PP 2
CHEMICAL DIGESTION
ABSORPTION
ASSIMILATION
Chemical Digestion
 All large molecules are broken down into




their simplest forms:
Carbohydrates -> sugar
Protein -> Amino Acids
Fats -> Fatty acids / glycerol
For absorption / assimilation as the simplified
molecules are soluble and are easy to absorbe
Enzymes in the alimentary
canal
Where enzyme is
found
What the enzyme Substrate (what
is
it “works on”)
End product
Mouth
& Pancreas
Amylase
Carbohydrate
(starch)
maltose
Small intestine
maltase
maltose
glucose
Stomach
pepsin
protein
Polypeptides
(smaller molecules
of protein)
Small intestine
Protease
(duodenum) (from (trypsin)
pancreas)
Poly peptide
Amino acids
Small intestine
(duodenum(from
pancreas)
fats
Fatty acids +
glycerol
lipase
villi
 Surface area of the villi –
1. Helps speed up rate of absorption
2. Thin walls => only for short distance for
digested food to go before it gets to the
blood or lymph
Capillary absorb:
• sugar / a. a. /
vitamins / inorganic
ions / water
Lacteal absorb:
• fatty acids / glycerol
More on the liver
 Glucose is absorbed into the liver ->
converted to glycogen is not used right away
-> for long term storage into fat.
 Fat can be broken down into glycogen and
then glucose for the body’s use.
 Deamination – removal of the nitrogen
containing parts of the amino acids to form
urea. It is followed by release of energy from
the remainder of the amino acids