<span>Negatively charged R-groups in the primary structure.
This is because nickel acts as a cation, therefore you would be attracting anions, in this case it would be on the proteins that would be binding to the column. Once they bind to the matrix a was buffer of high salts can elute the proteins.</span>
You forgot to include the following choices but no worries I did this question before and the answers are:
advances in technology
increases understanding on environment
etc
Messenger RNA (mRNA) molecules carry the coding sequences for protein synthesis and are called transcripts; ribosomal RNA (rRNA) molecules form the core of a cell's ribosomes (the structures in which protein synthesis takes place); and transfer RNA (tRNA) molecules carry amino acids to the ribosomes during protein.
<span>Prokaryotic organisms are always unicellular, but eukaryotic organisms are always multicellular.
the second option because pro are usually found in plants and euk in animals and humans
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