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Giadiasis is the most common form of non-bacterial diarrhoea of people in Australia - VCE - SSCE Biology - Question 2 - 2002 - Paper 1
Question 2
Giadiasis is the most common form of non-bacterial diarrhoea of people in Australia. The adult parasite, Giardia lamblia, responsible for the disease, is shown in Fi... show full transcript
Worked Solution & Example Answer:Giadiasis is the most common form of non-bacterial diarrhoea of people in Australia - VCE - SSCE Biology - Question 2 - 2002 - Paper 1
Step 1
Suggest an advantage of the cyst stage in the Giardia life cycle to the survival of the species.
Answer
The cyst stage decreases the chance of dehydration after being passed out in the faeces and before transmission to another host. Furthermore, it allows for the parasite to remain dormant for some time, aiding in the transition between hosts, thereby enhancing its chances of survival.
Step 2
Name two features of the adult Giardia and explain how each would assist Giardia’s survival in the upper intestine.
Answer
Feature 1: The sucker located on the ventral side of the Giardia allows it to attach firmly to the intestinal wall, preventing being washed away by the flow of digested food. This attachment provides stability and access to nutrients.
Feature 2: The flagella help the organism to move within the gut of the infected person. This mobility enables Giardia to find optimal locations within the intestine for feeding and reproduction, thereby enhancing its survival.
Step 3