Question

directions: create a polypeptide chain with the following 3 amino acids (r groups) in the table below. remember that a peptide bond exists between each of the amino acids. specifically the peptide bond lies between the amino group of one amino acid and the carboxyl group of the other amino acid. review the structure on the previous page and or review the examples in your textbook on pp. 55 - 56. remember: the amino group and carboxyl group are the same and are present in each amino acid the peptide bond is the same in each bond between amino acids the only component or group that is different are the “r” groups which represent your amino acids below. amino acids for polypeptide chain these are your
\ groups amino acid bonds alanine ch₃ valine ch ch₃ ch₃ glycine h my polypeptide/protein chain: biology a cp - hs4036 - unit 1 © skyrocket, inc. student activity workbook - 4/2021 15

Explanation:

Step1: Recall peptide - bond formation

A peptide bond forms between the amino group ($-NH_2$) of one amino - acid and the carboxyl group ($-COOH$) of another amino - acid, with the loss of a water molecule ($H_2O$).

Step2: Write the general structure of an amino - acid

An amino - acid has the general structure $NH_2 - CH(R)-COOH$, where $R$ is the side - chain. For alanine, $R = CH_3$; for valine, $R=(CH_3)_2CH$; for glycine, $R = H$.

Step3: Form the polypeptide chain

The polypeptide chain will be formed by linking the amino acids through peptide bonds. The structure of the polypeptide chain (from amino - terminus to carboxyl - terminus) will be $NH_2 - CH(CH_3)-CO - NH - CH((CH_3)_2CH)-CO - NH - CH(H)-COOH$.

Answer:

$NH_2 - CH(CH_3)-CO - NH - CH((CH_3)_2CH)-CO - NH - CH(H)-COOH$