Question

3' AAA TGC GCG ATA 5' is the sequence of nucleotides on a gene; after transcription the mRNA formed against it and the sequence of bases in the corresponding binding anticodons will be
a. 5’UUU ACG CGC UAU 3' and 3’ AAA UGC GCG AUA 5’
b. 5' UAU CGC GCA UUU 3' and 3' AUA GCG CGU AAA 5’
c. 5' UUU ACC TUG UAU 3' and 3’ AAA UGG UAC AUA 5’
d. 5’UAU GUT CCA UUU 3' and 3’AUA CAU GGU AAA 5’

Answer 1

Hint: The Gene is nothing but DNA, and RNA, where they are called as nucleic acids and are made up of nucleotides which are structural unit of the genes, and the nucleotide is the compound where it contains 3 structures such as nitrogen base, phosphate and carbon atom, if this compound do not phosphate attached to it, then it is called as nucleoside.

Complete answer:
- Nitrogen bases that are present in the nucleic acids are divided into 2 types, they are purines and pyrimidines.
- The Purines are Adenine and guanine while the Pyrimidines are Thymine and Cytosine.
- But in the RNA, thymine is absent instead of containing Uracil.
- The Purines and Pyrimidines that are present in the DNA, and RNA are complementary to each other where in the DNA, Adenine and thymine are complementary base pairs, where Cytosine and guanine are complementary to each other, in RNA it is same except for Adenine is complementary to uracil.
- In the above question the sequence given are 3' AAA TGC GCG ATA 5', and they said that transcription takes place where transcription is the process of forming mRNA from the DNA that takes place in the nucleus and carried out to the cytoplasm.
- So the sequence of the mRNA that is formed to the given sequence of the DNA are
3' AAA TGC GCG ATA 5'
5’UUU ACG CGC UAU 3’ so the main difference here is instead of thymine uracil is formed complementary to Adenine.

- At the same time they asked about the sequence of binding anticodons to the formed mRNA are,
3' AAA TGC GCG ATA 5' -- DNA sequence given
5’UUU ACG CGC UAU 3’--mRNA formed from DNA
3’ AAA UGC GCG AUA 5’---Anticodons bind to mRNA.

Hence, the correct answer is option (A).

Note: During transcription the strand of DNA from which complementary base pairs of the mRNA are formed are called as template strand and the reading is always takes place in 3’ to 5’ direction, and coding of mRNA is takes place from 5’ to 3’ direction.