Affinity chromatography is used to purify a protein of interest by capturing it on select one:

a. matrix material with a strongly interacting molecule (very high dissociation constant with target protein) attached.
b. matrix with very small pores that will only allow the protein of interest to pass.
c. matrix material with a strongly interacting molecule (very low dissociation constant with target protein) attached.
d. matrix material with molecules of opposite charge attached (relying on attraction between positive and negative charges).

c. matrix material with a strongly interacting molecule (very low dissociation constant with target protein) attached.

Explanation:

Affinity chromatography (AC) is based on the immobilization of the protein of interest inside of the column, by means of having a strongly interacting molecule in the matrix.

Strongly interacting means that the complex Protein-Interacting Molecule will not be easily dissociated, this translates into a low dissociation constant.

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

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