Share
Explore BrainMass

Transcription

1. What sequence of nucleotide pairs in a Drosophila gene will encode the amino acid sequence met-trp-phe-trp-met (reading from the amino terminus to the carboxyl terminus)?

2. A wild type gene contains the trinucleotide-pair sequence:
was 5'-GAG-3' changed to:5'-GTG-3'
3'CTC -5' 3'-CAC-5'
If the second base pair in this gene segment will change from A-T to T-A, will it still code the glutamic acid?

3. A single nucleotide addition followed by a single nucleotide deletion approximately 20 bp apart in the DNA causes a change in the protein sequence from

-His-Thr-Glu-Asp-Trp-Leu-His-Gln-Asp-

to -His-Asp-Arg-Gly-Leu-Ala-Thr-Ser-Asp-

Which nucleotide has been added and which deleted? What are the original and the new mRNA sequences?

Solution Preview

1. What sequence of nucleotide pairs in a Drosophila gene will encode the amino acid sequence met-trp-phe-trp-met (reading from the amino terminus to the carboxyl terminus)?

Response:

All you need to do is look up the codons on the chart and write them down in order, like this:

met--trp--phe--trp--met
ATG-TGG-TTT-TGG-ATG

(If you wanted, you could have had another triplet for phe.

Therefore, the sequence is:
ATGTGGTTTTGGATG

===============================================

2. A wild type gene contains the trinucleotide-pair sequence:

was 5'-GAG-3' changed to:5'-GTG-3'
3'-CTC-5' 3'-CAC-5'

If the second base pair in this gene segment will change from A-T to T-A, will it still code the glutamic acid?

Response:

All you need to do is ...

$2.19