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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Biology => Topic started by: starburst.95 on June 11, 2011, 12:18:59 pm

Title: STAV 2008 'multiple choice question 5
Post by: starburst.95 on June 11, 2011, 12:18:59 pm
The questions says:
'A section of nucleic acid is taken from a human cell has the following sequence.
                                                      UCUUCAUAA
Its reasonable to conclude from this base sequence that:
(A) each base in this sequence is attached to a deoxyribose sugar
(B) this base seqence codes for 3 different amino acids
(C)this base sequence codes for 9 different amino acids
(D) the complemaentary base sequence would be AGAAGTATT 
my answer was (B) but the solution says (D)?? im confused does anyone know why they chose (D), i thought uracil only in RNA and replaced by thymine in DNA
Title: Re: STAV 2008 'multiple choice question 5
Post by: stonecold on June 11, 2011, 12:29:28 pm
The genetic code is redundant, which means more than one codon can code for the same amino acid, making B incorrect

(D) is correct as the complementary DNA sequence for the RNA sequence presented is the one in the answer.

In transcription, you have base pairing of RNA with the DNA strand, so this is definitely possible.

Edit:  If you look at this codon table, you will see that UCU and UCA both code for the amino acid serine.

http://passel.unl.edu/Image/siteImages/Table1gif.gif

If however they didn't give you this information, it would make the question difficult as it is possible that it could code for three different amino acids.
Title: Re: STAV 2008 'multiple choice question 5
Post by: Charmz on June 11, 2011, 01:08:46 pm
As stonecold said.
And if you used DNA it would be TCTCATAA so the opposite of this is AGAAGTATT.
Title: Re: STAV 2008 'multiple choice question 5
Post by: starburst.95 on June 11, 2011, 02:29:32 pm
 Awsome.Thanks heaps guys :)