Final answer:
The primary structure of proteins is the linear sequence of amino acids connected by peptide bonds from the N-terminus to the C-terminus. This sequence is crucial for the protein's biological function, determined by translating mRNA sequences into amino acids. A pentapeptide has a specific sequence denoted with single-letter or three-letter abbreviations.
Step-by-step explanation:
Understanding the Primary Structure of Proteins
The primary structure of proteins is the specific sequence of amino acids in a polypeptide chain. Each amino acid is connected to the next via a peptide bond, and the sequence is written from the N-terminus (the end with a free amine group) to the C-terminus (the end with a free carboxyl group). The sequence determines the biological function of the protein and is crucial for its physiological activity. For example, a pentapeptide composed of five amino acids could be represented with the single-letter amino acid abbreviations as N-K-N-N-N. However, when naming, the last syllable is changed to 'yl', except for the C-terminus, so it would be written as Nyl-Kyl-Nyl-Nyl-N
Sequence of a Pentapeptide
The sequence of a particular pentapeptide would be determined by translating the corresponding mRNA sequences into amino acids. For instance, the mRNA sequence 5'-UCG-GCA-AAU-UUA-GUU-3' would translate to the peptide Serine-Alanine-Asparagine-Leucine-Valine. It is important to compare such sequences to understand how different peptides and subsequent protein functions can arise from even a single change in the mRNA sequence.