Open Question
What are the names of the sugars in DNA and RNA, and how do they differ?
Ch.23 - Organic and Biological Chemistry
Chapter 23, Problem 131
The DNA from sea urchins contains about 32% A and about 18% G. What percentages of T and C would you expect in sea urchin DNA? Explain.
Verified step by step guidance1
Step 1: Understand the base pairing rules in DNA. Adenine (A) pairs with Thymine (T), and Guanine (G) pairs with Cytosine (C). This means the percentage of A should equal the percentage of T, and the percentage of G should equal the percentage of C.
Step 2: Given that the DNA contains 32% A, use the base pairing rule to determine the percentage of T. Since A pairs with T, the percentage of T should also be 32%.
Step 3: Calculate the total percentage of A and T in the DNA. Since both A and T are 32%, add these percentages together: 32% + 32% = 64%.
Step 4: Determine the remaining percentage of the DNA that is composed of G and C. Since the total percentage of all bases in DNA must equal 100%, subtract the percentage of A and T from 100%: 100% - 64% = 36%.
Step 5: Use the base pairing rule to find the percentage of C. Given that G is 18%, and G pairs with C, the percentage of C should also be 18%. Verify that the sum of G and C equals the remaining percentage: 18% + 18% = 36%.
Related Practice
Open Question
Show by drawing structures how the phosphate and sugar components of a nucleic acid are joined.
Open Question
Show by drawing structures how the sugar and nitrogenous base components of a nucleic acid are joined.
Open Question
Fumaric acid is an organic substance widely used as a food additive. Its elemental composition is 41.4% C, 3.5% H, and 55.1% O. A solution made by dissolving 0.1500 g of fumaric acid in water and diluting to a volume of 100.0 mL gave rise to an osmotic pressure of 240.3 mm Hg at 298 K. On titration of a sample weighing 0.573 g, 94.1 mL of 0.105 M NaOH was required to reach an equivalence point. Fumaric acid reacts with 1 mol of H2 to give a hydrogenation product. (a) What is the empirical formula of fumaric acid? (b) What is the molecular weight of fumaric acid? (c) Draw three possible structures for fumaric acid. (d) If fumaric acid contains a trans double bond, which of your structures is correct?
Open Question
Cytochrome c is an important enzyme found in the cells of all aerobic organisms. Elemental analysis of cytochrome c shows that it contains 0.43% iron. What is the minimum molecular weight of this enzyme?
Textbook Question
Cyclohexane, C6H12, is an important starting material used in the industrial synthesis of nylon. Each carbon has four covalent bonds, two to hydrogen and two to other carbons. Draw the structural formula of cyclohexane.
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