number explained that to form the great variety of antibodies the exons could be joined in different orders or that some of the exons are not used at all. A few mentioned alternative splicing, which is the name for the process that produces variation in proteins at this stage in their production. A common incorrect answer was mutation, and some candidates referred to changes that occur after translation, not after transcription.
Command word playbook
How to match each command word to the expected response style
No data available in official reports
Time traps
Sections where candidates spent disproportionate time relative to marks
No data available in official reports
Syllabus traceability
Topics linked to questions and mark weighting in this session
No data available in official reports
MCQ trap analytics
Commonly chosen wrong options from examiner commentary
No data available in official reports
Topic heatmap across years
Mark concentration by topic and exam year for this subject
Mark intensity
Transport in plants (Biology (AS Level))
Cell membranes and transport (Biology (AS Level))
Homeostasis in mammals (Homeostasis)
Selection and evolution (Biology (A Level))
Enzymes
Classification, biodiversity and conservation
Cells as the basic units of living organisms (Cell structure)
Enzymes (Biology (AS Level))
Difficulty trend
How session difficulty has shifted across recent years
Paper comparison
Marks and duration breakdown across papers in this session
No data available in official reports
Marks you can still earn
Where valid approaches outside the mark scheme may still gain credit
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Practise what examiners flagged
Target weak topics from this report inside the Revui app
Self-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
Candidates should take care when writing units; in Question 1(a)(i), nm often looked like m.
- 2Message
Writing the full compound unit in descriptions of the rate of transpiration in Question 5(a) gave many candidates problems as they did not write out the unit in full as mmol m−2 s−1.
- 3Message
There were several questions on this paper that required candidates to make comparisons.
- 4Message
In Question 2(c)(ii), the structure of a muscular artery had to be compared with the structure of an arteriole visible in the transmission electron micrograph of a cross-section of an arteriole.
- 5Message
Question 5(a) asked candidates to compare transpiration rates of two plants shown in a graph.
- 6Message
These questions did not specifically ask for similarities and/or differences and so candidates were free to give similarities and differences that could be credited.
- 7Message
Acceptable acronyms DNA, RNA and ATP are given in the AS syllabus and may be used instead of the longer full names of these molecules.
- 8Message
For other scientific terms, candidates should write out the full term the first time they use it, to show that they have the correct knowledge of the term, before they shorten it by using an acronym, abbreviation or symbol.
- 9Strength
Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Prin…: Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Principal Exam
- 10Strength
Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Prin…: Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Principal Exam
- 11Strength
Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Prin…: Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Principal Exam
Teacher briefing pack
One-page session summary for tutors and classroom review
June 2024 2024
Biology
Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Principal Examiner Report for Teachers © 2024 BIOLOGY Paper 9700/11 Multiple Choice Question Number Key Question Number Key Question Number Key Question Number Key 1 A 11 C 21 C 31 D 2 B 12 D 22
Candidates should take care when writing units; in Question 1(a)(i), nm often looked like m.
Writing the full compound unit in descriptions of the rate of transpiration in Question 5(a) gave many candidates problems as they did not write out the unit in full as mmol m−2 s−1.
There were several questions on this paper that required candidates to make comparisons.
Examiner insights
General comments
- •Questions 6, 10, 11, 18, 23, 25, 30, 31 and 39 focused on knowledge and understanding and were found to be relatively straightforward.
- •Questio Cambridge International Advanced Subsidiary and Advanced Level 9700 Biology June 2024 Principal Examiner Report for Teachers