<span>Glucose sugar is the simplest organic molecule formed in the leaves of green plants. Glucose, and other forms of carbohydrates, are formed through the process of photosynthesis, which is the process by which plants use the energy from sunlight to combine carbon dioxide and water. These simple glucose molecules are what the plant feeds on to grow and thrive, although glucose may also be converted to starch for energy storage, or to structural carbohydrates such as cellulose or lignin.</span>
Answer:
A. His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane.
Explanation:
Pyruvate is from the breakdown of carbohydrates such as glucose through glycolysis. Glucose enters the cytosol through specific transporters (the GLUT family) and is processed by one of several pathways depending on cellular requirements. Glycolysis occurs in the cytosol and produces a limited amount of ATP, but the end product is two 3-carbon molecules of pyruvate, which maybe diverted again into many pathways depending on the requirements of the cell. In aerobic conditions, pyruvate is primarily transported into the mitochondrial matrix and converted to acetyl-coenzyme A (acetyl-CoA) and carbon dioxide by the pyruvate dehydrogenase complex (PDC).
Initially it was proposed that pyruvate was able to cross the membrane in its undissociated (acid) form but evaluation of its biochemical properties show that it is largely in its ionic form within the cell and should therefore require a transporter.
Transport of pyruvate across the outer mitochondrial membrane appears to be easily accomplished via large non-selective channels such as voltage-dependent anion channels/porin, which enable passive diffusion. Indeed, deficiencies in these channels have been suggested to block pyruvate metabolism
The reason scientists believe this is that there was basically no oxygen in the atmosphere at this time, which meant that cells needed to be anaerobic to survive,<span> going around the problem of no oxygen in the atmosphere.
Hope this helps.</span>
