Question

d. glycosidic bonds e. Both a and care correct answers. 05. If a portion of a messenger RNA molecule contains the base sequence 5'-A-A-U-3', the corresponding transfer RNA base sequence is a. 5'-A-A-U-3 b. 5-G-G-T-3 C. 5-T-T-C-3' 5-U-U-A-3 e. 5-A-U-U-3 06. What is the role of tRNA during translation? a. To disrupt the DNA helix to allow RNA polymerase to copy the template strand. (b. To carry ribosomes to the site of protein synthesis. c. To recognize stop codons. d. To carry amino acids to the mRNA for correct placement into the polypeptide chain. e. Both c and d are correct answers.

Answer 1

5. The corresponding t - RNA base sequence is 5'-U-U-A-3'

Loops are present in the structure of t-RNA ,where hydrogen bonds are not formed. One of them is recognition loop,the most specific loop. t-RNA are different due this loop. A specific sequence of 3 nucleotides is present at the end of this loop. It is known as Anticodon. There are total 61 types of anticodon that means 61 types of t-RNA. t-RNA recognizes its place on m-RNA with the help of anticodon by recognizing its complementary sequence on m-RNA ,known as codon. UUA is complementary to AAU.

6. The role of tRNA during translation is to carry amino acids to the mRNA for correct placement into the polypeptide chain.

DHU loop of tRNA helps to recognize specific aminoacyl synthetase enzyme which activates specific amino acids and attach it to the 3' end of tRNA ,also known as acceptor arm. There are total 20 amino acids and tRNA are specific for each amino acid. tRNA carries amino acid to the mRNA according to the codon and then polypeptide bonds are formed.

Stop codon are 3 in number UAA, UAG, UGA. They are recognized by termination factors or release factors. No tRNA is able to recognize stop codons by their anti codons.

Protein synthesis occurs on ribosomes in the cytoplasm. Disruption of DNA helix during transcription is done by the enzyme which breaks the hydrogen bonds between two strands.

& Acceptoram Lovр С——От че ОНО Loop Тоор & Recognition loop I & Anticodon

) Amino acid VUA AAU MARNA