CLASS X: SCIENCE

CHAPTER 6: LIFE PROCESSES

SESSION: III

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TOPIC TO BE COVERED:

RESPIRATION IN LIVING ORGANISMS

MS. REKHA CHOUDHARY

T.G.T SCIENCE

KENDRIYA VIDYALAYA VIKASPURI

• To help you appreciate life processes in general and respiration in particular
• To help you learn about the different pathways of breakdown of glucose
• To enable you to understand the concept of respiration and its importance for living organisms including humans
• To help you relate the concept of respiration with your daily life

LEARNING OBJECTIVES

• Respiration is a life process in which absorbed food is utilized in the cells of the body to release energy.
• There are two modes of Respiration
• Aerobic Respiration
• Anaerobic Respiration

RESPIRATION

RESPIRATION

Breakdown Of Glucose By Various Pathways

• The energy released during cellular respiration is immediately used to synthesise a molecule called ATP (Adenosine Triphosphate) which is used to fuel all other activities in the cell.
• In these processes, ATP is broken down giving rise to a fixed amount of energy which can drive the endothermic reactions taking place in the cell.

ATP

RESPIRATION IN PLANTS

• Plants exchange gases through stomata, and the large inter-cellular spaces ensure that all cells are in contact with air.
• Carbon dioxide and oxygen are exchanged by diffusion here. They can go into the cells, or away from them and out into the air. The direction of diffusion depends upon the environmental conditions and the requirements of the plant.
• At night, when photosynthesis is restricted, CO2 elimination is the major exchange activity going on.
• During the day, CO2 generated during respiration is used up for photosynthesis, hence there is restricted CO2 release. Instead, oxygen release is the major event at this time.

• Animals have evolved different organs for the uptake of oxygen from the environment and for getting rid of the carbon dioxide produced.
• Terrestrial animals can breathe the oxygen in the atmosphere, but animals that live in water need to use the oxygen dissolved in water.
• Since the amount of dissolved oxygen is fairly low compared to the amount of oxygen in the air, the rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms.
• Fishes take in water through their mouths and force it past the gills where the dissolved oxygen is taken up by blood.

RESPIRATION IN ANIMALS

• Terrestrial organisms use the oxygen in the atmosphere for respiration.
• This oxygen is absorbed by different organs in different animals.
• All these organs have a structure that increases the surface area which is in contact with the oxygen-rich atmosphere.
• Since the exchange of oxygen and carbon dioxide has to take place across this surface, this surface is very fine and delicate.
• In order to protect this surface, it is usually placed within the body, so there have to be passages that will take air to this area.
• In addition, there is a mechanism for moving the air in and out of this area where the oxygen is absorbed.

RESPIRATION IN ANIMALS

Human Respiratory System

• When we breathe in, we lift our ribs and flatten our diaphragm, and the chest cavity becomes larger as a result.
• Because of this, air is sucked into the lungs and fills the expanded alveoli. The blood brings carbon dioxide from the rest of the body for release into the alveoli, and the oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be transported to all the cells in the body.
• During the breathing cycle, When air is taken in and let out, the lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.

BREATHING CYCLE

• When the body size of animals is large, the diffusion pressure alone cannot take care of oxygen delivery to all parts of the body.
• Respiratory pigments take up oxygen from the air in the lungs and carry it to tissues which are deficient in oxygen.
• In Human Beings, the respiratory pigment is Haemoglobin present in Red Blood Cells which has a very high affinity for oxygen.
• Carbon dioxide is more soluble in water than oxygen is and hence is mostly transported in the dissolved form in our blood

Respiration – Exchange Of Gases

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• Respiration is a life process in which absorbed food is utilized in the cells of the body to release energy.
• There are two modes of Respiration - Aerobic and Anaerobic respiration
• During the process of respiration, complex organic compounds such as glucose are broken down to provide energy in the form of ATP. ATP is used to provide energy for other reactions in the cell.
• Carbon dioxide and oxygen are exchanged by diffusion through Stomata in plants.
• Animals have evolved different organs for the uptake of oxygen from the environment and for getting rid of the carbon dioxide produced.

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A QUICK RECAP

• What advantage do terrestrial organisms have over aquatic organisms with regard to obtaining oxygen for respiration?
• How is oxygen and carbon dioxide transported in human beings?
• How are the lungs designed in human beings to maximise the area for exchange of gases?
• How are the alveoli designed to maximise the exchange of gases?
• What would be the consequences of a deficiency of haemoglobin in our bodies?

ASSIGNMENT

THANKYOU�FROM�MS. REKHA CHOUDHARY�T.G.T SCIENCE�KENDRIYA VIDYALAYA VIKASPURI