The Complement System Flashcards
What is the primary function of the complement system?
To enhance the ability of antibodies and phagocytic cells to clear pathogens.
True or False: The complement system is part of the adaptive immune response.
False
What are the two main pathways that activate the complement system?
Classical pathway and alternative pathway.
Fill in the blank: The complement component C3 is crucial for the ________ of the complement system.
activation
What triggers the classical pathway of complement activation?
The binding of antibodies to antigens.
Which complement component is cleaved into C3a and C3b during activation?
C3
Multiple choice: Which of the following is NOT a function of C3b?
Inhibiting phagocytosis
What is the role of C3a in the complement system?
To act as an anaphylatoxin, promoting inflammation.
True or False: The alternative pathway is antibody-dependent.
False
What is the initial step in the alternative pathway of complement activation?
Spontaneous hydrolysis of C3.
Fill in the blank: The alternative pathway is continuously ________ at low levels.
activated
Which component stabilizes the C3 convertase in the alternative pathway?
Properdin
What is the end result of both the classical and alternative pathways?
Formation of the C3 convertase.
Multiple choice: Which of the following complement proteins is involved in opsonization?
C3b
True or False: The complement system can lyse pathogens directly.
True
What is the common pathway that follows both the classical and alternative pathways?
The terminal pathway leading to the formation of the membrane attack complex (MAC).
Which complement proteins form the membrane attack complex (MAC)?
C5b, C6, C7, C8, and C9.
Fill in the blank: The complement system helps in the clearance of ________ from the body.
immune complexes
What is the function of complement regulatory proteins?
To prevent damage to host cells by regulating complement activation.
Multiple choice: Which complement component is primarily involved in inflammation?
C3a
True or False: The classical pathway can only be activated by IgM antibodies.
False
What is the role of C5 convertase in the complement system?
To cleave C5 into C5a and C5b.
Fill in the blank: The complement system is a part of the ________ immune system.
innate
Which complement pathway is activated by pathogens without the need for antibodies?
Alternative pathway.
What is the significance of the complement system in the immune response?
It enhances opsonization, inflammation, and pathogen lysis.
What is opsonization?
Opsonization is the process by which pathogens are marked for ingestion and destruction by phagocytes.
True or False: Opsonization enhances the ability of the immune system to identify and eliminate pathogens.
True
Fill in the blank: Opsonization involves the binding of ________ proteins to the surface of pathogens.
opsonin
Which of the following is an example of an opsonin? A) Antibodies B) Hormones C) Enzymes
A) Antibodies
What role do phagocytes play in opsonization?
Phagocytes recognize and engulf opsonized pathogens, leading to their destruction.
