A: The corneal reflex is an involuntary closing of the eyelids when the cornea is touched by a foreign object. The function of this reflex is to protect the eye from damage. Absence of a corneal reflex may indicate damage to the fifth and seventh cranial nerves, which mediate the reflex.
Cellular respiration is the process by which the chemical energy of food molecules is released and partially captured in the form of ATP. Carbohydrates, fats, and proteins can all be used as fuels in cellular respiration, but glucose is most commonly used as an example to examine the reactions and pathways involved.
The reactions involved in respiration are catabolic reactions, which break large molecules into smaller ones, releasing energy in the process, as weak so-called high-energy bonds are replaced by stronger bonds in the products. Respiration is one of the key ways a cell gains useful energy to fuel cellular activity. Cellular respiration is considered an exothermic redox reaction which releases heat. The overall reaction occurs in a series of biochemical steps, most of which are redox reactions themselves. Although technically, cellular respiration is a combustion reaction, it clearly does not resemble one when it occurs in a living cell due to slow release of energy from the series of reactions.