Question

How many ATPs are produced by consumption of 1- glucose molecules in RBC?

Answer 1

RBCs are red blood cells or red blood corpuscles are the most common type of blood cells and are the most abundant in blood. They contain a protein called hemoglobin. Hemoglobin contains a red color compound called heme which gives the red color to the blood.

Complete answer:
RBCs are metabolically active cells which use glucose to make ATP. Life span of RBCs is approximately 120 days. RBCs do not have a nucleus or mitochondria. In RBC, no respiratory chain, no citric cycle and no oxidation of fatty acids or ketone bodies takes place, it is due to absence of mitochondria in RBC. In RBC, anaerobic glycolysis takes place through which energy is obtained in the form of ATP by the glycolytic breakdown glucose followed by the production of lactate. Glycolysis is carried out in 10 steps and they are as follows:
Phosphorylation: glucose is phosphorylated by ATP to form phosphate and is catalyzed by enzyme hexokinase.
Isomerization: rearrangement of structure of carbonyl oxygen from ${C_1}$ to ${C_2}$ takes place. Thus, glucose-6-phosphate gives fructose-6-phosphate.
Phosphorylation: in this step, Fructose-6-phosphate is phosphorylated by ATP to fructose-1,6-bisphosphate and is catalyzed by enzyme phosphofructokinase.
Breakdown: fructose-1,6-bisphosphate is cleaved into glyceraldehyde-3-phosphate (GAP) and dihydroxyacetone phosphate (DAP) and this is catalyzed by enzyme aldolase.
Isomerization: DAP is oxidized to form GAP and this reaction is catalyzed by triose phosphate isomerase enzyme.
Two molecules of glyceraldehyde-3-phosphate are oxidized in this step and 1,3-bisphosphoglycerate is formed.
1,3-bisphosphoglycerate gives 3-phosphoglycerate by substrate level phosphorylation.
Remaining phosphate-ester linkage in 3-phosphoglycerate hydrolyses to form 2-phosphoglycerate (2-PG).
Dehydration of 2-PG: 2-PG is dehydrated by the action of enzyme enolase to PEP.
Transfer of phosphate from PEP to ADP to form pyruvate. This reaction is catalyzed by enzyme pyruvate kinase.
Thus, the reactions involved in glycolysis are:
Glucose is oxidized to pyruvate, NAD+ is reduced to NADH and ADP is phosphorylated to ATP.
Energy yield in glycolysis is 2-ATP.

Note: Glycolysis is also called Embden-Meyerhof-Parnas Pathway or simply EMP pathway. It is known to be a unique pathway which occurs aerobically and anaerobically and does not involve molecular oxygen. It occurs in the cytosol of the cell.