Final answer:
Long chains of amino acids, referred to as proteins or polypeptides, are critical components of cellular function, defined by their specific amino acid sequences and linked together by peptide bonds. Proteins, composed of 50 or more amino acids, have structures influenced by the sequence that determine their folding and functional properties.
Step-by-step explanation:
Long chains of amino acids are found in proteins or polypeptides, which are essential biological molecules that perform a variety of functions in living organisms. The sequence of amino acids in a protein is critical for its function, and the sequence is conventionally written from the N-terminal to the C-terminal end, meaning from the free amine group to the free carboxyl group. These amino acids are linked together through peptide bonds to form long chains. If the chain has about 50 amino acids or more, it is generally referred to as a protein or polypeptide, which can be physiologically active and perform specific functions within the cell. Proteins are composed of one or more polypeptide chains, each with its amino acid sequence determining its structure and function.
For instance, a chain consisting of just two amino acid units is termed a dipeptide, and one with three is called a tripeptide. A specific example of an amino acid sequence might be Gly-Trp-Ala, which is different from Ala-Trp-Gly due to the placement of the free amine and carboxyl groups on the respective amino acids. This demonstrates the importance of the specific amino acid sequence in determining the properties and function of the resultant protein.
Additionally, the structure of amino acids allows for the formation of secondary structures like 3-pleated sheets, where the amino acids commonly have short side chains to minimize sterical strain, thus influencing the overall folding and stability of the protein.