Question

During respiration,
a. 2 PGAL during glycolysis and none of the PGAL produced in Krebs cycle.
b. 2 PGAL during glycolysis and 4 Pyruvic acid are produced in Krebs cycle.
c. 2 PGAL during glycolysis and 2 Pyruvic acid are produced in Krebs cycle.
d. PGAL is not produced during respiratory events.

Answer 1

Hint: Cellular respiration is one of the processes, which helps to obtain the energy from the stored food, It is divided into 3 steps, namely glycolysis, Krebs cycle, and electron transport chain. In this process along with energy molecules like ATP, so. Many by-products are also produced.

Complete answer:
- Cellular respiration is generally an aerobic process, in which cells break down the glucose molecules and produce the energy in the form of ATP.
- The respiration occurs in some steps such as glycolysis, Krebs cycle, and oxidative phosphorylation occurs in the electron transport chain.
- Generally, all these steps occur in the presence of oxygen is called aerobic respiration.
- If this respiration occurs even in the absence of oxygen, then it is called anaerobic respiration, in case of anaerobic respiration, lactic acid is the end product.
- So the first step in glycolysis, in this step, the breaking of glucose takes place, it occurs both in aerobic and anaerobic conditions.
- Each step of glycolysis contains different enzymes, so from all these steps finally, two molecules of pyruvic acid and two net ATP is produced in glycolysis.
- There is a connecting reaction between glycolysis and Krebs cycle, where the pyruvic acid is converted to acetyl CoA
- This acetyl CoA undergoes several reactions, finally, after the two processes, the production 2 ATP, 6 NADH, and 2 FADH and carbon dioxide are produced.
- Finally, in the electron transport chain, most of the ATP is generated, the hydrogen that is removed from the products in previous steps are pumped to mitochondria, where this hydrogen combines with oxygen molecules the water is formed, in this process most of the ATP is produced.
- During the whole respiratory process of glycolysis and Krebs cycle, the formation of 2 phosphoglycerate occurs in the glycolysis only, it won’t take place in the Krebs cycle

Hence, The correct answer is option (A), 2 PGAL during glycolysis and none of the PGAL produced in Krebs cycle.

Note: In the cells, during the respiration, the process of glycolysis takes place in the cytoplasm, whereas the Krebs cycle occurs in the mitochondria, and the electron transport chain takes place in the membrane of mitochondria, wherein the Cristae all the electron transport system is located and all the enzymes are present.