Carbon dioxide respiration

Except as an index of respiration, carbon dioxide is seldom considered in fermentations but plays important roles. Its participation in carbonate equilibria affects pH removal of carbon dioxide by photosynthesis can force the pH above 10 in dense, well-illuminated algal cultures. Several biochemical reactions involve carbon dioxide, so their kinetics and equilibrium concentrations are dependent on gas concentrations, and metabolic rates of associated reactions may also change. Attempts to increase oxygen transfer rates by elevating pressure to get more driving force sometimes encounter poor process performance that might oe attributed to excessive dissolved carbon dioxide. 

The fruits are loaded and the store sealed. Within a few days they consume a proportion of the available oxygen and respire carbon dioxide. Considerable research over the past 60 years, mainlyin the UK [47], has determined the correct balance of gases to prolong the storage life of the different varieties of apples and pears, both home grown and imported. 

In the second stage of respiration, carbon dioxide is produced in a series of reactions. These reactions are called the tricarboxylic acid cycle because some of the molecules formed in the intermediate reactions have three carboxyl groups. 

Carbon dioxide is a colorless, odorless gas with a faint acid taste. Under normal circumstances, the gas is nontoxic, although at high concentrations it interferes with respiration. Carbon dioxide does not support most combustions, which is why CO2 fire extinguish are used in many fire-fighting situations. 

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