Proteins are biological polymers formed from amino acid monomers. A segment of a specific polypeptide chain is represented below:
-Ala-Asp-Cys-Leu- \text{-Ala-Asp-Cys-Leu-} -Ala-Asp-Cys-Leu-Each amino acid residue in the sequence is represented by its standard three-letter abbreviation.
Identify the level of protein structure represented by this sequence.
Draw the structure of the -Ala-Asp-\text{-Ala-Asp-}-Ala-Asp- section of this polypeptide chain, showing the peptide linkage and the respective R groups. Show open bonds at both ends of the section.
State the type of chemical reaction that occurs when amino acids are joined together during translation to form a polypeptide.
Explain why the interaction between two cysteine R groups in a protein's tertiary structure is significantly stronger than the interaction between a leucine R group and an alanine R group.
Deduce the type of interaction that occurs between a lysine R group and a glutamic acid R group in the tertiary structure of a protein.
30 exam-style questions on AQA A Level Chemistry Amino acids, proteins and DNA (A-level only), covering Amino acids (A-level only), Proteins (A-level only), Enzymes (A-level only), DNA (A-level only), and Action of anticancer drugs (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.