Study Questions for Week 1

Study Questions for Week 1 - a , you must convert it to the...

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STUDY QUESTIONS FOR WEEK 1: 1. What are the defining characteristics of prokaryotic and eukaryotic cells? 2. Biochemistry has shown that humans, yeast, and plants are actually quite similar despite vast differences in outward appearance. What is this based on? 3. Draw a hydrogen bond that is present in the cell? Which is the donor? Which is the acceptor? 4. Explain how van der Waals interactions can be called a “team effort”. 5. Draw the van der Waals interaction graph and note the van der Waals contact distance. 6. Discuss how the various bonds/interactions discussed in lecture take part in the structure of DNA double helix. 7. What are the various methods to denature and anneal two strands of complementary DNA? 8. Derive the Henderson-Hasselbalch equation. 9. A buffer is prepared containing 1.00 M acetic acid and 1.00 M sodium acetate. What is its pH? We must know the pK a of acetic acid. Most times, the problem will provide the pK a . If the problem provides the K
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Unformatted text preview: a , you must convert it to the pK a . The K a of acetic acid is 1.77 x 10 5 pK a = - log K a = - log 1.77 x 10 5 = 4.752 Next, we simply insert the appropriate values into the H-H equation: pH = 4.752 + log (1.00 / 1.00) Since the log of 1 is zero, we have pH = 4.752 10. Find the pH of 1.25 M acetic acid and 0.75 M potassium acetate. Acetic acid Ka = 1.74 E-5 pKa = 4.76. pH = pKa log [(HA) / (A)] pH = 4.76 log [1.25 / 0.75] pH = 4.76 0.222 pH = 4.5 11. Calculate the pH of a buffer solution made from 0.20 M HC 2 H 3 O 2 and 0.050 M C 2 H 3 O 2-that has an acid dissociation constant for HC 2 H 3 O 2 of 1.8 x 10-5 . Solve this problem by plugging the values into the Henderson-Hasselbalch equation for a weak acid and its conjugate base. pH = pK a + log ([A-]/[HA]) pH = pK a + log ([C 2 H 3 O 2-] / [HC 2 H 3 O 2 ]) pH = - log (1.8 x 10-5 ) + log (0.050 M / 0.20 M) pH = - log (1.8 x 10-5 ) + log (0.25) pH = 4.7 - 0.6 pH = 4.1...
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Study Questions for Week 1 - a , you must convert it to the...

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