Breathing and Exchange of Gases Test 2

Spirometry is the process of recording the changes in the volume and movement of air in and out of the lungs and the instrument used for this purpose is called a spirometer or respirometer.

The respiratory quotient (RQ) is the ratio of CO₂ produced to O₂ consumed while food is being metabolized.

RQ = CO_{2 eliminated}/O_2 consumed

• The vital capacity (VC) is the maximum volume exhaled after maximum inhalation (IRV + TV + ERV).
• The total lung capacity (TLC), about 6 L, is the maximum amount of air that can fill the lungs (IRV + TV + ERV + RV).

Dead space is the volume of air which is inhaled that does not take part in gas exchange because it remains in the conducting airways or it reaches alveoli that are not perfused or poorly perfused.

• The maximum volume of air that a person can breathe in after forced expiration or the maximum volume of air that a person can breathe out after forced inspiration is called vital capacity. The value of vital capacity varies from 3400 mL to 4800 mL. 
• On the other hand, tidal volume is the air inspired or expired during normal breathing.
• Total lung capacity is the volume of air present in the lungs and respiratory passage after a maximum inspiration.
• Whereas, inspiratory capacity is the total volume of air that a person can inspire after a normal inspiration.

Hence, the correct answer is option B: Vital Capacity

• During inspiration, the diaphragm and external intercostal muscles contract, causing the rib cage to expand and move outward and expanding the thoracic cavity and lung volume.
• During expiration, the diaphragm and intercostals relax, causing the thorax and lungs to recoil.

• Out of the given options, the processes or steps that are included as parts of the respiration in humans include alveolar diffusion of O2​ and CO2​, transport of gases by blood, and diffusion of O2​ and CO2​ between blood and tissues among others.
• However, the utilization of CO2​ by cells for catabolic reactions is not considered a part of respiration in humans.

So, the correct answer is 'The utilisation of CO2​ by cells for catabolic reactions'.

Tidal volume (TV) measures the amount of air that is inspired and expired during a normal breath.

• Tidal volume is approximately 500ml while residual volume is 1100-1200 ml.
• Therefore the residual volume is greater than tidal volume.

The mature mammalian RBC lack the cell organelle mitochondria in it. Since mitochondria are the site of aerobic respiration for cells. Thus, RBCs are unable to perform aerobic respiration and extract their energy by anaerobic means only (by glycolysis).
So, the correct answer to the question is 'Anaerobic'.