Question

The DNA double helix is composed of two single-stranded DNA molecules. Which of the following statements is accurate when considering how the two single-stranded DNA molecules interact with each other (interstrand) and how the nucleotides interact within the same strand (intrastrand)? At both the interstrand and intrastrand level, nucleotides interact via covalent bonds. At the intrastrand level, nucleotides interact via phosphodiester bonds, while at the interstrand level, nucleotides interact via hydrogen bonds. At the intrastrand level, nucleotides interact via hydrogen bonds, while at the interstrand level, nucleotides interact via covalent bonds. At the intrastrand level, nucleotides interact via hydrogen bonds, while at the interstrand level, nucleotides interact via phosphodiester bonds. Antiparallel DNA strands interact only during replication.

Answer 1

At the intrastrand level, nucleotides interact via phosphodiester bonds, while at the interstrand level, nucleotides interact via hydrogen bonds

Step-by-step explanation:

Deoxyribonucleic acid, also called DNA, is a double helical structure composed of two polynucleotide chains. Each of these chains is called a STRAND. Each strand is made up of nucleotide subunits containing a phosphate group, a pentose sugar and a nitrogenous base (Adenine, Guanine, Cytosine and Thymine).

Within the strand (intrastrand), the 5' phosphate group of one nucleotide subunit is joined to the 3' OH group of another nucleotide by a form of covalent bond called PHOSPHODIESTER BOND. This continuously forms the long polynucleotide chain that makes up a strand of DNA.

However, between the two strands (interstrand), the base of one strand is held to the complementary base of another strand by HYDROGEN BONDS. This forms the double-stranded molecule we are familiar with.