1. What is photosynthesis?
All the trees in a forest grow from tiny seeds and, over the years, they grow
bigger and taller. Unlike most animals, plants continue to grow throughout
their lives. The extra material organisms make is called biomass.
People used to think that plants got all the things they needed to grow from
soil. However, if this were true, then all the soil in a forest would soon be used
up and this obviously does not happen! Even very large
trees grow from
tiny seeds. The most
massive organism
on Earth is thought
to be this sequoia
tree (nick-named
‘General Sherman’)
Fruits and vegetable can be grown year after Plants can also be grown without
year in the same soil soil
Today we know that plants need carbon dioxide from air as well
as water from the soil to make their own food. The process that
they use to make their food is called photosynthesis. A green
substance in the leaves, called chlorophyll, absorbs light energy
from the Sun to make photosynthesis happen. Carbon dioxide
and water are the raw materials (reactants) for photosynthesis.
The food made is a sugar. There are many different sorts of
sugar but the one made in photosynthesis is called glucose.
Oxygen is also made in photosynthesis.
Photosynthesis mainly occurs in leaves.
Plants do not
grow properly
if they cannot
get enough
light, like the
plant on the
center of the
photograph