Fill-in the blanks.Proteins have evolved to function optimally in specific cellular or extracellular environments. Exposure to conditions that are different from these environments can induce structural changes, both large and small. A loss of 3D-structure sufficient to cause loss of function is called denaturation. The denatured state does not necessarily mean that the protein is complete unfolded. Under most conditions, denatured proteins exist in a set of partially folded states.The following reagents or conditions denature proteins: (a) high temperature(b) detergents (c) low or high pH (d) denaturants (urea, guanidinium chloride)Urea guanidinium chloride (GdnCl) (a) High temperature provides thermal energy greater than the strengths of the weak interactions (H-bonds, ionic interactions, hydrophobic forces, and van der Waals forces) and break these interactions. (b) Detergents (e.g., sodium dodecyl sulfate (SDS)) act primarily by disrupting the hydrophobic forces among nonpolar side chains that form the stable core of proteins (see below). (c) Extremes of pH alter the ionization states of acidic/basic groups of a protein, interrupting ( ) among them, and also disrupt some H-bonding. (d) From their structures, it is obvious that urea and GdnCl can form multiple ( ). They can sneak into protein interior and interrupt H-bond networks, often replacing water molecules. They also destroy hydrophobic forces that keep protein interior packed. Recall no water, no hydrophobic forces.