Respiration in Plants Test - 5

The TCA cycle starts with the condensation of acetyl group with oxaloacetic acid (OAA) and water to yield citric acid.

Aerobic respiration is the process that leads to a complete oxidation of organic substances in the presence of oxygen, and releases carbon dioxide, water and a large amount of energy present in the substrate. This type of respiration is most common in higher organisms.

Citrate is first isomerised to isocitrate and then followed by decarboxylation, leading to the formation of α-ketoglutaric acid.

Conversion of Succinyl-CoA to Succinate : Succinyl-CoA, like acetyl-CoA, has a strongly negative free energy of hydrolysis of its thioester bond In the next step of the citric acid cycle, energy released in the breakage of this bond is used to drive the synthesis of a phosphoanhydride bond in either GTP or ATP, and succinate is also formed in the process.

The enzyme that catalyzes this reversible reaction is called either succinyl-CoA synthetase or succinic thiokinase;

In kreb cycle glucose has been broken down to release carbon dioxide and eight molecules of NADH₂; two of FADH₂ have been synthesised besides just two molecules of ATP.

Fermentation is the process of anaerobic respiration in which incomplete oxidation leads to formation of ethanol in absence of oxygen. Fermentation occurs in yeast.

During anaerobic respiration only two molecules of ATP is produced by each molecules of glucose.

So, 19 glucose molecules are required to produce 38 ATP molecules.

Cellular respiration takes place in two steps- Glycolysis and Kreb’s cycle. Glycolysis occurs in cytoplasm of cells and Kreb’s cycle in mitochondria. So, first step of respiration takes place in cytoplasm.

Lactic acid is formed by the process of incomplete oxidation of glucose in presence of insufficient oxygen. Lactic acid is formed in muscle cells due to incomplete oxidation to cause cramps.

In mitochondria, protein accumulate in intermembrane space between two layers of mitochondria.