Question

In the end, the complement system destroys invading bacteria by ________.

A) phagocytosis
B) forming a membrane attack complex
C) release of lytic enzymes
D) agglutination
E) neutralization

Answer 1

The complement system destroys invading bacteria by forming a membrane attack complex (MAC) that creates pores in the bacterial membrane leading to cell lysis.

Step-by-step explanation:

In the end, the complement system destroys invading bacteria by forming a membrane attack complex (B). The complement system is an array of about 20 types of soluble proteins that function to identify and destroy extracellular pathogens. It works in conjunction with the antibody response of the adaptive immune system. Complement proteins bind in a highly regulated sequence to microorganisms, particularly those bound by antibodies. After the initial binding, a cascade of sequential binding events follows, leading to the pathogen rapidly becoming coated in complement proteins, which culminates in the formation of the membrane attack complex (MAC), creating destructive pores in the microbial cell membrane, leading to cell lysis.