NCERT Book Class 7 Science Chapter 1 Nutrition in Plants

1 Nutrition in Plants

I
n Class VI you learnt that food is utilisation by the body. The mode of
essential for all living organisms. nutrition in which organisms make food
You also learnt that carbohydrates, themselves from simple substances is
proteins, fats, vitamins and minerals are called autotrophic (auto = self; trophos
components of food. These components = nourishment) nutrition. Therefore,
of food are called nutrients and are plants are called autotrophs. Animals
necessary for our body. and most other organisms take in food
All living organisms require food. prepared by plants. They are called
Plants can synthesise food for heterotrophs (heteros = other).
themselves but animals including
humans cannot. They get it from plants
or animals that eat plants. Thus,
humans and animals are directly or Paheli wants to know why
indirectly dependent on plants. our body cannot make food
from carbon dioxide, water
and minerals like plants do.
Boojho wants to know
how plants prepare Now we may ask where the food
their own food. factories of plants are located: whether
food is made in all parts of a plant or
only in certain parts? How do plants
1.1 MODE OF NUTRITION IN PLANTS
obtain the raw materials from the
Plants are the only organisms that can surroundings? How do they transport
prepare food for themselves by using them to the food factories of plants?
water, carbon dioxide and minerals. The
raw materials are present in their 1.2 PHOTOSYNTHESIS — FOOD
surroundings. MAKING PROCESS IN PLANTS
The nutrients enable living Leaves are the food factories of plants.
organisms to build their bodies, to grow, Therefore, all the raw materials must
to repair damaged parts of their bodies reach the leaf. Water and minerals
and provide the energy to carry out life present in the soil are absorbed by the
processes. Nutrition is the mode of roots and transported to the leaves.
taking food by an organism and its Carbon dioxide from air is taken in