The blank spaces can be filled by the following:
sugar-phosphate backbones
nucleotide base pairs
amino acids
hydrogen bonds
What is protein?
The protein appears to have regions that are closely associated with the region between the two sugar-phosphate backbones of the DNA double helix, thus nestled against the nucleotide base pairs It is likely that amino acids in these regions of the protein are uniquely suited for binding through weak interactions like hydrogen bonds and van der Waals forces) with specific nucleotide sequences, thus recognizing them specifically.
Proteins are complex molecules made of amino acids, essential for cell structure and function, supporting growth, repair, and various biological processes.