Respiration in Plants Test - 2

α-Ketoglutarate is produced from decarboxylation of oxalosuccinate by isocitrate dehydrogenase.

Presence of trace quantities of oxygen increases the rate of fermentation. Water molecule is released in Butyric acid fermentation. Ethyl alcohol is a byproduct of lactic acid fermentation by lactic acid bacteria. Yeast cells greatly prefer fermentation to aerobic respiration in presence of abundant oxygen.

Enzymes isomerase and transketolase participate in pentose phosphate pathway. Isomerase produces ribose-5-phosphate and xylulose-5-phosphate from ribulose-5-phosphate. Transketolase acts on sedoheptulose-7-phosphate to produce fructose-6-phosphate and erythrose-4-phosphate. Transketolase also acts upon erythrose-4-phosphate and xylulose-5-phosphate and yields fructose-6-phosphate and glyceraldehyde-3-phosphate.

Conversion of pyruvic acid into acetyl CoA yields energy in the form of NADH, which is equivalent to 3 ATP.

Transketolase activity is decreased by deficiency of thiamine. The co-factor thiamine diphosphate accepts a 2-carbon fragment from a 5-carbon ketose (D-xylulose-5-P), then transfers this fragment to a 5-carbon aldose (D-ribose-5-P) to form a 7-carbon ketose (sedoheptulose-7-P). In another reaction catalysed by transketolase i.e., transfer of a 2-carbon fragment from D-xylulose-5-P to the aldose erythrose-4-phosphate, thiamine acts as a co-factor.

Oxaloacetate provides the carbon skeleton for synthesis of asparagine. Alpha-ketoglutarate forms glutamine, proline, and arginine.

Phosphoglucoisomerase (alternatively known as phosphoglucose isomerase or Glucose-6-phosphate isomerase) are a group of enzymes of the isomerase family (EC 5.3.1.9), so named for their main function in glycolysis and gluconeogenesis.Phosphoglucose isomerase (PGI) produces β-D Fructose 6-phosphate from α-D-Glucose 6-phosphate. The proposed reaction mechanism of PGI for the reversible conversion of glucose-6-phosphate to fructose 6-phosphate involves an acid/base catalysis by the enzyme. The basic mechanism involves the isomerization of an aldose to a ketose.

Ubiquinone is a coenzyme required for the activity of succinate dehydrogenase. Succinate dehydrogenase catalyses the conversion of succinate to fumarate.

One GTP molecule is produced from one acetyl-CoA molecules. Two GTP molecules are produced from two acetyl-CoA molecules.

Glycogen storage disease is a genetic disease which results from deficiency of the enzyme glucose-6-phosphatase. The deficiency impairs the ability of the liver to produce free glucose from glycogen and from gluconeogenesis.