Skip to main content
A-LevelBiologyCell membranes and transportOct/Nov 2017Paper 2 Q419 Marks

Fig. 4.1 is a transmission electron micrograph of the bacterium that causes cholera, Vibrio cholerae. The flagellum shown in Fig. 4.1 allows movement of the bacterium within the gut and may also function to help it to bind to an intestinal epithelial cell. The organism does not enter the cell but the toxin it releases can enter and cause damage. Large quantities of water, chloride ions and sodium ions are lost from the cell. People with symptoms of cholera have severe watery diarrhoea and as a result can become very dehydrated. [Figure 4.1]

📋 Examiner Report & Trap Analysis

Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...

🎯 Mark Scheme Breakdown

Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.

🔒

Unlock the Examiner's Analysis

Sign up for free to reveal the full examiner report, trap analysis, and mark scheme breakdown for this question.

Sign Up Free to Unlock →

Join thousands of Cambridge students already using Oracle Prep

About This A-Level Biology Question

Topic

This structured question tests Cell membranes and transport in A-Level Biology (syllabus code 9700). It is worth 19 marks.

Source

This question appeared in the Cambridge A-Level Biology Oct/Nov 2017 examination, Paper 2 Variant 2.

Practice on Oracle Prep

Oracle Prep provides AI-powered practice for all Cambridge O-Level and A-Level subjects. Our platform includes topic predictions with 87.7% accuracy, AI essay grading, and a comprehensive question bank spanning 25 years of past papers across 29 subjects.

Related Biology Questions

© 2026 Oracle Prep — The AI-Powered Cambridge Exam Engine