# biology aqa alevel proteins question past paper

A scientist used an enzyme to digest a polypeptide containing 101 amino acids.
The digestion produced a range of smaller polypeptides.
The scientist determined the number of amino acids in each of the polypeptides
produced. He also counted the number of polypeptides of each length.
The table below shows some of the scientist’s results.

Number of amino acids in polypeptides | Number of polypeptides of each length
5 | 2
6 |
15 | 3
20 |
Use the information in the table above to calculate the number of
polypeptides:
6 amino acids in length : ?
20 amino acids in length : ?
(edited 4 months ago)
You know the total is 101, the trending amino acids sums to 46, the only way this is achieved is if there is 1 polypeptide of 6 amino acids and 2 of 20 amino acids
Original post by AntonSlayer
You know the total is 101, the trending amino acids sums to 46, the only way this is achieved is if there is 1 polypeptide of 6 amino acids and 2 of 20 amino acids

ok sorry if im slow, but can u tell me why u get 6 and 20 amino acids,if the sum adds up to 101? cus shouldnt u include the 5|2 and and 15|3 row as well?
You can subtract the other, 101-55=46
Original post by AntonSlayer
You can subtract the other, 101-55=46

ohhh thanks so much i get it now