Breath. Glikoliz

you are: Breath

Distinguish three stages of process of breath. The first of them - sequence of the reactions proceeding in anaerobnyh conditions, - carries the name glikoliza or ways of Embdena - Meyer-gofa - Parnassus (EMP). This stage occurs in cytoplasm where geksozy are split and partially are oxidised with formation pirovinogradnoj acids (the three-carbon organic acid usually considered in the ionised form, i.e. In shape piruvationa). As geksozy - rather stable connections, metabolic energy should be spent for activation of initial reactions glikoliza.

Two molecules ATR are spent for transformation geksozy in geksozodifosfat; then fosforilirovannaja geksoza it is split with formation of two triozofosfatov which in a series of intermediate reactions are oxidised to piruvata. In these last reactions four molecules ATR so the total result glikoliza is reduced to synthesis of two molecules ATR are formed. Besides direct formation ATR in process glikoliza, ATR it is formed also thanks to that the part liberated at glikolize energy is spent for restoration kofaktora nikotinamidadenindinukleotida which thus passes from the oxidised form (NAD +) in restored (NADH). Later this energy (in the form of NADH) is used for synthesis ATR at oxidising fosforilirovanii in a carrying over chain elektronov.

In the presence of oxygen formed during time glikoliza piruvat it is used in the second stage of breath in which it is oxidised to СО2 and Н2O with formation of new molecules ATR. For lack of oxygen piruvat enters the reactions which sequence carries the fermentation name (fig. 5.5); at fermentation of essential additional synthesis ATR does not occur. On bad drenirovannyh soils an oxygen lack - a usual problem; when the soil is boggy, oxygen level in it below an optimum. thus in root cages aerobic breath is limited and synthesis ATR is accordingly limited. And as absorption of mineral substances from soil is connected with expenditure ATR, at the plants growing on bad drenirovannyh soils, symptoms of sharp insufficiency of those or other mineral elements are often found out (see gl. 7).