The branch of the U.S. government that is composed of the president and all the individuals, agencies, and departments that report to the president, and that is responsible for administering and enforcing the laws that Congress passes.
Proteins are biological polymers composed of amino acids. Amino acids, linked together by peptide bonds, form a polypeptide chain. One or more polypeptide chains twisted into a 3-D shape form a protein. Proteins have complex shapes that include various folds, loops, and curves.
A peptide bond (amide bond) is a covalent chemical bond formed between two amino acid molecules. peptide bond can be broken by hydrolysis (the adding of water). In the presence of water they will break down and release 8â16 kilojoule / mol (2â4 kcal / mol) of free energy. This process is extremely slow. In living organisms, the process is catalyzed by enzymes.