Chapter 24, Problem 98A

Interpretation Introduction

Interpretation: The base pairing and its relation with the DNA structure are to be explained.

Concept introduction: Deoxyribonucleic acid (DNA) is made of two polynucleotide chains forming a double helix around each other. The two strands of DNA are held together by hydrogen bonding.

Answer to Problem 98A

Adenine with thymine, and cytosine with guanine, join to form complementary base pairs. These combinations are known as base pairing. These pairs of bases combine to form the double helix structure of DNA.

Explanation of Solution

Adenine (A), cytosine (C), guanine (G), and thymine (T) are the four nitrogen-containing bases. The bases adenine join with thymine, and cytosine joins with guanine to form complementary pairs. These pairs are referred to as base pairing.

The three building blocks of DNA are sugar, a phosphate group, and a nitrogen base. The base pairs form the double helix structure of DNA. The two helical strands are bonded together by hydrogen bonding formed between nitrogen bases.

The DNA helix structure is shown as follows:

  

Conclusion

Adenine with thymine, and cytosine with guanine, join to form complementary base pairs. These combinations are known as base pairing. These pairs of bases combine to form the double helix structure of DNA.