Question

An E. coli cell can import glucose molecules by group translocation or simple transport. If the cell is only using group translocation and is under anaerobic conditions, how many total ATP will be produced for 3 glucose molecules?

Answer 1

Ans) 6 ATP molecules

Group translocation is characterized by modification of the transported species across the membrane i.e. transported substances are chemically modified during the transport process. A classic example of group translocation is phosphotransferase system. It is first discovered in 1964 by the Saul Roseman. The phosphotransferase system involved in the transport of sugars such as glucose, fructose, and mannose. The sugars are modified by the addition of phosphate groups in phosphotransferase system. The enzyme 1 and HPR are the two proteins which are involved in the group translocation.

In the cytoplasm of a cell, the glucose is degraded by the glycolysis pathway. One glucose molecule (6 Carbon compound) enters into glycolysis produces two molecules of pyruvate (3 Carbon compound). During the degradation of glucose molecule produces two molecules of NADH and four ATPs but two ATPs are utilized for glycolysis process so the net gain is two ATPs at the end of glycolysis. Finally, only two ATP molecules are produced from degradation of one molecule of glucose by glycolysis pathway. By the degradation of three glucose molecules produces net 6 ATP molecules (12 ATPs are produced but 6 are used during glycolysis so net ATPs are 6 only).