Nutrition

Nutrition

Nutrition is the mode of taking food by an organism and its utilisation by the body.

• Nutrition is very important as the nutrients from the food consumed enables living organisms to build their bodies and grow.

• Nutrition helps to repair damaged parts and organs.

• Nutrition also provides energy for carrying out various functions.

Autotrophs and Heterotrophs

Organisms that make food themselves are called autotrophs.

• Plants are an example of autotrophs as they make their own food using carbon dioxide, water and light energy.

• Organisms that rely on others and usually take in ready-made food made by the autotrophs are called  heterotrophs.

• Animals and human beings are an example of heterotrophs as they depend on plants in many ways for their food.

Photosynthesis

Photosynthesis is the process of synthesis of food by green plants.

• This process usually takes place in the leaves of plants.

• The process requires chlorophyll (green coloured pigment), sunlight, carbon dioxide and water. 

Chloroplasts

• The chloroplast is a type of organelle that exists in plants.

• These organelles contain chlorophyll, the green coloured pigment that is responsible for carrying out the process of photosynthesis in plants.

Chlorophyll

• Chlorophyll is the pigment that is responsible for the synthesis of food in green plants.

• This pigment green colour to its bearers and is abundantly found in leaves.

• Chlorophyll is locked inside the chloroplast.

Process of Photosynthesis

The process of photosynthesis takes place in the leaves, the “food factory” of the plants.

• Carbon dioxide is taken in through tiny pores on the leaves called stomata.

• Water and minerals that are required for the process are transported to the leaves from the roots through the stem.

• Chlorophyll helps the leaves use the energy from the sunlight to prepare food using the carbon dioxide, water and minerals.

• Oxygen is released as a by-product  of this process.

Multiple Choice

The tiny pores present in the leaves of the plants for exchange of gases are

called _____

• (a) Stomata

• (b) Tracheae

• (c) Chloroplast

• (d) Spiracles

Multiple Choice

The mode of nutrition in a green plant is ………………

• (a) Heterotrophic

• (b) Saprophytic

• (c) Autotrophic

• (d) Holozoic

Multiple Choice

Which of the following is not required for photosynthesis?

• (a) Sunlight

• (b) Oxygen

• (c) Water

• (d) Carbon dioxid

Multiple Choice

Oxygen liberated during photosynthesis come from ………………

• (a) Water

• (b) Carbon dioxide

• (c) Glucose

• (d) ChlorophyII

Multiple Choice

In the absence of which of the following will photosynthesis not occur in leaves?

• (a) Guard cells

• (b) Chlorophyll

• (c) Vacuole

• (d) Space between cells

Multiple Choice

When we observe the lower surface of a leaf through a magnifying lens we see numerous small openings. Which of the following is the term given to such openings?

• (a) Stomata

• (b) Lamina

• (c) Midrib

• (d) Veins

Multiple Choice

Organisms which prepare food for themselves using simple naturally available raw materials are referred to as

• (a) heterotrophs

• (b) autotrophs

• (c) parasites

• (d) saprophytes

Multiple Choice

Ultimate source of energy for all living organisms is

• Plants

• Atmosphere

• Earth

• Sun

Multiple Choice

Organisms other than plants which contain Chlorophyll are

• Algae

• Protozoa

• Virus

• Fungi

Multiple Choice

The process of Photosynthesis produces

• Carbon Dioxide

• Nitrogen

• Oxygen

• Hydrogen