A-LevelBiologyInfectious diseasesMay/June 2017Paper 2 Q611 Marks
Cholera bacteria release the toxin, choleragen, when they are in the intestine. (a) (i) Name the bacterium that is the pathogen of cholera. (ii) Describe the way in which cholera is transmitted from an infected person to an uninfected person. Gangliosides are glycolipids that bind choleragen. These glycolipids are found on many cell surface membranes. When choleragen is released from the bacteria in the intestine, it binds to gangliosides on epithelial cells and enters these cells as shown in Fig. 6.1. [Figure 6.1]
📋 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.
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