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What happens if we don’t have enough
enzymes?
Digestion would be too slow for
efficient nutrient absorption.
What is the role of hydrochloric acid in the stomach?
It kills bacteria and provides the acidic pH needed for pepsin to digest proteins.
How do pepsin and trypsin work differently?
Pepsin works in the stomach and needs an acidic environment to break down proteins.
Trypsin works in the small intestine and needs an alkaline environment.
Why does trypsin not work in the stomach?
Trypsin only works in an alkaline environment, but the stomach is acidic. That’s why it is
active in the small intestine, not the stomach.
What would happen if bile was missing?
The acidic food from the stomach would not be neutralized, and enzymes like trypsin would
not work properly in the small intestine
Why does the stomach need a low pH?
The stomach needs a low pH (acidic environment) to activate pepsin, the enzyme that digests
proteins. It also helps kill harmful microorganisms in food.
What would happen if the stomach did not produce hydrochloric acid?
Pepsin would not be activated, so proteins wouldn’t be digested properly. Bacteria in food
might also survive, leading to infections.
What happens if food from the stomach stays acidic in the small intestine?
Enzymes in the small intestine (like trypsin) wouldn’t work properly because they need an
alkaline environment. This would slow down digestion
Why does the small intestine need a different pH from the stomach?
The stomach is acidic for pepsin, but the small intestine needs an alkaline pH for trypsin and
other enzymes to work properly.
Where does the body absorb most of its nutrients?
small intestine
Where is most water absorbed?
small intestine
How does bile help digestion in the small intestine?
Bile is alkaline, so it neutralizes the acidic mixture of food from the stomach. This provides the
right pH for enzymes like trypsin to work in the small intestine.
Imagine you ate a big meal, and your stomach
has been working hard to break it down with
acid. Now, this acidic food enters the small
intestine, where enzymes need an alkaline
environment to work. What do you think
happens next?
bile is
an alkaline mixture
that neutralises the
acidic mixture of
food and gastric
juices entering the
duodeum from the
stomach, to provide
a suitable pH for
enzyme action
What does bile do to pH levels in the small intestine?
Bile raises the pH, making the small intestine alkaline so that trypsin and other enzymes can
function properly
Why do different enzymes work in different
parts of the digestive system?
Enzymes function
best at specific pH levels, e.g., pepsin in acidic
stomach conditions.
Why do you think the body separates
water-soluble and fat-soluble nutrient absorption?
The body separates them because water-soluble
nutrients can mix with blood easily, while fats need a different transport system (the lymphatic system)
since they do not dissolve in water)