Life Processes PDF 2024-25

Do You Know? n If the alveolar surface were spread out, it would cover about 80 m2. How much do you think the surface area of your body is? Consider how efficient exchange of gases becomes because of the large surface available for the...

Do You Know? n If the alveolar surface were spread out, it would cover about 80 m2. How much do you think the surface area of your body is? Consider how efficient exchange of gases becomes because of the large surface available for the exchange to take place. n If diffusion were to move oxygen in our body, it is estimated that it would take 3 years for a molecule of oxygen to get to our toes from our lungs. Aren’t you glad that we have haemoglobin? Q U E S T I O N S 1. What advantage over an aquatic organism does a terrestrial organism ? have with regard to obtaining oxygen for respiration? 2. What are the different ways in which glucose is oxidised to provide energy in various organisms? 3. How is oxygen and carbon dioxide transported in human beings? 4. How are the lungs designed in human beings to maximise the area for exchange of gases? 5.4 TR ANSPORT ANSPORTAATION 5.4.1 Transportation in Human Beings Activity 5.7 n Visit a health centre in your locality and find out what is the normal range of haemoglobin content in human beings. n Is it the same for children and adults? n Is there any difference in the haemoglobin levels for men and women? n Visit a veterinary clinic in your locality. Find out what is the normal range of haemoglobin content in an animal like the buffalo or cow. n Is this content different in calves, male and female animals? n Compare the difference seen in male and female human beings and animals. n How would the difference, if any, be explained? We have seen in previous sections that blood transports food, oxygen and waste materials in our bodies. In Class IX, we learnt about blood being a fluid connective tissue. Blood consists of a fluid medium called plasma in which the cells are suspended. Plasma transports food, carbon dioxide and nitrogenous wastes in dissolved form. Oxygen is carried by the red blood corpuscles. Many other substances like salts, are also transported by the blood. We thus need a pumping organ to push blood around the body, a network of tubes to reach all the tissues and a system in place to ensure that this network can be repaired if damaged. Life Processes 91 2024-25