6 5 Consider the weak acid H₂A and its conjugate base HA-. Which diagram below represents a buffer solution? Explain your 362 answer. A = H₁₂A Exploring General, Organic, & Biochemistry in the Laboratory B = HA-

MATHEMATICAL A catalog in the lab has a recipe for preparing 1 L of a TRIS buffer at 0.0500 M and with pH 8.0: dissolve 2.02 g of TRIS (free base, MW=121.1 g/mol) and 5.25 g of TRIS hydrochloride (the acidic form, MW=157.6 g/mol) in a total volume of 1 L. Verify that this recipe is correct.

A substance dissociates into K+ and Cl- in solution. The substance is a(n) ________. acid base salt buffer

Magnesium is an important element in the human body, especially in bones. Magnesiums atomic number is 12. Is it stable or reactive? Why? If it were to react with another atom, would it be more likely to accept or to donate one or more electrons?

A ________ can help keep the pH of a solution stable. a. covalent bond b. hydrogen bond c. buffer d. pH

MATHEMATICAL Sketch a titration curve for aspartic acid, and indicate the pKa values of all titratable groups. Also indicate the pH range in which the conjugate acid-base pair +1 Asp and 0 Asp will act as a buffer.

MATHEMATICAL Calculate the pH of a buffer solution prepared by mixing 75 mL of 1.0 M lactic acid (see Table 2.6) and 25 mL of 1.0 M sodium lactate.

MATHEMATICAL Show that, for a pure weak acid in water, pH=(pKa2log[HA])/2.

Aquaporins are proteins embedded in the plasma membrane that allow water molecules to move between the extracellular matrix and the intracellular space. Based on its function and location, describe the key features of the protein’s shape and the chemical characteristics of its amino acids.

Amino acids have the generic structure seen below, where R represents different carbon-based side chains. Describe how the structure of amino acids allows them to be linked into long peptide chains to form proteins.