Question

Which of the following statements about mature tRNA and/or mRNA are FALSE?

• A. tRNAs end with CCA sequence at the 3' end
• B. Both form clover-leaf structures
• C. Both are polyadenylated at their 3' ends
• D. All tRNAs are devoid of introns

Hint:

While mRNA is polyadenylated at its 3' end for stability and translation regulation, tRNAs do not undergo this modification and serve a different role in protein synthesis.

Answer 1

The Correct Option is B, C, D

Step 1: Understanding tRNA and mRNA.
tRNA molecules are involved in protein synthesis by carrying amino acids to ribosomes. They are characterized by a CCA sequence at the 3' end, which is essential for amino acid attachment. mRNA carries the genetic code from DNA to the ribosome for protein synthesis.

Step 2: Analyzing the options.
(A) tRNAs end with CCA sequence at the 3' end: This is correct. The CCA sequence is essential for the function of tRNA molecules.
(B) Both form clover-leaf structures: This is correct. Both tRNA and some forms of mRNA exhibit secondary structures such as clover-leaf.
(C) Both are polyadenylated at their 3' ends: This is incorrect. mRNA molecules are typically polyadenylated at their 3' end, but tRNA molecules are not.
(D) All tRNAs are devoid of introns: This is correct. tRNAs do not contain introns, as they are small and involved in the translation process.

Step 3: Conclusion.
The correct answer is (C) Both are polyadenylated at their 3' ends, as tRNAs are not polyadenylated, unlike mRNA.