Final answer:
The lengths of peptides that can bind to MHC class I molecules vary, but they are commonly 8-10 amino acids in length, forming a complex with CD8+ T cells for immune response initiation.
Step-by-step explanation:
The peptide lengths that can bind to MHC class I molecules are typically 8-10 amino acids long. MHC class I molecules present these peptides on the surface of all nucleated cells, signaling to the immune system about the cell's status – whether it is a healthy cell or affected by infection or cancer. The binding groove of MHC class I is formed by the α1 and α2 domains, which create a specific template that accommodates these peptides and presents them to T cells, specifically CD8+ T cells. The recognition of peptide-MHC complexes by T cells is a crucial step in initiating an immune response to pathogens or abnormal cells.