Question 1

Which of the following best describes the primary function of phagocytic cells in innate immunity, as illustrated in the first image?

Accepted Answer

They engulf and destroy pathogens through a process involving pseudopodia, vacuole formation, and lysosomal enzymes.

Question 2

In the context of insect antiviral defense (see the second image), what is the role of the enzyme Dicer2?

Accepted Answer

It recognizes double-stranded viral RNA and cleaves it into small fragments.

Question 3

Which of the following is a correct sequence of events during phagocytosis, as depicted in the first image?

Accepted Answer

Pseudopodia surround pathogen → Pathogen is engulfed → Vacuole forms → Vacuole fuses with lysosome → Pathogen destroyed → Debris released by exocytosis

Question 4

Which Toll-like receptor (TLR) is responsible for recognizing bacterial flagellin, as shown in the third image?

Accepted Answer

TLR5

Question 5

What is the main effect of histamine release by mast cells during the inflammatory response (see the fourth image)?

Accepted Answer

It increases the permeability and dilation of nearby capillaries, allowing immune cells and antimicrobial peptides to enter the tissue.

Question 6

Which of the following best explains why the skin is considered a barrier defense in innate immunity?

Accepted Answer

It acts as a physical and chemical barrier, preventing pathogen entry and creating a hostile environment through secretions.

Question 7

A patient with a genetic defect in TLR4 would have difficulty recognizing which type of pathogen-associated molecule?

Accepted Answer

Lipopolysaccharide

Question 8

Which of the following is a likely consequence of a systemic inflammatory response, as described in the study materials?

Accepted Answer

A rapid increase in white blood cell count and possibly fever throughout the body

Question 9

How do interferons contribute to innate immunity in vertebrates?

Accepted Answer

They induce nearby uninfected cells to produce substances that inhibit viral replication.

Question 10

Which of the following best describes the function of the lymphatic system in innate immunity, as shown in the sixth image?

Accepted Answer

It circulates lymph containing immune cells, which filter pathogens and debris in lymph nodes.

Question 11

A bacterium with a thick outer capsule is able to evade which aspect of the innate immune response?

Accepted Answer

Recognition and phagocytosis by immune cells

Question 12

Which of the following is a correct statement about the complement system in innate immunity?

Accepted Answer

It consists of about 30 proteins that circulate in the blood and help destroy pathogens by promoting inflammation and cell lysis.

Question 13

Why do some pathogens, such as Mycobacterium tuberculosis, persist in the body despite being engulfed by phagocytic cells?

Accepted Answer

They resist breakdown and destruction after being engulfed, allowing them to survive and reproduce within host cells.

Question 14

Which of the following best explains the accumulation of pus at an infection site?

Accepted Answer

It is a fluid rich in white blood cells, dead pathogens, and debris from damaged tissue, indicating immune defenses in action.

Question 15

Which of the following is a unique feature of innate immunity in vertebrates compared to invertebrates?

Accepted Answer

Production of interferons and natural killer cells

Question 16

A mutation that prevents the fusion of lysosomes with vacuoles in phagocytic cells would most directly impair which step of the immune response?

Accepted Answer

Destruction of engulfed pathogens by toxic compounds and enzymes

Question 17

Which of the following best describes the role of cytokines in the inflammatory response?

Accepted Answer

They are signaling molecules released by macrophages that recruit neutrophils and promote inflammation.

Question 18

Which of the following is a plausible reason why some insect species can mount an innate immune response to parasitic wasp eggs, while others cannot?

Accepted Answer

Some species lack the recognition proteins needed to detect molecules on the wasp egg surface.

Question 19

Which of the following best explains why fever may be beneficial during a systemic inflammatory response?

Accepted Answer

It may enhance phagocytosis and accelerate tissue repair by speeding up chemical reactions.

Innate Immunity: Recognition and Response in Animals

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