1) For the DNA sequence given below, write the complementary DNA sequence that w

ID: 214358 • Letter: 1

Question

1) For the DNA sequence given below, write the complementary DNA sequence that would complete the double-strand.

DNA 3’—A T T G C T T A C T T G C A T -- 5’

DNA 5’—T A A C G A A T G A A C G T A

2) Does it matter which strand is the ‘code strand’? The following two sequences look identical, except one runs 3’-5’ and the other 5’-3’. For each DNA sequence given below, write the mRNA sequence that would be coded from it. Make sure you indicate the direction of each mRNA strand (i.e. 3’ and 5’ ends). Use the Universal triplet code to determine the sequence of amino acids that would be generated for each of the mRNA sequences that you generated in question 2. Remember that the reading of mRNA goes in the 5’-3’ direction (see lab notes for examples).

DNA 3’- T A C C T A C T T T G C C C G A T C C A T– 5’

mRNA 5’--- AUG GAU GAA ACG GGC UAG GUA

amino acid Start-Aspartic Acid-Glutamid Acid-Threonine-Glycine-Stop

DNA 5’- T A C C T A C T T T G C C C G A T C C A T – 3’

mRNA 5’---

amino acid

c. Are the amino acid sequences the same? YES____ NO____

3) What 3’ to 5’ DNA sequence would correspond to a 5’-AUG-3’ start codon?

RNA 5’— A U G—3’

DNA 3’--_T A C__--5’

4) Read the DNA sequence given below in the 3’ to 5’ direction and circle all of the potential start codons (i.e. every time you see the DNA version of a start codon, even if it does not immediately come after a promoter).

How many potential start codons did you find? _______________

Line

3’- T T C C G T A A C T T C G G C G C A T C T A G C T T G A G C T C C A A T C A G G

A C T A C T T A T A A A A A T C T T C T C G A G A G A G C T T T A C T C C T A C T C

T C T T A G T C G A T T C C A T C G G A C C T A C G A T T G A C A A G C G C G G T C

T A C T A T C T A C T T A T T T A T T T A C G A G C G T T G A T T C T A C C T A C T G

A C G A C T A G G G C A T T C T A T A G G A T T A A C T C C T T A T T T T A A C T A

A C T T C C T G G G A A G G C G C C T T T A T C T G A T C C G T A A T C C G T C C G

A A G G C T C T G A T C G G A T T A C T G G G T C A C T G G A A A G T G A C C G C T

G T C T A T T A C T G T A T T T C A T C T G A T T G A C T A T T T T A T A G T C G -5’

5) Now find and circle the promoter region 3’-TATAAAA -5’ in the sequence above.

6) Identify the start codon that is immediately downstream (towards the 5’ end, after the promoter) of the promoter. Indicate the codons that follow the start, and continue until you reach a stop codon.

7) Copy the entire coding sequence that is found in question 4 (from, and including the start codon to the stop codon). Hint: there are 18 codons, each with 3 base pairs, and the coding region is between lines 2 and 4.

DNA: 3’ –

__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __

8) Now write down the mRNA sequence that would be generated from the DNA sequence from question 7. Hint: there are 18 codons, each with 3 base pairs.

mRNA: 5’-

__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __

9) Finally write out the sequence of amino acids that the mRNA sequence in question 8 would code for. Hint: there are 18 amino acids (including the start/methionine). Use the Universal Triplet code from the Gene Expression tutorial document.

Amino acid sequence:

_________--_________--_________--_________--_________--_________--_________--_________--_________--_________--_________--_________--_________--_________--_________--_________--_________--________