Question 1

Which of the following best describes the Major Histocompatibility Complex (MHC) genetic locus?

Accepted Answer

A region on chromosome 6 that encodes proteins essential for antigen presentation.

Question 2

What is an MHC allele?

Accepted Answer

A variant form of an MHC gene found at a specific locus.

Question 3

Which statement best defines MHC haplotype?

Accepted Answer

The set of MHC alleles inherited together from one parent.

Question 4

What is the main difference between the antigens recognized by CD8+ cytotoxic T cells and CD4+ helper T cells?

Accepted Answer

CD8+ T cells recognize antigens presented by MHC class I, while CD4+ T cells recognize antigens presented by MHC class II.

Question 5

Which structure is recognized by CD8+ cytotoxic T cells?

Accepted Answer

Peptide antigens bound to MHC class I molecules.

Question 6

What is meant by MHC polymorphism?

Accepted Answer

The existence of multiple alleles of MHC genes within a population.

Question 7

Which of the following best explains the difference in peptide binding between MHC class I and class II molecules?

Accepted Answer

MHC class I binds shorter peptides (8-10 amino acids), while MHC class II binds longer peptides (13-18 amino acids).

Question 8

How do the structural differences between MHC class I and class II molecules affect their function?

Accepted Answer

MHC class I has a closed peptide-binding groove, restricting peptide length, while MHC class II has an open groove, allowing longer peptides.

Question 9

Which process is described by the equation $$ 	ext{Antigen} + 	ext{MHC molecule} ightarrow 	ext{Antigen-MHC complex} $$?

Accepted Answer

Antigen presentation

Question 10

What is the role of invariant chain in MHC class II antigen presentation?

Accepted Answer

It blocks the peptide-binding groove to prevent premature peptide loading.

Question 11

Which of the following best describes cross-presentation?

Accepted Answer

The process by which exogenous antigens are presented on MHC class I molecules.

Question 12

Which of the following is a similarity between tapasin and HLA-DM?

Accepted Answer

Both facilitate the loading of high-affinity peptides onto MHC molecules.

Question 13

Which step is disrupted by Human Cytomegalovirus to evade immune detection via the MHC class I pathway?

Accepted Answer

Inhibition of peptide transport into the endoplasmic reticulum.

Question 14

Which equation best represents the process of antigen uptake by antigen-presenting cells?

Accepted Answer

$$ 	ext{Antigen}_{	ext{extracellular}} \xrightarrow{	ext{endocytosis}} 	ext{Antigen}_{	ext{intracellular}} $$

Question 15

Which of the following best explains the role of proteasomes in antigen processing for MHC class I presentation?

Accepted Answer

Proteasomes degrade cytosolic proteins into peptides suitable for MHC class I binding.

Question 16

Which of the following is a consequence of MHC polymorphism in a population?

Accepted Answer

Increased ability to present a diverse array of antigens.

Question 17

Which cell type is primarily responsible for cross-presentation of antigens?

Accepted Answer

Dendritic cells

Question 18

Which equation represents the binding of a peptide to MHC class I in the endoplasmic reticulum?

Accepted Answer

$$ 	ext{Peptide}_{	ext{ER}} + 	ext{MHC I}_{	ext{ER}} ightarrow 	ext{Peptide-MHC I}_{	ext{ER}} $$

Question 19

Which of the following best describes the journey of an antigenic peptide from the cytosol to the cell surface via MHC class I?

Accepted Answer

Proteasomal degradation → Transport into ER → Loading onto MHC I → Transport to cell surface

Antigen Processing and Presentation: Study Notes for Microbiology

Study Guide - Practice Questions