Intermediate Topic 830 of 1102 Organic Chemistry
Nucleic Acid Structure
DNA and RNA are polymers of nucleotides containing sugar, phosphate and base.
In-depth explanation of Nucleic Acid Structure
Nucleic acids are polymers of nucleotides, each made of a nitrogenous base, a pentose sugar and a phosphate group, linked by phosphodiester bonds. DNA contains the sugar deoxyribose and the bases adenine, thymine, guanine and cytosine, and it usually forms a double helix in which the two strands are held together by hydrogen bonds between complementary base pairs. RNA contains ribose and uracil in place of thymine and is usually single stranded. The sugar-phosphate backbone is what gives nucleic acids their directionality, written from the 5 prime to the 3 prime end.
Going deeper: Nucleic Acid Structure
Key ideas: A nucleotide is base plus pentose sugar plus phosphate: ribose in RNA, deoxyribose in DNA. Bases: purines (A, G, two rings) and pyrimidines (C, T in DNA, U in RNA, one ring). Chargaff rules: A equals T and G equals C in DNA. A-T pairs have two hydrogen bonds, G-C three. The strands are antiparallel and wind in a double helix with a 3.4 nm pitch per 10 base pairs, linked by 3 to 5 phosphodiester bonds.
Common mistakes and connections: Students put uracil in DNA or think RNA is double-stranded. Another error is forgetting direction: 5 prime to 3 prime. Higher G-C content raises melting temperature. Links to phosphate esters, hydrogen bonding and protein synthesis (transcription, translation).
Visualization of Nucleic Acid Structure
Two antiparallel nucleotide strands wind into the double helix, held by hydrogen bonds between A-T and G-C base pairs. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Chargaff's rules state that in DNA the amount of adenine equals thymine and the amount of guanine equals cytosine.
Frequently asked questions about Nucleic Acid Structure
What is Nucleic Acid Structure?
DNA and RNA are polymers of nucleotides containing sugar, phosphate and base.
Is Nucleic Acid Structure a beginner, intermediate or advanced topic?
Nucleic Acid Structure is a intermediate topic in Organic Chemistry. It builds on the vocabulary of beginner topics in this area.
What should I learn before Nucleic Acid Structure?
Study these earlier topics in Organic Chemistry first: Zwitterions, Peptide Bond, Lipids.
What comes after Nucleic Acid Structure?
The next topics in Organic Chemistry are Polymers Overview and Addition Polymers.
Can I practise Nucleic Acid Structure with quizzes?
Yes. The interactive lesson includes a self-check question on Nucleic Acid Structure, and the Organic Chemistry quiz draws on every topic in this area.
Where Nucleic Acid Structure fits in Organic Chemistry
Nucleic Acid Structure is topic 102 of 148 in Organic Chemistry.