6.1.1 Explain why digestion of large food molecules
is essential.
6.1.2 Explain the need for enzymes in
digestion
6.1.3 State the source, substrate, products and
optimum pH conditions for one amylase, one protease and
one lipase
6.1.4 Draw and label a diagram of the digestive
system.
6.1.5 Outline the function of the stomach, small
intestine and large intestine.
6.1.6 Distinguish between absorption and
assimilation.
6.1.7 Explain how the structure of the villus is
related to its role in absorption and transport of the
products of digestion.
H.2.1 State that digestive juices are secreted into
the alimentary canal by glands, including salivary
glands, gastric glands in the stomach wall, the pancreas
and the wall of the small intestine.
H.2.2 Explain the structural features of
exocrine gland cells.
H.2.3 Compare the composition of saliva, gastric
juice and pancreatic juice.
H.2.4 Outline the control of digestive juice
secretion by nerves and hormones, using the example of
secretion of gastric juice.
H.2.5 Outline the role of membrane-bound enzymes on
the surface of epithelial cells in the small intestine
in digestion.
H.2.6 Outline the reasons for cellulose not being
digested in the alimentary canal.
H.2.7 Explain why pepsin and trypsin are initially
synthesized as inactive precursors and how they are
subsequently activated.
H.2.8 Discuss the roles of gastric acid and
Helicobacter pylori in the development of stomach
ulcers and stomach cancers.
H.2.9 Explain the problem of lipid digestion in a
hydrophilic medium and the role of bile in overcoming
this.
H.3.1 Draw and label a diagram showing a transverse
section of the ileum as seen under a light microscope.
H.3.2 Explain the structural features of an
epithelial cell of a villus as seen in electron
micrographs, including microvilli, mitochondria,
pinocytotic vesicles and tight junctions.
H.3.3 Explain the mechanisms used by the ileum to
absorb and transport food, including facilitated
diffusion, active transport and endocytosis.
H.3.4 List the materials that are not absorbed and
are egested.
