SOLUTIONS TO EXERCISES, LESSON 6
The overall function of the human digestive system is to provide materials to be
used by the individual cells of the body. (para 6-1)
The radiant energy of the Sun is stored by plants as the chemical bonds of
glucose molecules. The process for doing this is called photosynthesis.
Ultimately, humans consume either the green plants themselves or the animals
that ate the green plants.
Through the processes of digestion, the glucose is released. It is then delivered
to the cells of the body by the circulatory system.
Within the cells of the body, the energy is released from the glucose molecules
by the process known as metabolic oxidation. The released energy is then used to
produce the compound ATP. Metabolic oxidation and the production of ATP occur
within the mitochondria. The energy for any of the life processes is obtained directly
The three categories of foodstuffs are carbohydrates, lipids, and proteins. Other
The following processes are involved in the human digestive system:
a. Ingestion of foods.
b. Initial processing.
When an individual needs food, he experiences the sensation of hunger. This is
controlled by the hypothalamus area of the brain, which receives information from
various parts of the body for this purpose.
The process of food selection is related both to previous learning and to internal