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1. Select the answer that corresponds to the statement that is true. If a crysta

ID: 189152 • Letter: 1

Question

1.

Select the answer that corresponds to the statement that is true.

If a crystal of pure -D-galactose is dissolved in water and left in solution for a long period of time, which of the following will also be present in the solution?

(i) -L-galactose; (ii) -L-galactose; (iii) -D-galactose; (iv) the open chain form of D-galactose; (v) the open chain form of L-galactose; (vi) D-mannose

(i) and (ii)
(i)
(iii) and (iv)
(v)
(vi)

2. True or false?

True False  In "Western blotting", a fluorescently tagged antibody specific for a protein of interest is first added to a cell extract, after which the extract is separated by SDS-polyacrylamide gel electrophoresis, and the antibody-antigen complex detected because of its fluorescence.
True False  Polyclonal antibodies are mixtures of antibodies that each recognize different surface features (or epitopes) on a protein antigen.
True False  SDS can be added prior to gel electrophoresis to reduce disulfides in the proteins.
True False  Protein structures obtained by X-ray crystallography are likely to represent the native structure of the protein in the cell because much of the crystal volume between the proteins is filled with water molecules.
True False  The anomeric carbon in both glucopyranose and fructofuranose is C1.

Explanation / Answer

2. The statement about western blotting is true.

The statement about polyclonal antibody is True. This antibody each recognizes a different epitope on a protein.

Statement of SDS gel electrophoresis is true.

X-ray crystallography can produce molecular structure protein. So the statement is false.