Final answer:
The 'membrane attack complex (MAC)' formed by multiple C9 molecules creates a pore in pathogens. A C5 fragment initiates the assembly with C6, C7, C8, and C9, disrupting the pathogen's plasma membrane and leading to cell lysis.
Step-by-step explanation:
The formation of transmembrane pores in the pathogen's surface is a biological process that is related to the immune system's complement pathway.
Multiple molecules of the complement protein C9 polymerize to form the so-called membrane attack complex (MAC). This complex inserts into the plasma membrane of pathogens, such as bacteria, and forms a pore that disrupts homeostasis.
The exact number of C9 molecules required for pore formation can vary, but typically, many C9 molecules come together in this process.
In both the classical and alternative complement pathways, the complement components C5, C6, C7, C8, and C9 interact.
A fragment from C5 joins C6, C7, C8, and C9 to form the MAC. Once formed, the MAC creates a hole in the plasma membrane of the invading pathogen, leading to the influx of water into the hyperosmotic cytoplasm, which eventually causes the pathogen to swell and burst (lyse), effectively killing it.