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Date May 2017 Marks available 3 Reference code 17M.3.SL.TZ1.18
Level Standard level Paper Paper 3 Time zone Time zone 1
Command term Deduce Question number 18 Adapted from N/A

Question

State two roles of hydrochloric acid in gastric juice.

Role 1:

Role 2:

[2]
a.

Pancreatic juice is secreted into the pancreatic duct which carries these secretions to the small intestine.

The hormone secretin is released by the small intestine when hydrochloric acid enters it from the stomach. The data below show the volume of pancreatic juice released after an injection of secretin.

Pancreatic secretions contain sodium hydrogen carbonate, making them basic.

Deduce the significance of the response by the pancreas to secretin.

[3]
b.

State one cause of stomach ulcers.

[1]
c.

Markscheme

a. activation of enzymes/protease/pepsinogen 

b. bactericidal action / kills pathogens 

c. hydrolysis / breakdown of food

a.

a. secretin stimulates an increase in pancreatic secretions 

b. pancreatic secretions are released rapidly / within 10 minutes 

c. «NaHCO3 in pancreatic secretions» neutralises stomach acid / HCI 

d. provides optimal conditions for digestion / enzymes «in the small intestine» 

e. by 40 minutes no more hydrochloric acid enters the small intestine

b.

an infection by Helicobacter pylori / H. pylori
OR
overuse of NSAIDs /aspirin / ibuprofen

c.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.

Syllabus sections

Option D: Human physiology » Option D: Human physiology (Core topics) » D.2 Digestion
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Option D: Human physiology » Option D: Human physiology (Core topics)
Option D: Human physiology

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