In humans, failure to absorb vitamin B₁₂ results in pernicious anaemia - VCE - SSCE Biology - Question 25 - 2005 - Paper 1
Question 25
In humans, failure to absorb vitamin B₁₂ results in pernicious anaemia.
Normally, vitamin B₁₂ enters the stomach and becomes attached to a 'factor' that is produced ... show full transcript
Worked Solution & Example Answer:In humans, failure to absorb vitamin B₁₂ results in pernicious anaemia - VCE - SSCE Biology - Question 25 - 2005 - Paper 1
Step 1
a. oesophagus
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Answer
Vitamin B₁₂ enters the body through the oesophagus, moving towards the stomach.
Step 2
b. cells in stomach lining
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Answer
In the stomach, vitamin B₁₂ attaches to the intrinsic factor produced by the cells in the stomach lining.
Step 3
c. plasma cell in stomach lining
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In patients with pernicious anaemia, plasma cells in the stomach lining produce antibodies against the intrinsic factor.
Step 4
d. small intestine
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Due to the presence of antibodies, the intrinsic factor is rendered unusable, preventing vitamin B₁₂ from being absorbed in the small intestine.
