midterm_sample_short_answer

midterm_sample_short_answer - II Weak Forces 1 Explain the...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
II. Weak Forces 1. Explain the fact that ethanol (CH 3 CH 2 OH) is more soluble in water than is ethane (CH 3 CH 3 ). Ans: Ethanol can form hydrogen bonds with water molecules, but ethane cannot. When ethanol dissolves, the decrease in the system's entropy that results from formation of ordered arrays of water around the CH 3 CH 2 group is partly compensated by the favorable interactions (hydrogen bonds) of the hydroxyl group of ethanol with water molecules. Ethane cannot form such hydrogen bonds. III. Weak Acids and Bases 2. For each of the pairs below, circle the conjugate base. RCOOH RCOO RNH 2 RNH 3 + H 2 PO 4 H 3 PO 4 H 2 CO 3 HCO 3 Ans: RCOO , RNH 2 , H 2 PO 4 , HCO 3 3. You have just made a solution by combining 50 mL of a 0.1 M sodium acetate solution with 150 mL of 1 M acetic acid (p K a = 4.7). What is the pH of the resulting solution? Ans: pH = p K a + log [acid] base] [conjugate = 4.7 + log (5/150) = 4.7 – 1.48 = 3.22 V. Protein Purification 4. Salt fractionation separates proteins on the basis of _____________. Ans : Different solubilities of proteins in salt solutions. 5. Ion-exchange chromatography separates proteins on the basis of ______________. Ans : Different protein and bead (matrix/column) charge interactions.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
VI. Protein Sequencing 6. Why is it necessary to conduct the Edman degradation procedure multiple times to obtain a protein’s sequence? Ans : Cleavage or degradation of proteins into fragments results in loss of the information where each fragment is located in the original sequence. This can be recovered by sequence alignment of fragments from different degradation strategies.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 4

midterm_sample_short_answer - II Weak Forces 1 Explain the...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online