Concept explainers
For Problems 74 and 75, classify each of the numbered statements as (a) an experiment, (b) a hypothesis. (c) a scientific law, (d) an observation, or (e) a theory. (It is not necessary to understand the science involved to do these problems.)
75. Potassium bromate acts as a conditioner in dough made from wheat flour. Flour contains a protein called gluten. Proteins consist of amino-acid units linked in long chains. (1) Dough to which potassium bromate has been added rises better, producing a lighter, larger volume loaf. (2) Potassium bromate acts by oxidizing the gluten and cross-linking tyrosine (an amino acid) units of the protein molecules. enabling the dough to retain gas better. (3) A scientist wonders if sodium bromate might cross-link separate tyrosine molecules, forming a dimer (a molecule consisting of two subunits). (4) She adds sodium bromate to a solution of tyrosine. (5) She notes that a precipitate (solid falling out of solution) is formed.
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Chemistry for Changing Times, Books a la Carte Edition (14th Edition)
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