Question 1: Gas exchange in the human respiratory system involves the transfer of oxygen into the blood and the removal of carbon dioxide from the blood. This process occurs mainly in the alveoli within the lungs, which provide a large surface area for diffusion.

Answer: Gas exchange involves the diffusion of oxygen into the blood and carbon dioxide out of the blood across the alveolar walls.

Question 1: Define 'alveoli' and explain their role in gas exchange.

Answer: Alveoli are tiny air sacs in the lungs where gas exchange occurs; they provide a large surface area to facilitate diffusion of oxygen and carbon dioxide.

Question 2: Describe how the concentration gradient affects the movement of gases during respiration.

Answer: Gases move from an area of higher concentration to lower concentration across the alveolar membrane, driven by diffusion along the concentration gradient.

Question 1: Calculate the total volume of oxygen (in litres) absorbed by the blood in a person who inhales 0.5 litres of air per breath, with a oxygen concentration of 21%, during 15 breaths. Use the formula: Volume of oxygen = inhaled air volume × oxygen concentration.

Answer: Volume of oxygen = 0.5 L × 0.21 × 15 = 1.575 litres

Question 1: Identify three variables that could affect the rate of gas exchange in an experiment using artificial membranes, and suggest how to control them.

Answer: Variables include temperature, surface area, and gas concentration; control by maintaining constant temperature, using uniform membrane size, and standardising gas concentrations.

Question 2: State two safety precautions to consider when working with respiratory gases in a laboratory setting.

Answer: Ensure proper ventilation and handle gases with appropriate safety equipment to prevent inhalation or leaks.

Question 1: In a study, subjects with higher lung surface areas showed a 20% increase in oxygen absorption compared to those with lower lung surface areas. Explain what this suggests about the relationship between lung surface area and gas exchange efficiency.

Answer: It indicates that a larger lung surface area enhances the efficiency of gas exchange, allowing more oxygen to be absorbed.

Question 1: Explain the process of gas exchange in the alveoli, including how the structure of alveoli facilitates this process and why it is vital for respiration. Your answer should include the role of concentration gradients, the structure of alveoli, and the importance of efficient gas exchange.

Answer: Gas exchange in the alveoli occurs by diffusion, where oxygen moves from the alveolar air into the blood, and carbon dioxide moves from the blood into the alveoli to be exhaled. The alveoli's structure, with a large surface area and thin walls, facilitates rapid diffusion. The concentration gradient, maintained by blood flow and ventilation, ensures gases move efficiently. This process is vital for providing oxygen to body cells and removing waste carbon dioxide, supporting cellular respiration and overall metabolic activity.

Question 1: Describe how understanding gas exchange is important in the development of artificial lungs or ventilators for patients with respiratory diseases.

Answer: Understanding gas exchange allows engineers to design artificial lungs and ventilators that mimic natural processes, ensuring efficient oxygen delivery and carbon dioxide removal for patients with compromised lung function.