NCERT Solutions Class 11 Biology Chapter 17 Breathing and Exchange Of Gases. NCERT book for Biology in Class 11 is strongly suggested by teachers and the CBSE and NCERT boards. These books are now mandatory in various schools. The questions in exams will strictly come from the topics given in these books. Please download the NCERT solutions for Class 11 Biology free in PDF made by teachers of the best schools in India. These solutions are carefully compiled to give detailed understanding of the concepts and also steps of solutions. The NCERT solutions are free to download in pdf format. Please refer to the download link below to download the pdf file and also refer to other chapters and subjects to get the solutions to Biology NCERT book questions and exercises.
1. Define vital capacity. What is its significance?
Answer The maximum volume of air a person can breathe in after a forced expiration is called vital capacity. It helps in finding differentiate causes of lung disease.
2. State the volume of air remaining in the lungs after a normal breathing.
Answer The volume of air remaining in the lungs after a normal breathing is called Functional residual capacity (FRC). This includes expiratory reserve volume (ERV) and residual volume (RV). ERV=1000 to 1100 ml RV = 1100 to 1200 ml Thus, FRC = 2100 to 2300 ml
3. Diffusion of gases occurs in the alveolar region only and not in the other parts of respiratory system. Why?
Answer Alveoli are the primary sites of exchange of gases. Exchange of gases also occur between blood and tissues. O2 and CO2 are exchanged in these sites by simple diffusion mainly based on pressure/concentration gradient. Alveolar region is having enough pressure gradient to facilitate diffusion of gases while other regions of the respiratory system don’t have the required pressure gradient. Solubility of the gases as well as the thickness of the membranes involved in diffusion are also some important factors that can affect the rate of diffusion.
4. What are the major transport mechanisms for CO2? Explain.
Answer CO2 is carried by haemoglobin as carbamino-haemoglobin (about 20-25 per cent). This binding is related to the partial pressure of CO2 . pO2 is a major factor which could affect this binding. When pCO2 is high and pO2 is low as in the tissues, more binding of carbon dioxide occurs whereas, when the pCO2 is low and pO2 is high as in the alveoli, dissociation of CO2 from carbamino-haemoglobin takes place, i.e.
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