Question 1

Which of the following best describes the difference between innate and adaptive immunity?

Accepted Answer

Innate immunity is present at birth, acts rapidly, and is nonspecific, while adaptive immunity is slower, specific to pathogens, and has a memory component.

Question 2

A patient presents with a high white blood cell (WBC) count. Which of the following is the most likely explanation?

Accepted Answer

The patient may have a bacterial infection, autoimmune disease, or side effects from medication.

Question 3

Which physical factor of the skin contributes most to its role as a barrier in innate immunity?

Accepted Answer

Shedding and dryness of the epidermis containing keratin

Question 4

Which chemical factor is responsible for destroying bacterial cell walls in tears, saliva, and urine?

Accepted Answer

Lysozyme

Question 5

What is the primary function of neutrophils in the immune system?

Accepted Answer

Phagocytize bacteria and fungi during early stages of infection

Question 6

Which process describes the movement of phagocytes from the bloodstream to the site of tissue damage during inflammation?

Accepted Answer

Diapedesis

Question 7

A patient with a deficiency in C3 complement protein is most likely to experience which of the following?

Accepted Answer

Susceptibility to bacterial infections due to impaired cytolysis, opsonization, and inflammation

Question 8

Which of the following is a function of the ciliary escalator in the respiratory tract?

Accepted Answer

Traps microbes in mucus and transports them away from the lungs

Question 9

Which equation best represents the splitting of complement protein C3 during complement activation?

Accepted Answer

$$C3 \rightarrow C3a + C3b$$

Question 10

Which of the following best describes microbial antagonism?

Accepted Answer

Normal microbiota produce substances harmful to pathogens and compete for space and nutrients.

Question 11

Which of the following is NOT a function of inflammation?

Accepted Answer

Producing antibodies against pathogens

Question 12

Which of the following is a correct statement about Toll-like receptors (TLRs)?

Accepted Answer

TLRs on host cells recognize pathogen-associated molecular patterns (PAMPs) and induce cytokine release.

Question 13

Which of the following is a chemical factor that inhibits microbial growth on the skin?

Accepted Answer

Sebum, which forms a protective film and lowers skin pH

Question 14

Which of the following is a consequence of complement activation?

Accepted Answer

Formation of a membrane attack complex (MAC) leading to cytolysis

Question 15

Which of the following best describes the action of interferons (IFNs) alpha and beta?

Accepted Answer

They cause neighboring cells to produce antiviral proteins that inhibit viral replication.

Question 16

Which iron-binding protein is found in blood and tissue fluids and helps deprive pathogens of iron?

Accepted Answer

Transferrin

Question 17

A patient with sickle cell trait is relatively protected against which pathogen due to genetic resistance?

Accepted Answer

Plasmodium falciparum (malaria)

Question 18

Which of the following is a correct description of opsonization?

Accepted Answer

The coating of a microorganism with serum proteins to enhance phagocytosis

Question 19

Which antimicrobial peptide mechanism is most likely to result in microbial cell lysis?

Accepted Answer

Formation of pores in plasma membranes

Question 20

Which of the following is a real-world example of microbial antagonism in the human body?

Accepted Answer

Lactobacillus in the vagina produces $$H_2O_2$$ under anaerobic conditions, inhibiting Chlamydia.

Innate Immunity: Nonspecific Defenses of the Host

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