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IB Biology Digestion Question. - Model
Answer.
a) List three major groups of macromolecules
and the products formed upon complete digestion. (3 marks)
Note: List = don't write too much, Complete
digestion = no intermediate products needed.
Three macromolecules: Carbohydrates, Proteins and
Lipids.
The Products formed for each one:
Carbohydrate --> simple sugars (e.g. glucose finally).
Protein -->
amino acids
Lipids --->
fatty acids + glycerol.
b) Describe where and how the macromolecules listed in a)
are digested. (8 marks)
Note: The key words on this question are Where , How and
Digested.
Also - as the first question asks for
the products of complete digestion there
are probably no marks for the products in part b)
This is a plan. You have to write in whole sentences
the information included in the table.
| Carbohydrates: |
Where |
How Digested |
| |
In the mouth |
mixed with salivary amylase which turns starch into
maltose |
| |
in the duodenum of the small intestine |
pancreatic amylase and maltase break down starch into
maltose them maltose into glucose. |
| Protein: |
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|
| |
in the stomach |
pepsin breaks the proteins into polypeptides |
| |
n the duodenum of the small intestine |
endopeptidase enzyme breaks the polypeptides into amino
acids. |
| Lipids |
|
|
| |
in the stomach |
some digestion of the fats in milk (rennin is involved) |
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in the duodenum of the small intestine |
Bile emulsifies the lipid,
Lipase enzymes break down the lipid into fatty acid and glycerol. |
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