Final answer:
In summary, the central metabolic pathways involve the conversion of glucose to pyruvate through glycolysis, followed by the transformation of pyruvate to acetyl-CoA for entry into the TCA cycle. The correct statements about these pathways are that glycolysis produces pyruvate (a), carbon enters the TCA cycle as acetyl-CoA (c), and the TCA cycle yields ATP, precursor metabolites, and reducing power (e).
Step-by-step explanation:
The central metabolic pathways include glycolysis, the Tricarboxylic Acid (TCA) cycle, also known as the Krebs cycle or citric acid cycle, and the pentose phosphate pathway. Answering the question regarding the correct statements:
- a. Glycolysis converts one 6-C molecule of glucose to two 3-C molecules of pyruvate. This is correct, as the process of glycolysis breaks down glucose into two molecules of pyruvate, resulting in a net gain of ATP and the reduction of NAD+ to NADH.
- b. Carbon from glycolysis enters the TCA cycle in the form of pyruvate. This is incorrect as carbon enters the TCA cycle as acetyl-CoA, not pyruvate.
- c. Carbon from glycolysis enters the TCA cycle in the form of acetyl-CoA. This is correct, as pyruvate is converted to acetyl-CoA before entering the TCA cycle, where it joins with oxaloacetate to form citrate.
- d. The pentose phosphate pathway yields ATP, precursor metabolites and reducing power. This is partly incorrect; although the pathway generates precursor metabolites and reducing power in the form of NADPH, it does not produce ATP.
- e. The TCA cycle yields ATP, precursor metabolites, and reducing power. This is correct, as the TCA cycle generates ATP (or GTP, depending on the organism), as well as NADH and FADH2 which are reducing agents and various precursor metabolites.