Capping and Tailing

Q.

What is the difference between monocistronic and polycistronic?

Q. In a post-transcriptional modification called tailing, ____ residues are added at the ____ of mRNA.

1. adenylate, 5'-end
2. guanylate, 3'-end
3. adenylate, 3'-end
4. guanylate, 5'-end

Q. What are the functions of (i) methylated guanosine cap, (ii) poly-A “tail” in a mature on RNA?

Q. Capping and tailing are carried out on mRNAs to

1. Ensure protection from ribonucleases
2. Ensure attachment to ribosomes for translation
3. Ensure ease of transportation and identification
4. All of the above.

Q. RNA splicing will lead to the joining of:

1. non-coding sequences
2. exons
3. hnRNAs
4. introns

Q. Given below is a heterogeneous RNA formed during eukaryotic transcription.


How many introns and exons respectively are formed in this hnRNA?

1. 8, 8
2. 7, 7
3. 8, 7
4. 7, 8

Q.

Are introns non-coding?

Q. In mRNA, AUG is the initiation codon and UAA, UAG and UGA are termination codons, therefore polypeptide cannot be synthesized beyond any of these triplets to the end of mRNA. Then which one of the following mRNA can be translated completely?

1. AUC ACG UAU UUC UGA CUC
2. AUG UAU UUC UGC CUC UAG
3. AUG UUC UCC UGG UAA UAU
4. AUG UUC UCC UGA UGG UAU

Q. Which of the following is initiation codon?

1. UAG
2. AUC
3. AUG
4. CCU

Q. What is meant by capping and tailing?

Q. hnRNA undergoes two additional processes. In one of the process, an unusual nucleotide (methyl GPT) is added to the 5' end of the molecule. What would you call this?

1. Splicing
2. Tailing
3. Termination
4. Capping

Q. On which strand of DNA, mRNA is constructed?

1. Sense strand
2. Antisense strand
3. Both the strand
4. Any one strand

Q. Capping and tailing are carried out on mRNAs to

1. Ensure protection from ribonucleases
2. Ensure attachment to ribosomes for translation
3. Ensure ease of transportation and identification
4. All of the above.

Q. Assertion :

The uptake of DNA during transformation is an active, energy requiring process.

Reason: Transformation occurs in only those bacteria, which possess the enzymatic machinery involved in the active uptake and recombination.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. mRNA undergoes two additional processing steps. Out of which, in one of them an unusual nucleotide (methyl guanosine triphosphate) is added to the 5' end of mRNA. This is known as

1. Capping
2. Tailing
3. Splicing
4. Termination

Q. All of the following is present in a molecule of messenger RNA except

1. Ribose
2. Phosphate
3. Adenine
4. Cytosine
5. Thymine

Q.

Is ATG a start codon?

Q. Capping and tailing are carried out on mRNAs to

1. Ensure protection from ribonucleases
2. Ensure attachment to ribosomes for translation
3. Ensure ease of transportation and identification
4. All of the above.

Q. Assertion :Amber codon is a termination codon. Reason: If in an mRNA, a termination codon is present, the protein synthesis stops abruptly whether the protein synthesis is complete or not.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
3. Assertion is correct but Reason is incorrect.
4. Both Assertion and Reason are incorrect.

Q. mRNAs are capped by

1. Modified GTP at the 3’ end and modified ATP at the 5’ end
2. Modified Poly G tail at the 3’ end and ATP at the 5’ end
3. Modified GTP at the 5’ end and Poly A tail at the 3’ end
4. Modified GTP at the 3’ end and Poly A tail at the 5’ end

Q. Identify A, B, C and D in the given diagram of mRNA

1. A - Methylated cap B - Non-coding region C - Coding region D - Poly A tail
2. A - Poly A tail B - Termination codon C - Initiation codon D - Methylated cap
3. A - Methylated cap B - Coding region C - Non-coding region D - Poly A tail
4. A - Methylated cap B - Initiation codon C - Termination codon D - Poly A tail

Q. Assertion :mRNA attaches to ribosome through its 3' end. Reason: The mRNA has F-capsular nucleotide and bases of lagging sequence.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
3. Assertion is correct but Reason is incorrect.
4. Both Assertion and Reason are incorrect.

Q.

How is the translation of mRNA terminated? Explain.

Q. mRNA undergoes two additional processing steps. Out of which, in one of them an unusual nucleotide (methyl guanosine triphosphate) is added to the 5' end of mRNA. This is known as

1. Tailing
2. Splicing
3. Termination
4. Capping

Q. mRNA undergoes two additional processing steps. Out of which, in one of them an unusual nucleotide (methyl guanosine triphosphate) is added to the 5' end of mRNA. This is known as

1. Capping
2. Tailing
3. Splicing
4. Termination

Q. mRNAs are capped by

1. Modified GTP at the 3’ end and modified ATP at the 5’ end
2. Modified GTP at the 5’ end and Poly A tail at the 3’ end
3. Modified GTP at the 3’ end and Poly A tail at the 5’ end
4. Modified Poly G tail at the 3’ end and ATP at the 5’ end

Q. A distinct mechanism that usually involves a short segment of DNA with remarkable capacity to move from one location in a chromosome to another. What is this called as?

1. DNA replication
2. DNA hybridization
3. DNA transposition
4. DNA recombination

Q. Transcription involves

1. Synthesis of RNA over DNA
2. Joining of amino acids in a polypeptide
3. Synthesis of RNA over ribosome
4. Synthesis of DNA

Q.

Name the enzyme that catalyses the transcription of hnRNA.

(ii) Why does the hnRNA need to undergo changes ? List the changeshnRNA undergoes and wher e in the cell such changes take pl ace.

Q. The direction of eukaryotic transcription is