A noncovalent bond between an electronegative atom (commonly oxygen or nitrogen) and a hydrogen atom covalently bonded to another electronegative atom. Particularly important in stabilizing the three-dimensional structure of proteins and formation of base pair s in nucleic acids.
Introduction[edit] The respiratory system serves three principal purposes in the human body: gaseous exchange; sound production; and assistance in compression of the abdomen. It can be divided into two structural divisions, upper and lower, as well as two functional divisions, conducting and respiratory.
Introduction to parts of the respiratory system and their function. Respiratory system consists of the organs that help to breathe. Respiration also known as breathing is the process which delivers oxygen from the external atmosphere to the body and removes the carbon dioxide from body and expels out.The main parts of the respiratory system and their functions are as follows.1  The nostrils.ronchi: The bronchi are the two air tubes that branch off of from the trachea and carry atmospheric air directly into the lungs. Lungs: The main organ of the respiratory system is lungs. Lungs are the site in body where oxygen is taken into and carbon dioxide is expelled out.