LIFE SCIENCE

OBJECTIVE LIFE SCIENCE

BIOCHEMISTRY

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
The first step of glycolysis results in the formation of:
A
Glucose-6-Phosphate
B
Fructose-6-Phosphate
C
ATP
D
1, 6 Bis-PhosphoGlycerate
Explanation: 

Detailed explanation-1: -During glycolysis, glucose ultimately breaks down into pyruvate and energy; a total of 2 ATP is derived in the process (Glucose + 2 NAD+ + 2 ADP + 2 Pi–> 2 Pyruvate + 2 NADH + 2 H+ + 2 ATP + 2 H2O). The hydroxyl groups allow for phosphorylation. The specific form of glucose used in glycolysis is glucose 6-phosphate.

Detailed explanation-2: -Step 1: Glucose is phosphorylated by the enzyme hexokinase to form glucose 6-phosphate. Glucose gains energy by being phosphorylated at the expense of one ATP. Step 2: Glucose 6-phosphate is converted into its isomer, fructose 6-phosphate, by an isomerase enzyme.

Detailed explanation-3: -Glucose-6 phosphate is the first intermediate of glucose metabolism and plays a central role in the energy metabolism of the liver. It acts as a hub to metabolically connect glycolysis, the pentose phosphate pathway, glycogen synthesis, de novo lipogenesis, and the hexosamine pathway.

Detailed explanation-4: -Hexokinase converts glucose to glucose 6-phosphate, trapping the glucose molecule inside the cell, thus starting off the process of glycolysis.

Detailed explanation-5: -Stage 2: Isomerization of Glucose-6-Phosphate Glucose-6-phosphate (G6P) is changed into fructose-6-phosphate (F6P) by phosphoglucoisomerase (phosphoglucose isomerase) in the second step. This reaction also requires Mg2+. F6P can enter the glycolytic pathway from the next point.

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