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Count the number of each of the following characteristics for this double-stranded piece of DNA?

a.3’-ATAATATTAGAATTAAATATTACGGGTTGTGAT-5’
b.5’-TATTATAATCTTAATTTATAATGCCCAACACTA-3’
c.phosphodiester bonds
d.pyrimidines
e.hydrogen bonds
f.ribose sugars
g.3' hydroxyl (OH) groups

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Final answer:

The double-stranded DNA molecule consists of 34 phosphodiester bonds per strand (68 total), 28 total pyrimidines, 57 hydrogen bonds, 70 deoxyribose sugars, and 2 total 3' hydroxyl (OH) groups as there's one at the end of each strand.

Step-by-step explanation:

When we examine the double-stranded DNA molecule provided by the student, we can identify the various characteristics by understanding the structure of DNA.

  • Phosphodiester bonds are the covalent bonds that connect the phosphate group of one nucleotide to the 3' hydroxyl group of another nucleotide's sugar in the DNA backbone. Since we have a linear sequence of complementary strands, there will be one less phosphodiester bond than nucleotides in each strand, resulting in 34 bonds per strand or 68 total for the double-stranded DNA.
  • Pyrimidines are the nitrogenous bases cytosine and thymine in DNA. Counting the cytosines and thymines in both strands gives a total of 28 pyrimidines.
  • Hydrogen bonds form between the complementary bases: adenine-thymine pairs have two hydrogen bonds, and guanine-cytosine pairs have three. Counting all the complementary base pairs, we calculate a total of 57 hydrogen bonds.
  • Ribose sugars are a misnomer in this context since DNA contains deoxyribose sugars, not ribose. Each nucleotide has one deoxyribose sugar, so there are 35 sugars per strand or 70 in the double-stranded DNA.
  • The 3' hydroxyl (OH) groups can be found at the 3' end of each DNA strand, so there are 2 in total.

It is essential to be familiar with these DNA characteristics to understand its form and function, as well as to accurately count these molecular features.

User Umer Abbas
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