Table of contents

1. Introduction to Microbiology3h 22m
2. Disproving Spontaneous Generation1h 18m
3. Chemical Principles of Microbiology3h 38m
4. Water1h 28m
5. Molecules of Microbiology2h 23m
6. Cell Membrane & Transport3h 28m
7. Prokaryotic Cell Structures & Functions5h 52m
8. Eukaryotic Cell Structures & Functions2h 18m
9. Microscopes2h 46m
10. Dynamics of Microbial Growth4h 36m
11. Controlling Microbial Growth4h 10m
12. Microbial Metabolism5h 16m
13. Photosynthesis2h 31m
14. DNA Replication2h 25m
15. Central Dogma & Gene Regulation7h 14m
16. Microbial Genetics4h 44m
17. Biotechnology3h 0m
18. Viruses, Viroids, & Prions4h 56m
19. Innate Immunity7h 15m
20. Adaptive Immunity7h 14m
21. Principles of Disease6h 57m

21. Principles of Disease

3) Surviving Inside Phagocytic Cells

Microbiology

21. Principles of Disease

3) Surviving Inside Phagocytic Cells

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Multiple Choice

Some encapsulated bacterial pathogens are said to be serum-resistant. Serum resistant pathogens avoid the effects of the complement system proteins. How are encapsulated bacteria able to be serum-resistant and avoid phagocytosis?

The capsule ensures that C3b cannot bind the pathogen and trigger phagocytosis or opsonization.

The capsule ensures that C3 convertase cannot trigger the activation of phagocytic immune cells.

The capsule ensures that the pathogen will be able to escape the phagosome inside the phagocytic cell.

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Verified step by step guidance

Understand the role of the bacterial capsule: The capsule is a polysaccharide layer that surrounds some bacteria, providing a physical barrier against the host's immune system.

Learn about the complement system: The complement system is a part of the immune system that enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells, promoting inflammation and attacking the pathogen's cell membrane.

Explore how the capsule prevents C3b binding: The capsule can prevent the binding of C3b, a key protein in the complement system, to the bacterial surface. This prevents opsonization, which is the process that marks pathogens for phagocytosis.

Examine the role of C3 convertase: C3 convertase is an enzyme complex that plays a crucial role in the activation of the complement system. The capsule can inhibit the formation or function of C3 convertase, thereby preventing the activation of phagocytic immune cells.

Consider the escape from phagocytosis: Some encapsulated bacteria can avoid being engulfed by phagocytes or can escape from the phagosome, a vesicle formed around a pathogen by the phagocyte, thus avoiding destruction by the host's immune system.