Question

hi I need help with these questions please

Shown below is a map of the OTC-A plasmid which you purified last week from Ecolicells. The positions of the recognition sites for a number of restriction endonucleases are shown (in units of base pairs, 'bp') as are the positions of the genes encoding the proteins that confer resistance to the antibiotics ampicillin and hygromycin. The site initiating replication and the region of the DNA encoding the OTC-A protein are also indicated. Nhel Kpni 1569 1601 Kpl 1030 2295 988 Noti 2310 Sphi 2559 Ndet POTC-A 6401 bp Hygro Amp 1 ZpUC Ori COR 52604 587 Amp: Ampicillin resistance 5405-6265 Hygro: Hygromycin resistance 2933 - 3943

q1 How long is the DNA sequence encoding the protein that confers ampicillin resistance (in bp units)? Input one number only, with no spaces or units. (1 mark)

q2 How long is the DNA sequence encoding the protein that confers hygromycin resistance (in bp units)? Input one number only, with no spaces or units. (1 mark)

q3 What is the size of the OTC-Δ DNA sequence that has been inserted into the pOTC-Δ plasmid (in bp units)? Input one number only, with no spaces or units. (1 mark)

q4 based on the result of question 3  approximately how many amino acid residues long would you expect the OTC-Δ protein to be? You must show your working as well as the final answer to obtain the marks. (1 mark)

Answer 1

Answers:

Q1). How long is the DNA sequence encoding the protein that confers ampicillin resistance (in bp units) ?

Ampicillin resistance gene locates between 5405 - 6265. The length of the DNA sequence would be (6265-5405)+1. So it is 861 base pairs in length.

Answer is 861

Q2). How long is the DNA sequence encoding the protein that confers hygromycin resistance (in bp units)?

Hygromycin resistance gene is located between 2933 - 3943. The length of the DNA sequence would be (3943-2933)+1. So it is 1011 base pairs in length.

Answer is 1011.

Q3). What is the size of the OTC-Δ DNA sequence that has been inserted into the pOTC-Δ plasmid (in bp units)?

OTC-Δ DNA is located between 1030 - 2295. The length of the DNA sequence would be (2295-1030)+1. So it is 1266 base pairs in length.

Answer is 1266.

Q4). Based on the result of question 3  approximately how many amino acid residues long would you expect the OTC-Δ protein to be?

Length of the DNA sequence of OTC-Δ protein is 1266 base pairs. But this includes stop codon as well. Since stop codon does not translates into an aminoacid, 1263 base pairs of DNA only codes for protein.

Each aminoacid is coded by 3 nucleotides. Hence 1263 nucleotides codes for 1263/3 amino acids.

Hence the length of the protein OTC-Δ is 421 aminoacids.