Question

Hydrogen bonds form between __ or __ and N or O on

the DNA ladder rungs, nitrogenous bases abbreviated A, C,
G, or T as in the diagram below:

Answer 1

Hydrogen bonds form between specific complementary nitrogenous bases, A-T and C-G, in the DNA double helix, with two bonds between A and T, and three bonds between C and G.

Step-by-step explanation:

Hydrogen bonds form between nitrogenous bases on the DNA ladder's rungs, which are the nucleotides abbreviated A, C, G, or T. These complementary base pairs are central to DNA's double helix structure. Adenine (A) always pairs with Thymine (T) through two hydrogen bonds, and Cytosine (C) bonds with Guanine (G) through three hydrogen bonds.

This specific pairing and the number of hydrogen bonds involved are critical because they ensure the uniformity of the double helix structure. The A-T pairs form two hydrogen bonds while C-G pairs form three, resulting in a stable and consistent DNA molecule. This characteristic pairing is important for DNA replication and its overall stability.

Answer 2

Hydrogen bonds in DNA form between specific nitrogenous bases, pairing adenine (A) with thymine (T) and cytosine (C) with guanine (G), to maintain the structure and stability of the DNA double helix.

Step-by-step explanation:

Hydrogen Bonds in DNA

Hydrogen bonds form between complementary nitrogenous bases within the DNA molecule, creating the steps of what can be visualized as a spiral staircase, known as the DNA double helix. In these hydrogen bonds, an adenine (A) base always pairs with a thymine (T), and a cytosine (C) pairs with a guanine (G). The bonding involves hydrogen attached to nitrogen or oxygen atoms, which interacts with nitrogen or oxygen on the complementary base. Specifically, there are two hydrogen bonds between A and T, and three hydrogen bonds between C and G.

The consistency in the base pairing is crucial for maintaining the structure of DNA. Adenine and guanine have a two-ring structure while cytosine and thymine have a single-ring structure, which pairs perfectly to maintain the uniform shape of the DNA molecule. The bonds between the nitrogenous bases are not only essential for the structure but also for the stability of the DNA molecule, ensuring it can replicate and perform its functions in the cell effectively. During DNA replication or biotechnological processes such as PCR (Polymerase Chain Reaction), these hydrogen bonds can be disrupted and then reformed, which is essential for the denaturation and renaturation processes.