How many peptide linkages are there in a nano peptide?
Answer & explanation
Correct answer: option 2
The correct answer is option 2. 8.
A nanopeptide is a short peptide consisting of between 10 and 100 amino acids.
A peptide linkage, also known as a peptide bond, is the covalent bond formed between the carboxyl group \((-COOH)\) of one amino acid and the amino group \((-NH_2)\) of another amino acid.
Each peptide bond connects one amino acid to the next along the peptide chain.
Calculating Peptide Linkages in a Nanopeptide:
In a nanopeptide with 9 amino acids:
The first amino acid has a free amino group \((-NH_2)\).
The last amino acid has a free carboxyl group \((-COOH)\).
Between each pair of adjacent amino acids, there is one peptide bond.
Therefore, if a nanopeptide contains 9 amino acids, there will be 8 peptide linkages (peptide bonds):
The first amino acid contributes its carboxyl group to form the first peptide bond.
Each subsequent amino acid contributes its amino group to form a peptide bond with the carboxyl group of the preceding amino acid.
Conclusion:
Based on the definition of a nanopeptide and the structure of peptide bonds, a nanopeptide with 9 amino acids will contain 8 peptide linkages. Each linkage represents the covalent bond between successive amino acids in the peptide chain. Hence, the correct answer remains: 8.