Single strands of nucleic acids are directional, meaning that there are two different ends. What functional groups define the two different ends of a strand?

Verified step by step guidance

1. Identify the structure of nucleic acids: Nucleic acids, such as DNA and RNA, are polymers made up of monomer units called nucleotides. Each nucleotide consists of a phosphate group, a sugar (deoxyribose in DNA and ribose in RNA), and a nitrogenous base.
2. Understand the composition of the backbone: The backbone of a nucleic acid strand is formed by alternating phosphate and sugar groups. The phosphate group of one nucleotide connects to the sugar of the next nucleotide through phosphodiester bonds.
3. Recognize the directionality of nucleic acids: Nucleic acid strands have directionality due to the orientation of the sugar-phosphate backbone. One end of the strand has a free phosphate group attached to the 5' carbon of the sugar, known as the 5' end.
4. Identify the 3' end: The other end of the strand has a free hydroxyl group (-OH) attached to the 3' carbon of the sugar, known as the 3' end.
5. Summarize the functional groups: The two different ends of a nucleic acid strand are defined by the presence of a phosphate group at the 5' end and a hydroxyl group at the 3' end.

Key Concepts

Nucleic Acid Structure

Nucleic acids, such as DNA and RNA, are polymers made up of nucleotide monomers. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base. The sugar-phosphate backbone forms the structural framework of the nucleic acid, with the sequence of nitrogenous bases encoding genetic information.

5' and 3' Ends

The terms 5' (five prime) and 3' (three prime) refer to the orientation of the sugar molecule in the nucleotide. The 5' end has a phosphate group attached to the fifth carbon of the sugar, while the 3' end has a hydroxyl group attached to the third carbon. This directional property is crucial for processes like DNA replication and transcription.

Functional Groups

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. In nucleic acids, the phosphate group at the 5' end and the hydroxyl group at the 3' end are key functional groups that define the polarity and reactivity of the nucleic acid strand.