Question

Find the prokaryotic promoter sequences; Draw boxes around them, Circle the start codon. Then transcribe the following DNA sequence correctly into mRNA and translate it into the correct protein sequence.
a. 5’CATTGACAGCTTGATGACAGATGCAGTATAATGCGATTAGCTATGACGGACGTAGCTAGCAGCTGACGCCAGGCTT

b. 3’GTAACTGTCGAACTACTGTCTACGTCATATTACGCTAATCGATACTGCCTGCATCGATCGTCGACTGCGGTCCGAA

Answer 1

Explanation:

The transcription is a process which transcribe the DNA into a molecule which could be read by the machinery to translate it into the proteins and that molecule is known as the mRNA molecule.

1.The mRNA molecule is transcribed by an enzyme called RNA polymerase which transcribe DNA in 5'to 3'direction that is DNA strand will be 3' to 5'direction therefore the strand with 3' to 5' will act as template strand.

2. The RNA polymerase binds at promoter region and there are two sequences in prokaryotes at -35 end which is TTGACA and at -10 end which is TATAAT.

3. The translation begins after the start codon which is AUG therefore proteins will be synthesized after AUG.

In the given question, both promoter sequence are present in the 5'to 3'strand

3’GTAACTGTCGAACTACTGTCTACGTCATATTACGCTAATCGATACTGCCTGCATCGATCGTCGACTGCGGTCCGAA

The mRNA will be -

5'- CAUUGACAGCUUGAUGACAGAUGCAGUAUAAUGCGAUUAGCUAUGACGGACGUAGCUUAGCAGCUGACGCCAGGCUU-3'.

There are two start codon thus two polypeptides will be synthesized.

1. met-thr-asp-ala-val

2. met-thr-asp-val-ala-ser-ser