Protein Synthesis From DNA

Card 1. What is the sequence and location of the promoter region where transcription begins?

AnswerThe TATA box, which has the sequence TATAAA, located 25 nucleotides upstream of the transcription start site.

Card 2. In what direction does RNA polymerase read the DNA template strand and synthesize mRNA?

AnswerIt reads the template strand in the 3' to 5' direction and synthesizes mRNA $in$ the 5' to 3' direction.

Card 3. What modifications are made to the ends of the pre-mRNA transcript after termination?

AnswerPoly-A polymerase adds a poly-A tail to the 3' end, and the 5' end is capped to prevent enzymatic degradation.

Card 4. What is the difference between introns and exons during pre-mRNA processing?

AnswerIntrons are non-coding nucleotide sequences removed during splicing, while exons are shorter coding sequences retained to build proteins.

Card 5. Given the DNA template strand 3' - G C A T A G T A T A C G - 5', what is the resulting mRNA transcript?

Answer5' - C G U A U C A U A U G C - 3'

Card 6. Which start codon initiates translation and which amino acid does it carry to the P site?

AnswerThe start codon is AUG, which pairs with the anticodon UAC carrying the methionine amino acid.

Card 7. What are the three active sites found within the ribosomal architecture during translation elongation?

AnswerThe E site, P site, and A site.

Card 8. What signals the termination of translation and what factor is recruited?

AnswerStop codons (UAA, UAG, UGA) enter the A site and recruit a release factor that disassembles the ribosomal subunits.