Question

How many ATP molecules are released when one molecule of glucose is oxidized in our liver cells?
(a)36
(b)38
(c)2
(d)8

Answer 1

Hint: To produce ATP, there is a synthesis of 2 molecules of reduced coenzymes $ { NADH }_{ 2 }$ in glycolysis. And pyruvic acid releases 2 acetyl CoA producing two molecules of reduced coenzyme $ { NADH }_{ 2 }$. The third stage is the Krebs cycle where the synthesis of 3 molecules of reduced coenzyme $ { NADH }_{ 2 }$, 1 molecule of reduced coenzyme $ { FADH }_{ 2 }$, and 1 GTP. The last step is the mitochondrial electron system, which oxidizes the reduced coenzymes ${ NADH }_{ 2 }$ and $ { FADH }_{ 2 }$.

Complete answer:
Glycolysis is the process through which 'high energy' molecules of ATP and NADH are synthesized. The pyruvate molecules then proceed to the link reaction, where acetyl-CoA is produced. During glycolysis, glucose ultimately breaks down into pyruvate and energy; a total of 2 ATP is derived in the process.
$ { C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 }+{ 2 }{ NAD }^{ + }+{ 2 }{ ADP }+{ 2 }{ P }_{ i }\longrightarrow { 2 }{ CH }_{ 3 }{ H }_{ 4 }O_{ 3 }+{ 2 }{ H }_{ 2 }{ O }+{ 2 }{ ATP }+{ 2 }{ NADH }+{ 2 }{ H }^{ + }$
A series of chemical reactions that are used by all aerobic organisms is called the citric acid cycle (CAC) or TCA cycle (tricarboxylic acid cycle) or the Krebs cycle. This metabolic activity releases the stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins. In eukaryotic cells, the citric acid cycle uses two acetyl CoA molecules that are generated from the two pyruvic acid molecules produced in glycolysis.
$ { C }{ _{ 23 }{ H } }{ _{ 38 }{ N }_{ 7 }{ O }_{ 17 }{ P }_{ 3 }{ S } }+{ 6NAD^{ + } }+{ 2 }{ FAD+{ 2 }{ ADP+{ 2 }{ P }_{ i }\longrightarrow { 4 }{ CO }_{ 2 }+{ 6 }{ NADH }+{ 6 }{ H }^{ + }+{ 2 }{ FADH }_{ 2 }+{ 2 }{ ATP } } }$
Across a membrane, there is a transport chain mechanism which is a series of complexes that transfer electrons from electron donors to electron acceptors via redox reactions, and couples this electron transfer with the transfer of protons called electron transport system, which is built up of peptides, enzymes, and other molecules. At last, this mechanism forms 34 molecules of ATP from one molecule of glucose through hydrogen oxidation and also regenerates NAD and FAD for reuse in glycolysis.
So, the correct answer is, ’38’.

Note: In the cells of an organism, a set of metabolic reactions and processes that take place to convert chemical energy from oxygen molecules or nutrients into adenosine triphosphate (ATP), and then release waste products is called cellular respiration. Including the biosynthesis, locomotion or transport of molecules across cell membranes, the chemical energy stored in ATP can then be used to drive processes requiring energy.