Question

There are 38 molecules of ATP produced in aerobic respiration and how many are formed outside the mitochondria?
(a) 2
(b) 20
(c) 4
(d) 14

Answer 1

Hint: Aerobic respiration is the process of producing energy in the presence of oxygen. The carbohydrates in the presence of oxygen break down into various end products like carbon dioxide, water, and energy.

Complete answer
The beginning of the glycolysis cycle occurs when due to certain conditions provided the glucose molecule is broken down to form two molecules of pyruvic acid. During one cycle one ATP is produced and thus for 1 molecule of glucose 2 glycolysis cycles are required. Therefore, 2 ATP molecules are produced. This cycle occurs outside the mitochondria. The metabolic pathway that includes the oxidation of the glucose molecule partially is known as the Glycolysis cycle. In this cycle, the glucose molecule will break down to form two molecules of pyruvate. In this whole cycle a total of 4 ATP molecules are generated, out of which 2 ATP molecules are utilized in the process itself while the remaining 2 ATP molecules will be the net gain of the glycolysis cycle.

Additional information
-The pyruvate molecule that is formed in the glycolysis by the reduction of glucose is broken into acetyl-CoA which then enters into the Krebs cycle to form citrate when combined with oxaloacetate.
-There are 15 ATP molecules formed by one pyruvate molecule while 30 ATP molecules are formed by two pyruvate molecules.
-Inside the mitochondria, the Krebs cycle occurs. The TCA (Tri Carboxylic Acid) cycle or citric acid cycle will occur inside the inner mitochondrial membrane.
-During the complete process of aerobic respiration the total number of ATP molecules produced are 38. This process occurs through the breakdown of one molecule of glucose. Here the ATP molecules first form in the cytoplasm through glycolysis and then it is moved to the inner mitochondrial membranes where it produces 36 ATP molecules. Thus, the total ATP molecules produced are 38.

So, the correct answer is ‘2’.

Note:
The process of Glycolysis involves catalyzed reactions that involve ten enzymes. Other monosaccharides like fructose and galactose after breakdown will change into their intermediates as in the case of the breakdown of the glucose molecule. The glycolysis has an evolutionary history as it is found in almost all the living organisms as a metabolic pathway and is dependent upon the presence of oxygen.