In a transcription unit, the promoter is located towards which end of the coding strand?
The promoter is located at the 5-prime end (upstream) of the structural gene with reference to the coding strand polarity.
Question 552 of 668
📘 CLASS XII
Which factor binds to RNA polymerase to initiate transcription in prokaryotes?
The Sigma factor binds transiently to the core RNA polymerase enzyme to recognize the promoter and initiate transcription.
Question 553 of 668
📘 CLASS XII
Which RNA polymerase in eukaryotes is responsible for transcribing hnRNA (precursor to mRNA)?
In eukaryotes, RNA Polymerase II transcribes the precursor of mRNA, which is called heterogeneous nuclear RNA (hnRNA).
Question 554 of 668
📘 CLASS XII
What is the function of RNA Polymerase I in eukaryotes?
RNA Polymerase I transcribes the large ribosomal RNAs: 28S, 18S, and 5.8S rRNA. (Mnemonic: RMT -> I, II, III).
Question 555 of 668
📘 CLASS XII
Splicing is the process of removal of _______ and joining of _______.
Splicing involves the removal of non-coding sequences called introns and the joining of coding sequences called exons to form mature mRNA.
Question 556 of 668
📘 CLASS XII
In capping, which unusual nucleotide is added to the 5-prime end of hnRNA?
During processing, a cap consisting of 7-methyl guanosine triphosphate is added to the 5-prime end of the hnRNA.
Question 557 of 668
📘 CLASS XII
Which scientist proposed that the genetic code is a triplet?
Physicist George Gamow argued that since there are 4 bases and 20 amino acids, the code must constitute a combination of at least 3 bases (4^3 = 64) to code for all amino acids.
Question 558 of 668
📘 CLASS XII
Who synthesized RNA molecules with defined combinations of bases (homopolymers/copolymers) to decipher the genetic code?
Har Gobind Khorana developed a chemical method to synthesize RNA molecules with defined base combinations (like UUUUU... or UGUGUG...) to help decipher the genetic code.
Question 559 of 668
📘 CLASS XII
The codon AUG has dual functions. It codes for _______ and acts as an _______ codon.
AUG is the start or initiator codon and specifically codes for the amino acid Methionine.
Question 560 of 668
📘 CLASS XII
The property of the genetic code where one amino acid is coded by more than one codon is called?
Degeneracy refers to the fact that some amino acids are coded for by more than one triplet codon (e.g., Serine has 6 codons).
