Weekly Year 2: Cellular Immunology Exam - May 29, 2026 (Sect

Question 1

In liver cells, bilirubin is mainly conjugated with which of the following?

Accepted Answer

Glucuronic acid — In the liver, bilirubin is primarily conjugated with glucuronic acid to form bilirubin glucuronide, which increases its water solubility and facilitates its excretion.

Question 2

Which of the following pathways are important in red blood cell (RBC) energy metabolism?

Accepted Answer

Glycolysis and pentose phosphate pathway — RBCs rely heavily on anaerobic glycolysis for ATP production. The pentose phosphate pathway is crucial for generating NADPH, which protects RBCs from oxidative damage.

Question 3

An abnormal increase in red blood cell count is characterized by which of the following terms?

Accepted Answer

Polycythemia — Polycythemia refers to an abnormally high concentration of red blood cells in the blood.

Question 4

Which of the following is the brain's preferred source of energy?

Accepted Answer

Glucose — The brain primarily utilizes glucose for energy, even in the fed state. While it can adapt to use ketone bodies during prolonged fasting, glucose remains its preferred and most consistently used fuel.

Question 5

Which of these statements regarding erythrocyte metabolism is TRUE?

Accepted Answer

Erythrocytes lack mitochondria and therefore cannot perform oxidative phosphorylation. — Mature erythrocytes lack mitochondria, precluding oxidative phosphorylation. They rely on anaerobic glycolysis for ATP and the pentose phosphate pathway for NADPH.

Question 6

One of the following statements is TRUE regarding hemolytic disease of the newborn.

Accepted Answer

It is caused by maternal antibodies attacking fetal red blood cells. — Hemolytic disease of the newborn occurs when maternal antibodies cross the placenta and attack fetal red blood cells, usually due to an Rh incompatibility (Rh-negative mother, Rh-positive fetus).

Question 7

Hematocrit is a measure of:

Accepted Answer

The percentage of blood volume occupied by red blood cells — Hematocrit (Hct) is defined as the packed cell volume, representing the percentage of red blood cells in relation to the total blood volume.

Question 8

High-energy phosphate bonds for instant human muscle contraction are readily provided by:

Accepted Answer

Creatine phosphate — Creatine phosphate is a high-energy phosphate compound that can rapidly donate its phosphate group to ADP to regenerate ATP, providing immediate energy for muscle contraction.

Question 9

The Rapoport-Luebering cycle is mainly located in:

Accepted Answer

Erythrocytes — The Rapoport-Luebering shunt is a bypass of glycolysis found in erythrocytes that allows for the production of 2,3-bisphosphoglycerate (2,3-BPG), which regulates hemoglobin's oxygen affinity.

Question 10

The major site of erythrocyte production in humans is the:

Accepted Answer

Bone marrow — In adults, hematopoiesis, including erythropoiesis (red blood cell production), predominantly occurs in the red bone marrow.

Question 11

The most rapid method to resynthesize ATP during exercise is through:

Accepted Answer

The creatine kinase system (creatine phosphate) — The creatine kinase system, using creatine phosphate, provides the quickest burst of ATP regeneration for maximal muscle effort, lasting for a few seconds.

Question 12

Which of the following is FALSE of cardiac and skeletal muscles?

Accepted Answer

Both are under voluntary control. — Skeletal muscle is under voluntary control, while cardiac muscle is involuntary. Both are striated and rely heavily on aerobic respiration, and both possess T-tubules.

Question 13

Which of the following uses ultraviolet (UV) light for examining specimens?

Accepted Answer

Fluorescence microscopy — Fluorescence microscopy utilizes UV or visible light to excite fluorophores in a specimen, causing them to emit light at longer wavelengths that can be observed.

Question 14

Which of the following would be used as preliminary screening for the presence of antibodies to HIV proteins in a patient's blood sample?

Accepted Answer

Enzyme-linked immunosorbent assay (ELISA) — ELISA is a common and cost-effective screening test for detecting antibodies to specific antigens, such as those of HIV. A positive ELISA is typically confirmed with a Western blot.

Question 15

What color light is emitted when antigens are exposed to UV light after being treated with fluorescein isothiocyanate (FITC)?

Accepted Answer

Green — FITC is a common fluorophore that absorbs light in the blue-violet range and emits bright green fluorescence.

Question 16

Which of the following uses the enzyme horseradish peroxidase (HRP)?

Accepted Answer

Immunohistochemistry (IHC) with chromogenic detection — HRP is frequently used as an enzyme conjugate in IHC and ELISA. When a substrate is added, HRP catalyzes a reaction that produces a colored precipitate, allowing visualization of antigen-antibody binding.

Question 17

Which of the following is used extensively to detect antigens in cells or tissue sections, as well as to screen for auto-antibodies to cell or tissue antigens?

Accepted Answer

Immunohistochemistry (IHC) — IHC is a technique that uses antibodies to detect specific antigens in tissue samples. It is also used in indirect formats to detect auto-antibodies in patient sera by identifying which tissue antigens they bind to.

Question 18

Which of the following uses protein antigens separated by molecular weight using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE)?

Accepted Answer

Western blot — A Western blot involves separating proteins by SDS-PAGE, transferring them to a membrane, and then detecting specific proteins using antibodies.

Question 19

Each polypeptide chain (heavy and light) on an immunoglobulin has a variable (V) and constant (C) region. The variable region is responsible for:

Accepted Answer

Antigen binding — The variable regions of the heavy and light chains form the antigen-binding site of an antibody, determining its specificity for a particular antigen.

Question 20

In somatic recombination, the V gene segment rearranges first. The variable region of the antibody molecule is generated via somatic recombination and contains both a constant region and a variable region.

Accepted Answer

D, V — In V(D)J recombination, the V gene segment rearranges first (often to a D segment, then to a J segment, and finally to a C segment). The variable region of the antibody molecule is primarily generated through the combination of V, D, and J gene segments, contributing to antigen binding, and includes a constant region as well.

Question 21

The two types of light chains are:

Accepted Answer

Kappa and Lambda — Immunoglobulins can have either kappa (κ) or lambda (λ) light chains, but not both within the same antibody molecule.

Question 22

Which of the following is NOT true regarding the mechanisms of generating antibody diversity?

Accepted Answer

Junctional diversity is achieved through the random addition of nucleotides by terminal deoxynucleotidyl transferase (TdT). — Allelic exclusion ensures that a B cell expresses only one allele of the heavy chain and one allele of the light chain, but it doesn't restrict the expression of multiple types of heavy or light chains simultaneously. The other mechanisms are key to antibody diversity.

Question 23

IgM is frequently found on the surface of B cells co-expressed with IgD. These two classes are co-expressed not by class switching but by alternative processing of a primary RNA transcript. Both molecules expressed on the single mature B cell have the same binding specificity for antigen.

Accepted Answer

IgM, IgD — Newly formed B cells express both IgM and IgD on their surface. This co-expression is achieved through alternative splicing of the same primary RNA transcript, not class switching. Importantly, these surface immunoglobulins share the same antigen specificity.

Question 24

If alternative processing uses the first polyadenylation site, then what type of heavy chain mRNA is derived?

Accepted Answer

Membrane-bound IgM — Alternative polyadenylation and splicing of the primary mRNA transcript determine whether the resulting immunoglobulin is membrane-bound or secreted, and its isotype. In the context of IgM, using the first polyadenylation site typically leads to the production of membrane-bound IgM.

Question 25

Which of the following diseases affect neutrophils?

Accepted Answer

DiGeorge's syndrome — Chronic granulomatous disease (CGD) is a genetic disorder that affects the function of phagocytes, particularly neutrophils, impairing their ability to kill ingested microorganisms due to defects in the NADPH oxidase system.

Question 26

Phagocytic white cells (leukocytes, e.g. macrophages) congregate within when foreign organisms get through a cut in the skin.

Accepted Answer

Inflammatory exudate — During an inflammatory response to infection or injury, phagocytic cells migrate to the site of damage and congregate within the inflammatory exudate to engulf and eliminate pathogens and cellular debris.

Question 27

Which of the following mediates an early response to viral infections by the innate immune system?

Accepted Answer

Interferons — Interferons are cytokines produced by virus-infected cells that play a crucial role in the early innate immune response to viral infections by inducing an antiviral state in neighboring cells and activating immune cells.

Question 28

Which of the following is a messenger that mediates the connection between the innate and adaptive immune systems?

Accepted Answer

Cytokines — Cytokines are signaling molecules produced by cells of the innate immune system that are essential for initiating and modulating the adaptive immune response. They help in activating, differentiating, and directing adaptive immune cells.

Question 29

Which of the following immune system components would NOT recognize a macromolecule epitope (binding site)?

Accepted Answer

Toll-like receptors (TLRs) — Toll-like receptors (TLRs) are pattern recognition receptors (PRRs) of the innate immune system that recognize conserved molecular patterns (PAMPs) on microbes, not specific epitopes on macromolecules. Antibodies, TCRs, and BCRs are part of the adaptive immune system and recognize specific epitopes.

Question 30

Which of the following is a large genomic region or gene family found in most vertebrates, playing an important role in immunity?

Accepted Answer

Major Histocompatibility Complex (MHC) — The Major Histocompatibility Complex (MHC) is a cluster of genes that encode cell surface proteins essential for adaptive immunity, particularly in the presentation of antigens to T cells. It is found in most vertebrates and plays a critical role in immune recognition.

Question 31

T cells are made in the and complete their differentiation in the .

Accepted Answer

Bone marrow, Thymus — T lymphocytes (T cells) originate from hematopoietic stem cells in the bone marrow but migrate to the thymus for maturation and positive/negative selection.

Question 32

Which of the following is a transmembrane glycoprotein that serves as a co-receptor for the T cell receptor (TCR), and is also known as a cytotoxic T cell (CTL)?

Accepted Answer

CD8 — CD8 is a co-receptor expressed on cytotoxic T lymphocytes (CTLs) and some helper T cells. It binds to MHC Class I molecules on target cells and stabilizes the interaction with the TCR, facilitating T cell activation and cytotoxic activity.

Question 33

Which of the following produce large amounts of antibodies (Igs) and differentiate upon stimulation from CD4+ cells?

Accepted Answer

Plasma cells — Plasma cells are terminally differentiated B cells that are specialized for the secretion of large quantities of antibodies. Their differentiation and antibody production are often heavily influenced by help from CD4+ T helper cells.

Question 34

Which of the following is a glycoprotein expressed on the surface of T helper cells, regulatory T cells, monocytes, macrophages, and dendritic cells?

Accepted Answer

CD4 — CD4 is a surface glycoprotein that serves as a co-receptor for the T cell receptor (TCR) on T helper cells and regulatory T cells. It also binds to MHC Class II molecules. CD4 is also expressed on monocytes, macrophages, and dendritic cells.

Question 35

Which of the following types of antigen presenting cells (APCs) is critical in uptake and presentation of antigen to T cells?

Accepted Answer

Dendritic cells — Dendritic cells are considered the most potent antigen-presenting cells (APCs) and are critical for initiating adaptive immune responses by effectively capturing, processing, and presenting antigens to T cells in lymphoid organs.

Question 36

Which of the following types of antigen presenting cells (APCs) has immunoglobulin that functions as a receptor, then the antigen is internalized, degraded, and presented to T cells?

Accepted Answer

Follicular dendritic cells — Follicular dendritic cells (FDCs) in lymphoid follicles trap immune complexes (antigen bound to antibodies or complement) via Fc receptors and complement receptors on their surface. This allows for prolonged antigen presentation to B cells, aiding in their activation and maturation.

Question 37

Which of the following types of antigen presenting cells (APCs) is specialized for degradation and presentation of particulate antigens to T cells?

Accepted Answer

Macrophages — Macrophages are professional phagocytes that are highly efficient at engulfing and degrading particulate antigens. They then present processed peptide fragments to T cells, playing a significant role in both innate and adaptive immunity.

Weekly Year 2: Cellular Immunology Exam - May 29, 2026 (Sect

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