Nucleic acids, DNA and RNA, are polymers composed of nucleotide monomers.
Each nucleotide consists of a five-carbon sugar, a phosphate group, and a nitrogenous base.
DNA uses deoxyribose and bases adenine, thymine, guanine, and cytosine.
RNA uses ribose and replaces thymine with uracil.
DNA's structure is an antiparallel double helix with strands running in opposite 5’ to 3’ directions.
Adenine pairs with thymine, and cytosine pairs with guanine in DNA, while in RNA, adenine pairs with uracil.
The linear sequence of nucleotides has distinct ends: 3’ hydroxyl and 5’ phosphate.
During synthesis, nucleotides add to the 3’ end, forming covalent bonds.
The trap is overlooking the directionality of synthesis.
Confusing 3’ and 5’ ends leads to errors in predicting synthesis direction and strand orientation.
Structural differences matter: DNA is typically double-stranded, providing stability for genetic storage, while RNA’s single-stranded nature makes it versatile in functions like catalysis and protein synthesis.
Misunderstanding these roles leads to confusion about how genetic information is expressed and regulated.