Final answer:
The pool of amino acids used for growth and repair comes from diverse sources in the body, including proteins in the diet and recycled amino acids. These amino acids are then available for the synthesis of proteins, DNA bases, hormones, and other nitrogen-containing compounds. They can also be used as a source of energy in certain situations.
Step-by-step explanation:
The pool of amino acids used for growth and repair comes from various sources in the body. These sources include the amino acids derived from proteins in the diet, amino acids recycled from the body's own proteins, and amino acids synthesized in the liver. Once these amino acids are in the amino acid pool, they can be used for the synthesis of proteins, DNA bases, neurotransmitters, hormones, and other nitrogen-containing compounds. In certain metabolic situations, amino acids can also be used as a source of energy by the body. However, if the amino acids in the pool are not used for biological processes, they are degraded and the nitrogen is excreted in the urine as urea.