Final answer:
Despite the high energy cost of synthesizing glucose from pyruvate through gluconeogenesis, it is worth it because glucose serves as a versatile, transportable and storable form of energy that is crucial for various biosynthetic processes and can also be converted into glycogen for long-term energy storage.
Step-by-step explanation:
The synthesis of glucose from pyruvate during the gluconeogenesis process is highly energy consuming, requiring 4 ATPs and 2 GTPs, totaling 6 ATP equivalents. This endergonic pathway is in fact the reverse of the exergonic process of glycolysis, which breaks down glucose into two pyruvate molecules with a net gain of two ATP molecules.
The energetically expensive nature of gluconeogenesis is justified by the need for glucose as a stable form of stored energy (glycogen) and as a substrate for various biosynthetic processes.
Though glucose synthesis via photosynthesis requires even more energy, 18 ATP and 12 NADPH molecules, the end product serves as essential fuel for cellular activities and growth. Moreover, glucose is a versatile molecule that can be converted into other types of sugars and serves as an energy source that is easier to transport and store compared to ATP, offering a more efficient long-term energy storage solution.