Draw the chemical structure of a dinucleotide composed of A and G. Opposite this structure, draw the dinucleotide composed of T and C in an antiparallel (or upside-down) fashion. Form the possible hydrogen bonds.

Verified step by step guidance

1. Start by drawing the backbone of the dinucleotide composed of adenine (A) and guanine (G). This includes the sugar-phosphate backbone, where each nucleotide is connected by a phosphodiester bond.
2. Draw the nitrogenous bases: adenine (A) and guanine (G). Adenine is a purine with a double-ring structure, and guanine is also a purine with a similar double-ring structure.
3. On the opposite side, draw the complementary dinucleotide composed of thymine (T) and cytosine (C) in an antiparallel orientation. This means the 5' end of one strand aligns with the 3' end of the other.
4. Draw the nitrogenous bases: thymine (T) and cytosine (C). Thymine is a pyrimidine with a single-ring structure, and cytosine is also a pyrimidine with a similar single-ring structure.
5. Indicate the hydrogen bonds between the bases: adenine pairs with thymine via two hydrogen bonds, and guanine pairs with cytosine via three hydrogen bonds.

Key Concepts

Dinucleotide Structure

A dinucleotide consists of two nucleotides linked by a phosphodiester bond. Each nucleotide is made up of a sugar, a phosphate group, and a nitrogenous base. In this case, the dinucleotide will include adenine (A) and guanine (G) for one strand, and thymine (T) and cytosine (C) for the complementary strand. Understanding the arrangement of these components is crucial for accurately drawing the chemical structure.

Antiparallel Orientation

In DNA, the two strands run in opposite directions, referred to as antiparallel orientation. This means that one strand runs from the 5' to 3' direction, while the complementary strand runs from 3' to 5'. This orientation is essential for the proper pairing of bases and the formation of hydrogen bonds, which stabilize the double helix structure of DNA.

Hydrogen Bonding

Hydrogen bonds form between complementary nitrogenous bases in DNA, specifically between adenine and thymine (A-T) and guanine and cytosine (G-C). A-T pairs form two hydrogen bonds, while G-C pairs form three. These bonds are crucial for the stability of the DNA structure and play a significant role in the base pairing mechanism, which is fundamental to DNA replication and transcription.