Hi
Why do we need to do 1/3 - 1?
930 - 6 nucleotides for the stop and start codon = 924
924/3 = 308 with no remainder, so it should make exactly 1/3 amino acids
What is wrong with my reasoning?
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Wait whats the actual answer given? 307? Im just as confused?
930 isn’t the number of nucleotides in the coding sequence actually. U have to remove two non coding regions and we will get coding sequence but still don’t know the exact nucleotides. Once we got the coding sequence, we will have to remove the STOP codon but don’t need to remove start codon so I guess that’s why the answer is 1/3 - 1.
I also got wrong that one too.
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How come we dont need to remove the start codon?
I guess it’s because the given options only have the total numbers of amino acids obtained, since start codon still codes for the amino acid, although it has to be removed to form a specific protein, while the stop codon doesn’t code any amino acid. I guess that’s the reason.
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wait so is the answer ( 930 - 3 (stop) ) / 3 = 309 or ( 930 / 3 ) - 1 = 310 ??
because the start codon codes for methionine. it is a coding sequence unlike stop codon
that gives the same answer! they are both equal to 309
oh rightttt I forgot to subtract the 1
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the start codon codes for methionine so it is not considered a non coding sequence. in this case only the stop codon should be taken out to find the coding sequence
using 930/3 will give us the total codon number and minus 1 will take out the non coding part which is the stop codon.
using 930-3 for the nucleotide sequence then dividing it by 3 will also give the same solution
hope this helps!