Mutations occur when in replication there is a variation in a nucleotide and therefore there is variation in a gene. Hence the importance of remembering the basics about nucleic acids • Complete the cards using the data in the box as clues. MRNA = linear, adenine, uracil, ribose, thymine, 2, 1, phosphoric acid (H₂PO₂), tRM = clover, deoxyribose, guanine, DNA replication and self-duplication, rRNA = globular, M-helix model, protein synthesis (translation), transcription, genetic material. Deoxyribonucleic acid DNA = Constituted by: Nitrogen bases: Pentose: Phosphate group: Source: Function: Number of chains: Shape: