Page 130 - General and Inorganic Chemistry for Advanced Secondary Schools Students Book Form Five and Six

Biology for Secondary Schools

a by-product of respiration, carbon Production of food
dioxide is harmful if excessive amounts Photosynthesis produces food for the
accumulate in the atmosphere. The plants. Some animals, such as cattle,
accumulated carbon dioxide forms a goats, and zebra depend directly on
layer, which traps heat escaping from plants as their source of food. Such
FOR ONLINE READING ONLY
the earth’s surface and re-radiates it animals are called herbivores. Other
back to the earth’s surface, thus causing animals called carnivores, such as lions,
global warming. hyenas, and leopards feed directly on
herbivores by killing and eating them.
Animals, such as human beings and
Conversion of solar energy into monkeys depend on both plants and
chemical energy animals as their source of food. These
Photosynthesis converts sunlight are called omnivores.
energy into chemical energy. The sun is
the primary source of all forms of energy The extra food produced by plants

used in life processes. This energy is is stored in various plant organs.
used by plants as well as animals. It is The stored food is used by the plants
made available to living things through during adverse conditions, such
photosynthesis. Animals obtain energy as drought when the plant cannot
by feeding on plants or animals that synthesise adequate amounts of food.
eat plants. Thus, sunlight energy is The underground storage organs of the
converted into chemical energy that plants are formed from modified stems,
leaves or roots. There are several types
is stored in organic food molecules. of underground storage organs, such
The energy stored in organic food as bulbs, tubers, roots, corms, and

molecules is then released into the cells rhizomes.
during respiration. This energy is used
in life processes, such as movement, Bulb: This is an underground storage
reproduction, sensitivity, growth, and organ formed from the modification
excretion. of the plant stem and leaves. An onion
is an example of a bulb, as shown in
Figure 6.9.

124 Student’s Book Form One Student’s Book Form One

15/10/2024 09:24:39
Biology FORM 1 new.indd 124
Biology FORM 1 new.indd 124 15/10/2024 09:24:39