Subject: Biotechnology
Semester: 2nd Semester
Exam Name: FYUG Even Semester Exam, 2024
SECTION-A (Answer any fifteen) 1 × 15 = 15
1. Define immunity.
Immunity is the ability of an organism to resist a particular infection or toxin by the action of specific antibodies or sensitized white blood cells
.2. What is humoral immune response?
The humoral immune response is the aspect of immunity that is mediated by macromolecules—including secreted antibodies, complement proteins, and certain antimicrobial peptides—found in extracellular fluids
.3. Define hematopoiesis.
Hematopoiesis is the process through which all cellular blood components, including immune cells, are produced from hematopoietic stem cells in the bone marrow
.4. What is class switching?
Class switching is a biological process occurring in activated B cells where the antibody produced changes from one class (e.g., IgM) to another (e.g., IgG, IgA, or IgE) while maintaining specificity for the same antigen
.5. What is clonal selection theory?
This theory states that specific antigen receptors exist on lymphocytes before they encounter an antigen; once an antigen binds, that specific cell is "selected" to multiply into a large clone of identical cells
.6. What are idiotypes?
Idiotypes are the unique set of antigenic determinants (epitopes) found in the variable regions (V-regions) of an antibody molecule that distinguish it from other antibodies
.7. What is J-chain?
The J-chain (joining chain) is a small polypeptide expressed by mucosal and glandular plasma cells, required for the polymerization of secretory antibodies like IgM and IgA
.8. Define allergens.
Allergens are typically harmless environmental substances (like pollen or dust) that can trigger an exaggerated immune response or allergic reaction in sensitive individuals
.9. What is antigen presenting cell?
An Antigen Presenting Cell (APC) is a specialized immune cell (like macrophages or dendritic cells) that captures, processes, and displays foreign antigens on its surface via MHC molecules to activate T-cells
.10. Define haplotype.
A haplotype is a group of genes within an organism that was inherited together from a single parent; in immunology, it often refers to the specific set of MHC alleles on a single chromosome
.11. What do you mean by endogenous antigens?
Endogenous antigens are antigens produced within a normal cell as a result of normal cell metabolism or because of viral or intracellular bacterial infection
.13. Define autoimmune disease.
An autoimmune disease is a condition in which the immune system mistakenly attacks and destroys healthy body tissue because it fails to distinguish "self" from "non-self"
.15. What is inflammation?
Inflammation is a localized physical condition in which part of the body becomes reddened, swollen, hot, and often painful, especially as a reaction to injury or infection
.16. What is the full form of AIDS?
Acquired Immunodeficiency Syndrome
19. Define vaccination.
Vaccination is the administration of a vaccine to help the immune system develop protection from a disease by stimulating the production of antibodies and memory cells
.SECTION-B (Answer any five) 2 × 5 = 10
21. Write a note on adaptive immunity. [2]
Adaptive immunity (or acquired immunity) is highly specific and provides long-lasting protection
. It involves B-lymphocytes and T-lymphocytes, characterized by its ability to recognize specific antigens and create immunologic memory for faster responses upon re-exposure.22. Write about T-lymphocytes and B-lymphocytes. [2]
24. What are the properties of an antigen? [2]
Antigens must possess foreignness (recognized as non-self), high molecular weight, chemical complexity, and immunogenicity (the ability to induce an immune response)
.29. Differentiate between active immunity and passive immunity. [2]
30. Write a note on immuno-electrophoresis. [2]
Immuno-electrophoresis is a laboratory technique used to separate and identify proteins based on their electrophoretic mobility and their reaction with specific antibodies, forming visible precipitin lines
.SECTION-C (Answer any five) 5 × 5 = 25
31. Note on different types of immunoglobulins. Structure of IgG. [2+3=5]
There are five types of immunoglobulins: IgG, IgM, IgA, IgD, and IgE
.Structure of IgG: It is a Y-shaped monomeric molecule consisting of two identical heavy (H) chains and two identical light (L) chains joined by disulfide bonds
. It has a constant region (Fc) and two antigen-binding sites (Fab).35. Structure and antigen processing of MHC-class I molecule. [2+3=5]
Structure: MHC-class I consists of a large alpha (α) chain with three domains (α1, α2, α3) non-covalently associated with a smaller β2-microglobulin molecule
.Antigen Processing: MHC-I processes endogenous antigens
. Proteins in the cytosol are degraded by proteasomes into peptides, transported to the ER via TAP, and loaded onto MHC-I molecules for display to CD8+ T-cells.36. Structure and antigen processing of MHC-class II molecule. [2+3=5]
Structure: MHC-class II is a heterodimer composed of two non-covalently associated glycoproteins: an alpha (α) chain and a beta (β) chain, both of which span the cell membrane
.Antigen Processing: MHC-II processes exogenous antigens
. Extracellular antigens are internalized via endocytosis, degraded into peptides in endosomes, and loaded onto MHC-II molecules after the invariant chain is removed, then displayed to CD4+ T-cells.39. Define vaccine and its types. [1+4=5]
A vaccine is a biological preparation that provides active acquired immunity to a particular infectious disease
.Types of Vaccines:
- Live-attenuated vaccines: Use a weakened form of the germ.
- Inactivated vaccines: Use a killed version of the germ.
- Subunit/Recombinant/Conjugate: Use specific pieces of the germ.
- Toxoid vaccines: Use a toxin made by the germ.
40. Define ELISA. Principle and applications. [1+2+2=5]
ELISA (Enzyme-Linked Immunosorbent Assay) is a plate-based assay technique designed for detecting and quantifying substances such as peptides, proteins, antibodies, and hormones
.Principle: It relies on the specific binding of antibodies to antigens and the use of an enzyme-labeled antibody to produce a color change that can be measured
.Applications: Used in clinical diagnosis (e.g., HIV testing), food industry (allergen detection), and environmental monitoring
.Exam Focus Enhancements
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