Which are the four basic building blocks for catabolic reactions?

Which are the four basic building blocks for catabolic reactions?

• A. Monosaccharides, amino acids, fatty acids, nucleotides
• B. Glucose, glycerol, cholesterol, ATP
• C. Proteins, lipids, carbohydrates, vitamins
• D. Nucleotides, monosaccharides, polysaccharides, amino acids

Answer: (A)

In catabolic metabolism, large biomolecules are broken down into smaller units that can enter energy-producing pathways. The four basic building blocks released from this breakdown are monosaccharides from carbohydrates, amino acids from proteins, fatty acids (and glycerol) from fats, and nucleotides from nucleic acids. Monosaccharides feed into glycolysis and respiration to generate ATP; amino acids are deaminated and funneled into glycolysis or the TCA cycle; fatty acids undergo beta-oxidation to acetyl-CoA and then enter the TCA cycle; nucleotides can be recycled or degraded for use in energy and nucleotide metabolism. These monomer units are the key products of macromolecule breakdown that power the cell’s energy needs.

In catabolic metabolism, large biomolecules are broken down into smaller units that can enter energy-producing pathways. The four basic building blocks released from this breakdown are monosaccharides from carbohydrates, amino acids from proteins, fatty acids (and glycerol) from fats, and nucleotides from nucleic acids. Monosaccharides feed into glycolysis and respiration to generate ATP; amino acids are deaminated and funneled into glycolysis or the TCA cycle; fatty acids undergo beta-oxidation to acetyl-CoA and then enter the TCA cycle; nucleotides can be recycled or degraded for use in energy and nucleotide metabolism. These monomer units are the key products of macromolecule breakdown that power the cell’s energy needs.