Chapter 13 (Gaseous Exchange) F.Sc 1st Year Biology Short Questions

Differentiate between respiration and photorespiration.

Respiration is a chemical reaction where Oxygen is used to breakdown Glucose in order to generate energy which is then used by the cell to function. Respiratory activity which occurs in plants during daytime is called photorespiration. Rubisco fixes oxygen instead of carbon dioxide during photorespiration.

How expiration occur in man?

During expiration the muscles of ribs become relaxed, the ribs move downward and inward. In this way from the side of chest cavity the space becomes less. At the same time the muscles of the diaphragm becomes more domelike, the space in the chest cavity is also reduced from the floor as well. This reduction in space of the chest cavity exerts pressure on the lungs and the inside air moves out.[the_ad id=”17142″]

Write down three factors which affect the capacity of haemoglobin to combine with oxygen.

concentration of CO2 pH and temperature.

Name respiratory pigment of muscle. Give its role.

Myoglobin is iron containing protein pigment occurring in muscle fibres, it serves as an intermediate compound for the transfer of oxygen from haemogobin to aerobic metabolic processes of the muscle cells. Myoglobin can also store some oxygen.

Define residual volume of lung. What is residual volume of human?

The residual volume is the difference between the functional residual capacity, which is the amount of air left in the lungs after a natural exhalation, and the expiratory reserve volume, which is the maximum amount of air a person can still let out after natural exhalation. Residual volume of human is 1.5 litre.

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