Final answer:
tRNAs contain unusual bases such as dihydrouracil, pseudouridine, and inosine. These bases contribute to the structure and function of tRNA. The correct option is D.
Step-by-step explanation:
tRNAs (transfer RNAs) are small molecules that play a crucial role in protein synthesis by carrying the amino acids to the ribosome.
They contain some unusual bases, such as dihydrouracil, pseudouridine, and inosine. Dihydrouracil is found in the DHU arm of tRNA, while pseudouridine is found in the TYC arm. Inosine can be found at various positions in the tRNA molecule.
These unusual bases contribute to the structural stability and functionality of tRNA. For example, dihydrouracil helps in the recognition of the proper aminoacyl-tRNA synthetase, and pseudouridine is involved in the binding of aminoacyl-tRNA to the ribosomal surface.