Page 18 - Curriculum Visions Dynamic Book

Carbon in food
Carbohydrate is the name for a wide range
of natural compounds such as sugar and starch, containing carbon, hydrogen and oxygen.
The simplest carbohydrate is glucose.
This in turn is used to make proteins that build plant tissues called cellulose. Soft forms of cellulose make up the fleshy parts of leaves, for example, while a harder, reinforced form
of cellulose called lignin, makes up the veins of leaves, twigs, bark, etc.
Carbohydrates are a store of energy used both by plants and by animals when they eat plants. In this way the energy from the Sun
is converted into energy for all living things.
Because they are so rich in energy, carbohydrates form the main part
of most people’s diets.
Fossilised carbohydrates (fossil plant tissues) are also the source of the
fuels burned as coal and oil.
Oxidation of carbohydrates
The body makes use of
carbohydrates by the
process of oxidation.
It is the reverse of
photosynthesis. Plants store
the carbohydrate glucose as
starch and sucrose. In animals,
glucose is sent around the body
in the bloodstream, and any excess is converted to fat and stored for later use.
EQUATION: Oxidation of glucose
 Concentrated sulphuric acid is added to white sugar.
 It begins to froth and turn brown. This is an exothermic reaction, so a considerable amount of heat is given off in the water, producing steam.
 Typical carbohydrate- containing foods include potatoes, pasta and rice.
Glucose + oxygen ➪ water + carbon dioxide (+ a release of energy) C6H12O6(s) + 6O2(g) ➪ 6H2O(l) + 6CO2(g)(+ energy released)
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