a) Scientists genetically engineered some fish so they contained a green fluores
ID: 277050 • Letter: A
Question
a) Scientists genetically engineered some fish so they contained a green fluorescent protein (gfp) gene that made them glow green. They introduced the gene construct shown below into freshly fertilised egg cells promoter and regulatory region gfp coding sequence ATG TAG (1) What is a 'coding sequence' and what is the role of the ATG and TAG sequences shown? (2 marks) () The scientists wanted the fish to express the gfp gene and glow green only when they are in water contaminated with heavy metals, so they could use them as pollution indicators. How could they do this? (2 marks) (ii) As a control the scientists wanted to engineer other fish that expressed the gfp (2 marks) gene and glowed green all the time. How could they do this? (iv) Would you expect every cell in the genetically engineered fish to contain the gfp gene? Give a reason for your answer. (2 marks) (v) Describe a method the scientists could use to confirm that the modified fish contain the gfp gene. (2 marks)Explanation / Answer
I) The coding sequence is a part of DNA which transcribed into mRNA, which upon modifications translated into a functional peptide. Briefly, a coding region is a part of DNA which codes for protein. The complementary sequences of ATG and TAG are AUG and UAG which are the start and stop codons for the gene. That means the DNA sequence between these two codons indicates the coding region.
2)If scientists wanted to use GFP protein as an indicator for heavy metal contamination, they need to insert this GFP gene attached to the heavy metal processing enzyme-coding genes under enzymes promoter control, so that if heavy metal is accumulated in the fish, it will start Xenobiotic reactions under specific enzyme missionary. the expression of this enzyme leads to co-expression of GFP protein which produces a green colour fluorescence.
3) If scientists need to express GFP protein in fish all the time then they need to join a strong promoter to the coding region of GFP protein. The strong promoter makes the RNA polymerase missionary to identify them continuously so that constitutes an expression of the protein is possible.
4) All cells in genetically engineered fish show GFP protein expression, as the gene inserted in freshly fertilised egg cell. The fertilised egg divides to give the whole body of fish. So the gene of interest will also present in all cells of the fish.
5) Gene expression analysis for GFP protein may be used to confirm the presence of GFP protein in modified fish. As GFP protein provide visual evidence by expressing the green coloured fluorescence the genetically modified fish can be identified.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.