Final answer:
The true statement about tRNAs is that they are single-stranded molecules crucial for translating mRNA into proteins by carrying specific amino acids to the growing polypeptide chain. The correct option is B. tRNAs are single-stranded molecules.
Step-by-step explanation:
The correct statement about tRNAs is B. tRNAs are single-stranded molecules. Transfer RNAs (tRNA) play a crucial role in protein synthesis by functioning as adaptor molecules that read the information encoded in the messenger RNA (mRNA) and accordingly transfer the appropriate amino acid to the growing polypeptide chain.
tRNAs have a complex three-dimensional structure, typically depicted two-dimensionally as a cloverleaf, but in reality, they fold into an L-shaped structure. They are not made of DNA, do not carry mRNA to the ribosome, but have an anticodon loop that binds to the codons on the mRNA during translation process, guiding the incorporation of specific amino acids into the protein being synthesized.
C. tRNAs have an anticodon loop at one end.
Transfer RNAs (tRNAs) are RNA molecules that play a crucial role in protein synthesis. The correct option is C, as tRNAs have an anticodon loop at one end. The anticodon loop contains a sequence of three nucleotides that can base-pair with the complementary codon on mRNA during translation.
This interaction ensures the correct placement of amino acids in the growing polypeptide chain. tRNAs are not made up of DNA (option A), they are single-stranded molecules (option B), and they do not carry mRNA to the ribosome (option D).
The correct option is B. tRNAs are single-stranded molecules.