Practise IB Biology HL 3.2.1 by comparing pathogen transmission and disease mechanisms using cholera, malaria and intracellular infection examples.
Outline the symptoms, mode of transmission and treatment of one named example of food poisoning.
symptom;
transmission;
treatment;
eg Salmonella food poisoning
symptoms: diarrhoea/fever/abdominal cramps/Reiter's syndrome.
transmission: by contact after poor personal hygiene/eating contaminated food (not properly cooked)/transferred from faeces of pets/from reptiles/poor kitchen hygiene/raw eggs/unpasteurised milk.
treatment: rehydration/lots of drinking/intravenous fluids/antibiotics.
Marking guidance:
Award [1 max] for each symptom, transmission and treatment.
Award [2 max] if candidate does not mention the type of food poisoning.
"Bacterial food poisoning" is too vague.
Example given must be verifiable.
Distinguish between intracellular and extracellular bacterial infection using Chlamydia and Streptococcus as examples.
Intracellular (Chlamydia)
Extracellular (Streptococcus)
lives inside cells of host
lives outside host cells;
does not produce toxins/no toxins to irritate tissues/does not damage cells
produces toxins/damages cells;
host may not be aware of infection/asymptomatic
produces symptoms (sore throat) so host aware of infection;
not targeted by immune system / (usually) long-term infection
targeted by immune system / (usually) short-term infection;
sexually transmitted disease / infectious conjunctivitis
respiratory infection / pneumonia / skin infections;
Answers do not need to be in table format.