In: Biology
1. Which DNA sequence is recognized first to initiate transcription in eukaryotes?
A. TATA box
B. poly A sequence
C. coding sequence
D. enhancer
2. Strand initiation in DNA replication is accomplished when the enzyme primase lays down a primer. In prokaryotes, of what molecule is that primer composed?
A. DNA
B. RNA
C. protein
D. lipid
1. TATA box is the DNA sequence that is recognized first to initiate transcription in eukaryotes. on the other hand, six nucleotides long Pribnow box is the sequence that is recognized first to initiate transcription in prokaryotes. The TATA box does not code for a protein sequence. Hence, it is a non-coding sequence. During the synthesis of mRNA, the poly-A tail is added to the 3' end of pre mRNA. poly-A sequence is a sequence at which cleavage before the addition of the poly-A nucleotides is done. The coding sequence is the sequence that codes for the protein. The enhancer is the sequence at which activators bind to increase the rate of transcription.
2. Primer is composed of RNA in both prokaryotes and eukaryotes. Primer is a small RNA sequence synthesized by primase. Primer is required for strand initiation in DNA replication as DNA polymerase cannot synthesize DNA from the starting. It can only add nucleotides to the RNA primer existing on DNA template strand.