Fluid mosaic membranes: past paper questions
Real questions on fluid mosaic membranes
The newest 20 of 93 written questions. Open one to see it on the real paper.
- 9700/21 · October/November 2025 · Q1a[3]
A B (a) Name the structures labelled A, B and C in Fig. 1.1.
See it on the paper → - 9700/21 · October/November 2025 · Q1b[2]
Draw an arrow on Fig. 1.1 to show the movement of a molecule across the membrane into the cell by facilitated diffusion.
See it on the paper → - 9700/21 · October/November 2025 · Q1c[3]
Explain how the fluidity of the membrane would change if the proportion of unsaturated fatty acids in the phospholipid bilayer increased.
See it on the paper → - 9700/22 · October/November 2025 · Q4a[3]
With reference to Fig. 4.1, outline the similarities and differences between the outer membrane of a Gram‑negative bacterial cell and the cell surface membrane of a eukaryotic cell.
See it on the paper → - 9700/21 · May/June 2025 · Q4d[5]
T-vec is a new drug that has been developed to treat melanoma that has spread to other parts of the body, including lymph nodes. T-vec contains a virus that infects some of the melanoma cells, causing the cells to burst and release their contents. Some of the contents of the melanoma cells act as cytokines and others a...
See it on the paper → - 9700/23 · May/June 2025 · Q2d[4]
Cells that have been affected by melittin break down into cell fragments. These cell fragments are taken in by phagocytes for further breakdown. Describe the process by which phagocytes take in and break down these cell fragments.
See it on the paper → - 9700/23 · May/June 2025 · Q3c(i)[2]
Describe the role of goblet cells in the protection of tissues in the trachea from infection by S. aureus.
See it on the paper → - 9700/23 · May/June 2025 · Q6a[5]
Describe how monoclonal antibodies are produced using the hybridoma method.
See it on the paper → - 9700/42 · May/June 2025 · Q6a[4]
Describe the structure of guard cells.
See it on the paper → - 9700/42 · May/June 2025 · Q6b(i)[2]
With reference to Fig. 6.1, describe the rhythm of stomatal opening and closing.
See it on the paper → - 9700/42 · May/June 2025 · Q6b(ii)[2]
Suggest other environmental factors, apart from the time of day, that can contribute to stomatal closure.
See it on the paper → - 9700/42 · May/June 2025 · Q6c[4]
Table 6.1 shows some of the events occurring during the closure of a stoma. The events are not listed in the correct order. Table 6.1 description of event water leaves the guard cells by osmosis B active transport of hydrogen ions out of the guard cells stops C stoma closes D plant is subjected to a change in environme...
See it on the paper → - 9700/43 · May/June 2025 · Q1a[3]
the type of membrane transport protein represented by A process B (a) With reference to Fig. 1.1, name:
See it on the paper → - 9700/41 · October/November 2024 · Q1a(ii)[2]
The rat motor neurone has an impulse transmission speed of 50 m s –1 . The snail motor neurone has an impulse transmission speed of 8 m s –1 . Explain why the rat motor neurone has a faster impulse transmission speed than the snail motor neurone.
See it on the paper → - 9700/41 · October/November 2024 · Q1b[3]
Fig. 1.2 shows an action potential in a rat neurone and Fig. 1.3 shows an action potential in a snail neurone. rat 60 40 40 20 20 membrane 0 potential / mV −20 membrane 0 potential / mV −20 −40 −40 −60 −60 −80 0 5 15 10 snail 60 20 25 30 −80 0 5 time / ms 10 15 20 25 30 time / ms Fig. 1.2 Fig. 1.3 Contrast the two acti...
See it on the paper → - 9700/42 · October/November 2024 · Q8b[4]
Table 8.1 shows some of the events that occur during muscle contraction. They are not listed in the correct order. Table 8.1 event description of event A calcium ions diffuse out of sarcoplasmic reticulum B myosin heads bind to actin C sarcolemma depolarised D sarcomere shortens E calcium ions bind to troponin F T‑tubu...
See it on the paper → - 9700/42 · October/November 2024 · Q8c[4]
Lambert‑Eaton myasthenic syndrome (LEMS) is a rare disorder of the neuromuscular junction. A person with LEMS produces antibodies that bind to the voltage‑gated calcium channels on the presynaptic knob. One symptom of LEMS is weaker muscle contraction. Suggest and explain why LEMS leads to weaker muscle contraction.
See it on the paper → - 9700/21 · May/June 2024 · Q1a(i)[1]
State the approximate thickness of the membrane as shown by the line G–H.
See it on the paper → - 9700/21 · May/June 2024 · Q1a(ii)[4]
Complete Table 1.1 to show: • • the names and functions of the components of the cell surface membrane the letters of the labels in Fig. 1.1 that identify each component. Table 1.1 component function letter on Fig. 1.1 channel protein phospholipid receptor for cell signalling F
See it on the paper → - 9700/43 · May/June 2024 · Q1a[3]
Name structures A, B and C. A B C
See it on the paper →
What examiners said
Generally, there was a good understanding that cholesterol has a role in in regulating the fluidity of membranes. Responses of the highest standard linked this to the formation of vesicles for exocytosis. Some candidates misinterpreted the question and suggested that a reduction in cholesterol in the membrane would reduce synthesis of surfactant because this also contains cholesterol. Candidates n...
— Examiner report, October/November 2023, 9700/21 Q5(b)(ii) (Cambridge)
Some candidates made good suggestions as to why macrophages engulf surfactant. For example, a number suggested that macrophages were able to recycle the biological molecules in surfactant, releasing molecules such as cholesterol and proteins for reuse. The most common incorrect idea was to suggest that surfactant acts as a non-self antigen. Candidates who suggested that there were non-self antigen...
— Examiner report, October/November 2023, 9700/21 Q5(b)(iii) (Cambridge)
A number realised that this unfamiliar context of transport across membranes was an example of a protein carrier that functioned in the active transport of surfactant phospholipids across the membrane of the lamellar body. These candidates usually provided enough correct information to do well. The focus of assessment was knowledge of the features of proteins involved in active transport. Some rea...
— Examiner report, October/November 2023, 9700/22 Q4(c) (Cambridge)
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