Weekly Year 2: Cellular Immunology Exam - June 12, 2026 (...

Question 1

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

Accepted Answer

Glucuronic acid — In hepatocytes, bilirubin is primarily conjugated with glucuronic acid to form bilirubin diglucuronide, increasing its water solubility for excretion in bile.

Question 2

Which of the following pathways are important in Red Blood Cell (RBC) energy metabolism?

Accepted Answer

Glycolysis and Pentose Phosphate Pathway — RBCs lack mitochondria, so their primary energy source is glycolysis. The Pentose Phosphate Pathway is also crucial for producing NADPH, which protects against 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 relies almost exclusively on glucose for energy under normal physiological conditions. While it can utilize ketone bodies during prolonged fasting, glucose is its primary and preferred substrate.

Question 5

Which of these statements is TRUE regarding cellular energy metabolism?

Accepted Answer

Oxidative phosphorylation is the most efficient ATP-generating pathway. — Oxidative phosphorylation, occurring in the mitochondria, yields the largest amount of ATP from a single glucose molecule. Anaerobic glycolysis is less efficient, and the Krebs cycle is in the mitochondrial matrix.

Question 6

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

Accepted Answer

It is typically caused by maternal Rh incompatibility and fetal exposure to maternal antibodies. — Hemolytic disease of the newborn (HDN) most commonly occurs when a mother is Rh-negative and her fetus is Rh-positive. Maternal antibodies against fetal red blood cells can cross the placenta and cause hemolysis.

Question 7

Hematocrit is a measure of what?

Accepted Answer

The percentage of blood volume occupied by red blood cells — Hematocrit (Hct) represents the proportion, by volume, of the blood that consists of red blood cells.

Question 8

High-energy phosphate bonds for instant human muscle contraction are readily provided by which molecule?

Accepted Answer

Phosphocreatine — Phosphocreatine acts as a rapid reservoir of high-energy phosphate bonds that can quickly regenerate ATP from ADP during intense muscular activity.

Question 9

The Rapapport-Luebering cycle is mainly located in which of the following?

Accepted Answer

Erythrocytes — The Rapapport-Luebering cycle, which produces 2,3-bisphosphoglycerate (2,3-BPG), is found in mature erythrocytes and plays a role in regulating hemoglobin's oxygen affinity.

Question 10

The major site of erythrocyte production in humans in adulthood is the:

Accepted Answer

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

Question 11

The most rapid method to resynthesize ATP during exercise is through which pathway?

Accepted Answer

Creatine phosphate system — The creatine phosphate system (also known as the phosphagen system) provides the quickest way to regenerate ATP from ADP, essential for very short bursts of intense activity.

Question 12

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

Accepted Answer

Both are under voluntary control. — While both cardiac and skeletal muscles are striated and contain sarcomeres, only skeletal muscle is under voluntary control. Cardiac muscle is involuntary.

Question 13

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

Accepted Answer

Fluorescence microscopy — Fluorescence microscopy utilizes UV or visible light to excite fluorescent molecules (fluorophores) in a specimen, causing them to emit light at longer wavelengths, which is then detected.

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

ELISA (Enzyme-Linked Immunosorbent Assay) — ELISA is a common and cost-effective screening test for detecting antibodies in serum. A positive ELISA result for HIV antibodies is typically confirmed with a more specific test like 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 fluorophore that, when excited by UV light, typically emits light in the green spectrum. This is widely used in immunofluorescence assays.

Question 16

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

Accepted Answer

ELISA (Enzyme-Linked Immunosorbent Assay) — HRP is a common enzyme used as a label in ELISA and Western Blotting. It catalyzes a reaction that produces a detectable color change or light emission.

Question 17

Which of the following techniques 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) — Immunohistochemistry utilizes antibodies conjugated to enzymes or fluorophores to visualize the location and distribution of specific antigens within tissue samples. It's also used to detect auto-antibodies.

Question 18

Which of the following techniques 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. This allows for the identification of proteins based on size and antigenicity.

Question 19

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

Accepted Answer

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

Question 20

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

Accepted Answer

gene segments, variable region — Somatic recombination, specifically V(D)J recombination, involves the rearrangement of gene segments. This process generates the diversity within the variable region of both heavy and light chains, which is crucial for antigen binding.

Question 21

The two types of light chains found in immunoglobulins are:

Accepted Answer

Kappa (κ) and Lambda (λ) — Immunoglobulins have either kappa (κ) or lambda (λ) light chains. A single antibody molecule will have two identical light chains of either kappa or lambda type, but not both.

Question 22

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

Accepted Answer

Junctional diversity (addition or deletion of nucleotides at V-D and D-J junctions) contributes to antigen binding site… — Class switching recombination (CSR) alters the constant region of the antibody, changing its effector function and isotype, but it does not change the variable region, and therefore does not change the antigen specificity.

Question 23

is frequently found on the surface of B cells co-expressed with . 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 — Naive mature B cells express both IgM and IgD on their surface. This co-expression is achieved through alternative splicing of the pre-mRNA, not class switching, and both isotypes on a single B cell recognize the same antigen.

Question 24

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

Accepted Answer

Membrane-bound IgM — The first polyadenylation site downstream of the VDJ exon typically leads to the production of membrane-bound IgM. Subsequent polyadenylation sites lead to secreted forms or other isotypes after class switching.

Question 25

Which of the following diseases primarily affects neutrophils, impairing their ability to kill ingested microorganisms?

Accepted Answer

DiGeorge's syndrome — Chronic granulomatous disease (CGD) is a genetic disorder that affects the function of phagocytes, particularly neutrophils, by impairing their ability to produce reactive oxygen species needed for killing pathogens.

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 inflammation, phagocytic cells migrate to the site of injury or infection, accumulating in 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 a crucial part of the innate immune response to viral infections. They are signaling proteins that inhibit viral replication and alert other 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 soluble signaling molecules produced by cells of the immune system, including innate immune cells. They play a vital role in orchestrating and bridging the innate and adaptive immune responses.

Question 29

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

Accepted Answer

MHC molecules presenting processed peptides — MHC molecules themselves do not directly recognize macromolecule epitopes. Instead, they bind and present processed peptide fragments to T cell receptors.

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 critical region of genes in vertebrates that encodes cell surface proteins essential for adaptive immunity, including antigen presentation to T cells.

Question 31

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

Accepted Answer

Bone marrow, Thymus — Hematopoietic stem cells in the bone marrow give rise to lymphocytes, including T cell precursors. These precursors then migrate to the thymus for maturation and 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 primarily found on cytotoxic T cells (CTLs) and some regulatory T cells. It binds to MHC class I molecules, stabilizing the interaction between the T cell and the antigen-presenting cell.

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 lymphocytes that are specialized for the secretion of large quantities of antibodies. Their differentiation is often T cell-dependent, requiring 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 transmembrane glycoprotein that serves as a co-receptor for the T cell receptor (TCR) and binds to MHC class II molecules. It is primarily expressed on T helper cells, but also on regulatory T cells, 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 crucial for initiating adaptive immune responses by presenting antigens to naive 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

B cells — B cells express B cell receptors (BCRs), which are membrane-bound antibodies. When a B cell binds to an antigen via its BCR, it internalizes, processes, and presents peptides from that antigen on MHC class II molecules to T helper cells.

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 efficiently engulf and degrade particulate antigens. They then present peptide fragments of these antigens on MHC class II molecules to T helper cells, playing a significant role in clearing infections.

Weekly Year 2: Cellular Immunology Exam - June 12, 2026 (...

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