Nutrition In Plants

Science Class Seven

What is Nutrition

The mode of taking food by an organism and its utilization by the body is called Nutrition.

Nutrients

The components of food are called nutrients. Vitamins, minerals, proteins, fats and carbohydrates are the main components of food and are called nutrients.

All living organism require food. Food gives nutrition.

Nutrition is necessary to grow, to repair damaged tissues, to be healthy and ultimately to survive. Nutrition provides energy to carry out life processes. Nutrition is essential for living organism.

Only plants can make their food

Plants can make their food themselves but animals cannot. Animals get food from plants or animals that eat plants.

Example:

Deer, elephant, cow, buffaloes, etc. eat plants. While tiger, lion, etc. eat deer, rabbit, etc. which eat plants.

Thus, human and animals are directly or indirectly dependent on plants.

Mode of Nutrition in Plants

On the basis of getting nutrition, organisms can be divided into two types, these are Autotrophic Nutrition and Heterotrophic Nutrition.

(1) Autotrophic Nutrition

The mode of nutrition in which organisms make food themselves from simple substances present in their surrounding, such as water, carbon dioxide and minerals is called Autotrophic Mode of Nutrition or Autotrophic Nutrition. For example green plants make their food themselves.

Organisms which feed on autotrophic nutrition are called Autotrophs.

(2) Heterotrophic Nutrition

The mode of nutrition in which organisms depends on other organism for their food is called Heterotrophic Mode of Nutrition or Heterotrophic Nutrition.

Example: Man including other animals takes in readymade food prepared by plants. Either they eat plant or animals which eat plants.

Organisms which feed on heterotrophic mode of nutrition are called Heterotrophs.

Types of organisms on the basis of mode of Nutrition

On the basis of mode of nutrition, organisms also can be divided into two types, these are Autotrophs and Heterotrophs.

Autotrophs

Organisms who make their food themselves are called Autotrophs.

In other words, autotrophs means those organisms which make their food themselves.

Since plants make their food themselves, thus plants are called Autorophs

Not all plants, rather only green plants make their food themselves. As green plants produce food so, green plants are also known as producer (autotroph). Green plant (autotroph) converts the physical energy from sunlight into chemical energy in the form of carbon. This process of making of their food by green plants is called PHOTOSYNTHESIS.

Heterotrophs

Organisms which do not make their food themselves and are dependent on food produced by autrotrophs; are called Heterotrophs. This mode of nutrition is called heterotrophic mode of nutrition. So, Animals and most of the other organisms take readymade food prepared by the plants are called Heterotrophs.

Animals including human beings are Heterotrophs.

Photosynthesis: The process of food making by plants

The food making process by green plants after taking water, carbon dioxide and other minerals from environment is called PHOTOSYNTHESIS.

Photosynthesis is a Greek word in which 'Photo' stands for 'light' and 'synthesis' stands for 'putting together' or 'to prepare'.

class 7th science Nutrition in plants photosynthesis

In the process of photosynthesis carbon dioxide is converted into organic compounds, especially sugars, in the presence of sunlight. Energy is absorbed from the sunlight in this process.

Photosynthesis is a unique process on earth.

Photosynthesis occurs in plants, algae, and many species of bacteria. The organisms that make their food by the process of photosynthesis are called 'Photoautotrophs', since they can create their own food using sunlight.

Essential components for the process of Photosynthesis

For the process of photosynthesis presence of chlorophyll, sunlight, carbon dioxide and water are necessary. In the absence of anyone of these, photosynthesis would not be taken place.

Leaves of the plants contain chlorophyll. Leaves of the plants are of green colours because of the presence of chlorophyll.

Process of photosynthesis happens in the leaves of green plants. This is the cause that leaves are called the kitchen of the plants.

Xylem

Water and other minerals are absorbed from the soil by the root of the plants. There are small hair like pipes runs through the stems of the plant, which transports the water and minerals from soil to the other parts of plant. These water conducting tissues are called xylem. Water and minerals are transported to the leaves of the plant through the xylem.

Stomata

Leaves have tiny pores on the lower surface, called STOMATA. Through stomata leaves absorb carbon dioxide from the air.]

class 7th science Nutrition in plants stomata

Green colored of chloroplast, which is due to the presence of chlorophyll present in the leaves, is trapped energy from sunlight. Chlorophyll is a green colour pigment. The upper surface of leaves has chloroplast, so that more quantity of sunlight can be absorbed.

In the presence of sunlight and chlorophyll, carbon dioxide and water are converted into glucose and oxygen is released.

Reaction during photoshynthesis:

Carbon dioxide + Water + sunlight + chlorophyll ⇒ Glucose + Oxygen

The prepared Glucose is converted into insoluble form as starch. This starch is transported to the other part of the plants by the stem.

Phloem is the tissue present in the stem of plants. Phloem transports synthesized food to the other parts of plant. The synthesized food is stored in the leaves, stems, roots and fruits of the plants.

Oxygen, which is prepared in this process, is emitted out in the air through stomata of the leaves.

Significance of the photosynthesis

(a) Photosynthesis is the primary source of food for all living organism. All animals are depended directly or indirectly on the plants.

(b) Carbon dioxide which we and other animals release during the process of respiration is a dangerous gas. Carbon dioxide is absorbed by the plants in the process of photosynthesis.

(c) Oxygen is released in the process of photosynthesis which is necessary for the plants and animals to live.

(d) In photosynthesis the process of absorption of carbon dioxide and release of oxygen maintains the level of both of the gases in the atmosphere.

What does happen, if there were no photosynthesis on the earth?

It is the photosynthesis by which plants make food. Animals including human depends on food prepared by plants. We eat food comes from plants or we eat animals which eat plants. Thus all animals depend directly or indirectly on food prepared by plants by the process of photosynthesis.

Thus in the absence of photosynthesis there were no food on the earth. And in the absence of food, life does not exist on earth.

So, if there were no photosynthesis on the earth, life may be not possible. And we may not live on the earth to study this photosynthesis here. In the absence of photosynthesis earth may be nothing but only a barren land, like other planets in the universe. We may not be alive to see the several amazing phenomenon of our beautiful earth.

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