Question

Why is glucose preferred over pyruvate as an energy source in cellular metabolism?

a. Glucose diffuses more easily across lipid bilayers
b. Pyruvate transporters are scarce in most cells
c. Glycolysis intermediates are essential for metabolic branching
d. Pyruvate lacks energy-yielding potential

Which transporters facilitate the entry of pyruvate into cells?
a. Glucose transporters
b. Monocarboxylate transporters
c. ATP transporters
d. Pyruvate receptors

Why is glycolysis considered an important metabolic junction in cellular metabolism?
a. It breaks down pyruvate efficiently
b. It connects with various metabolic pathways
c. It produces a large amount of ATP
d. It exclusively uses glucose as a substrate

How does the loss of 2 ATP and 2 NADH during glycolysis affect cellular energy balance?
a. Negligible impact on ATP production
b. Significant increase in ATP production
c. Results in energy surplus
d. Results in energy deficit

Why is glucose preferred over pyruvate in terms of availability and production?
a. Glucose is easier to transport
b. Pyruvate is abundantly present in cells
c. Glucose is easy to manufacture or isolate
d. Pyruvate has higher energy content

Answer 1

Glucose is the preferred energy source because it is more readily available and acts as a crucial intermediate in various metabolic pathways. It is transported into cells by GLUT proteins, while pyruvate uses monocarboxylate transporters. The initial use of ATP in glycolysis facilitates a larger energy yield, making glucose efficient for cellular metabolism.

Step-by-step explanation:

Glucose is preferred over pyruvate as an energy source in cellular metabolism because glycolysis intermediates are essential for metabolic branching, meaning glycolysis is an important metabolic junction that connects with various metabolic pathways. This process does not use oxygen and takes place in the cytoplasm of cells, where glucose is facilitated by GLUT proteins for diffusion into cells. Pyruvate, on the other hand, enters the cell via monocarboxylate transporters. The consumption of 2 ATP during glycolysis to eventually yield a net gain illustrates an initial investment for a larger return of energy. Considering availability and production, glucose is more readily accessible as it is transported across the wall of the small intestine into the bloodstream post-digestion and can be stored as glycogen in the liver for later use. In contrast, pyruvate is a product of glycolysis and not as readily available as a direct energy source.