Final answer:
A respirometer is used in Exercise 2-6 to measure the oxygen consumption of organisms and requires a CO₂ absorbent for accurate readings. Cellular respiration and adaptations for oxygen transport are vital for understanding metabolic rates in different organisms.
Step-by-step explanation:
The medium used in Exercise 2-6 to determine the oxygen needs of organisms is likely a specialized setup such as a respirometer. A respirometer is designed to measure the oxygen consumption of organisms. As organisms consume oxygen, they produce carbon dioxide. To ensure accurate measurements of just the oxygen consumption, an absorbent for CO₂ would be needed in the experimental setup. Compounds like sodium hydroxide (NaOH) or potassium hydroxide (KOH) are commonly used to absorb CO₂ generated during the respiration process.
Additionally, understanding the oxygen utilization of different organisms is critical to studies relating to cellular respiration and metabolic rate. For instance, aerobically respiring organisms have various adaptations to ensure efficient oxygen transport, like the presence of hemoglobin in red blood cells and specialized respiratory tissues such as gills, lungs, or respiratory passages accompanied by complex circulatory systems.
Furthermore, the physiological oxygen requirement of bacteria can range from strict aerobes, which require oxygen, to strict anaerobes, which are poisoned by oxygen. Facultative anaerobes can grow with or without oxygen, while aerotolerant anaerobes do not require oxygen but are not harmed by it. Microaerophiles require a specific amount of oxygen lower than atmospheric levels. The growth patterns in thioglycolate tube cultures or similar setups help determine these requirements.