$$\text{Phagocyte} + \text{Pathogen} \rightarrow \text{Phagosome}$$

$$\text{Pluripotent stem cell} \rightarrow \text{Leukocyte}$$

$$\text{Pathogen} + C3b \rightarrow \text{Opsonized pathogen}$$

Question 1

Which of the following best describes the primary function of the innate immune system?

Accepted Answer

To provide immediate, non-specific defense against pathogens

Question 2

Which physical barrier is most effective at preventing pathogen entry into the body?

Accepted Answer

Skin with tightly packed, dead outer layers

Question 3

Pattern Recognition Receptors (PRRs) are essential for the innate immune system. What do they recognize?

Accepted Answer

Pathogen-Associated Molecular Patterns (PAMPs)

Question 4

Which Toll-Like Receptor (TLR) is responsible for recognizing bacterial flagellin?

Accepted Answer

TLR5

Question 5

A patient presents with a bacterial infection. Which innate immune cell is most likely to be recruited in large numbers to the site of infection?

Accepted Answer

Neutrophils

Question 6

Which of the following is NOT a characteristic of the innate immune response?

Accepted Answer

Generation of immunological memory

Question 7

The complement system can be activated by three pathways. Which pathway is triggered by lectin binding to microbial carbohydrates?

Accepted Answer

Lectin pathway

Question 8

Which equation best represents the activation of complement component C3?

Accepted Answer

$$C3 \rightarrow C3a + C3b$$

Question 9

During inflammation, which process is responsible for the extravasation of white blood cells from blood vessels into tissues?

Accepted Answer

Increased vascular permeability

Question 10

Which innate immune cell is a professional antigen-presenting cell that bridges innate and adaptive immunity?

Accepted Answer

Dendritic cell

Question 11

Which of the following is a chemical barrier that contributes to the first line of defense?

Accepted Answer

Sebum

Question 12

Which equation describes the formation of reactive oxygen species during the respiratory burst in phagocytes?

Accepted Answer

$$O_2 + e$$^- \rightarrow $$O_2$$^-$$

Question 13

Which innate immune cell is most involved in allergic reactions and releases histamine during inflammation?

Accepted Answer

Basophil/Mast cell

Question 14

Which of the following is a biological barrier to pathogen entry?

Accepted Answer

Normal flora

Question 15

Which equation represents the process of phagocytosis?

Accepted Answer

$$	ext{Phagocyte} + 	ext{Pathogen} ightarrow 	ext{Phagosome}$$

Question 16

Which of the following is a function of cytokines in the innate immune response?

Accepted Answer

Control immune cell activation

Question 17

Which innate immune cell is most effective at killing virus-infected or cancerous cells?

Accepted Answer

Natural killer cell

Question 18

Which equation best represents the process of hematopoiesis?

Accepted Answer

$$	ext{Pluripotent stem cell} ightarrow 	ext{Leukocyte}$$

Question 19

Which of the following is a key difference between the innate and adaptive immune systems?

Accepted Answer

Adaptive immunity recognizes specific 3-D structures or protein sequences

Question 20

Which equation represents the tagging of pathogens for phagocytosis by complement proteins?

Accepted Answer

$$	ext{Pathogen} + C3b ightarrow 	ext{Opsonized pathogen}$$

Innate Immune System: Structure, Function, and Mechanisms

Study Guide - Practice Questions