In fact, cysteines are the only amino acids capable of forming covalent bonds, which they do with their particular side chains. Because of side chain interactions, the sequence and location of amino acids in a particular protein guides where the bends and folds occur in that protein (Figure 1).
gas exchange between the pulmonary blood and lungs where oxygen from fresh air in lungs moves into the blood and excess CO2 from the blood moves into the lungs.xygen and carbon dioxide that are transported to and from the lungs and tissue cells where oxygen is pumped throughout the body is CO2 is pumped back into the lungs.
Gas Exchange Between Alveolar Spaces and Capillaries. The function of the respiratory system is to exchange two gases: oxygen and carbon dioxide. The exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. As shown below, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.