Carbon glucose

Cellulose A polymer of six-carbon glucose sugars found in all plant matter the most abundant biological substance on earth. 

The first segment of glucose catabolism is called glycolysis. This process begins when glucose is transported into a cell. In a series of reactions within the cell, each of which requires a specific enzyme, a single six-carbon glucose molecule is converted to... 

The test compound is absent, only alternative nitrogen (ammonia) and carbon (glucose/glycerol/succinate) sources are present. 

The first steps in glycolysis result in the conversion of a six-carbon glucose molecule to two three-carbon intermediates (Figure 6-1). 

The reaction mechanism is similar to the reaction promoted by phosphohexose isomerase in step (2) of glycolysis (Fig. 14-4). After the triose phosphate isomerase reaction, C-1, C-2, and C-3 of the starting glucose are chemically indistinguishable from C-6, C-5, and C-4, respectively (Fig. 14-6), setting up the efficient metabolism of the entire six-carbon glucose molecule. 

Glycolysis, in which, through a series of enzymatic reactions, a six-carbon glucose molecule is converted to two three-carbon pyruvic acid (pyruvate) species with the release of a relatively small amount of the energy in the glucose... 

During glycolysis, the 6-carbon glucose molecule is broken down in a series of steps into two molecules of a 3-carbon compound called pyruvate. There is also a net gain of two molecules of ATP from the reactions of glycolysis. 

J. Skubiszewska-Zieba. R. Leboda, O. Seledets, and V. M. Gun ko, Effect of preparation conditions of carbon-silica adsorbents based on mesoporous silica gel Si-100 and carbonized glucose on their pore structure, Colloids Surf. A 231(1-3), 39-49 (2003). 

Fig. 2.6. The numbers of ATP molecules produced in glycolysis and in the Krebs cycle. Thirty six ATPs result from the splitting of one glucose molecule. Note that each 6-carbon glucose splits into two 3-carbon molecules, each of which generates its own ATPs. Each NADH from the Krebs cycle yields 3 ATPs. Each FADH, yields 2 ATPs. Each NADH from the cytosol yields only 2 ATPs. Each GTP yields one ATP. DHAP, Dihydroxyacetone phosphate. ...

In the first stage of respiration, a six-carbon glucose molecule is split into a pair of three-carbon molecules. Hydrogen Ions and electrons also are produced in glycolysis. These combine with electron carrier ions called nicotinamide adenine dinucleotide (NAD+) to form NADH. NADH is a coenzyme that is made from vitamin B4, which is also called niacin or nicotinic acid. ATP and NADH serve as temporary storage sites for energy and electrons, respectively, during respiration. Two molecules of ATP are used, and four molecules are produced. ... 

Two pyruvate molecules. At the end of glycolysis the six-carbon glucose molecule has been converted into two three-carbon pyruvate molecules. The fate of the p)rruvate also depends on whether the reactions are occurring in the presence or absence of oxygen. Under aerobic conditions it is used to produce acetyl CoA destined for the citric acid cycle and complete oxidation. Under anaerobic conditions it is used as an electron acceptor in fermentation reactions. 

Common sugars typically have not one, but multiple chiral carbons. Glucose, for example, contains four... 

Fatty acids are synthesized mainly in the liver in humans, with dietary glucose serving as the major source of carbon. Glucose is converted through glycolysis to pyruvate, which enters the mitochondrion and forms both acetyl CoA and oxaloacetate (Fig. 33.1). These two compounds condense, forming citrate. Citrate is transported to the cytosol, where it is cleaved to form acetyl CoA, the source of carbon for the reactions that occur on the fatty acid synthase complex. The key regulatory enzyme for the process, acetyl CoA carboxylase, produces malonyl CoA from acetyl CoA. 

Conversion of Six-Carbon Glucose to Three-Carbon Glyceraldehyde-3-Phosphate... 

Carbon glucose is cleaved to, yield 3-carbon pyruvate ATP is produced... 

It is instructive to compare the energy yield from the complete oxidation of fatty acids with that obtained from an equivalent amount of glncose becanse both are important constituents of the diet. In Section 13.8, we saw that the oxidation of a single glucose molecule produces 32 ATP molecules. The complete oxidation of three 6-carbon glucose molecules... 

The double-isotope dansyl microassay has also been used to measure release of amino acids from brain preparations in vitro (Snodgrass and Iversen, 1973). Rat cortical tissue was chopped using a Mcllwam chopper and suspended in Krebs-bi-carbonate-glucose medium. Electrical stimulation was applied and, following superfusion, the medium was changed for a Krebs-bicarbonate buffer containing 55 mM KCl. In this way,... 

The word carbohydrate arose because molecular formulas of these compounds can be expressed as hydrates of carbon. Glucose, for example, has the molecular formula CgHijOg, which might be written as Cg(H20)6. Although this type of formula is useless in studying the chemistry of carbohydrates, the old name persists. 

Overall, the pathway of glycolysis is cleavage of the six-carbon glucose molecule into two three-carbon units. The key steps in the pathway are ... 

FIGURE 18.9 In glycolysis, the six-carbon glucose molecule is degraded to yield two three-carbon pymvate molecules. A net of two ATP is produced along with two NADH. Where in the glycolysis pathway is glucose cleaved to yield two three-carbon... 

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