Immunotechnology & Physiology

Immunotechnology & Physiology

A G protein-coupled receptor (GPCR) is a cell-surface transmembrane receptor that works with the help of a G-protein. Ch

GPCR activation promotes guanine nucleotide exchange on heterotrimeric G-alpha subunit, replacing GDP with GTP. GTP-bound alpha dissociates to regulate effectors like adenylyl cyclase. Intrinsic GTPase later hydrolyzes GTP to GDP terminating signaling cascade.

Ref: Alberts et al., Molecular Biology of the Cell, 6th Edition, Chapter 15 and Nelson and Cox, Lehninger Principles of Biochemistry, 7th Edition, Chapter 12 discuss GPCR signaling where heterotrimeric G-proteins bind GTP upon activation to modulate downstream effectors, published by Garland and Freeman.

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Immunotechnology & Physiology

NATIVE-PAGE experiment for separation of proteins, if the amount of cross-linker is increased, what would happen?

Increasing bis-acrylamide cross-linker reduces gel pore size and may increase heterogeneity, restricting protein migration and diminishing resolution. Unlike SDS-PAGE, native PAGE retains conformation, so excessive crosslinking impedes separation rather than altering hydration or denaturing proteins.

Ref: Wilson and Walker, Principles and Techniques of Biochemistry and Molecular Biology, 8th Edition, Chapter 8 describes native PAGE where increased cross-linker concentration decreases pore size reducing separation efficiency among proteins, published by Cambridge University Press.

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Immunotechnology & Physiology

Choose the correct range of membrane potential, the voltage across a membrane.

Resting membrane potentials typically range from -20 mV to -200 mV depending on cell type, established by Na+/K+ ATPase and selective permeability to K+. Neurons near -70 mV, plant cells more negative, maintaining electrochemical gradient essential for excitability.

Ref: Alberts et al., Molecular Biology of the Cell, 6th Edition, Chapter 11 and Lodish et al., Molecular Cell Biology, 8th Edition, Chapter 11 explain resting membrane potential range -20 to -200 mV generated by Na+/K+ pump and K+ leak channels, published by Garland Science.

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Immunotechnology & Physiology

HPLC is the diagnostic modality for

High-performance liquid chromatography separates hemoglobin variants based on charge and hydrophobicity, quantifying HbA, HbF, HbS, HbA2. This makes it gold standard for diagnosing sickle cell disease, thalassemia, and other hemoglobinopathies causing hemolytic anemia.

Ref: Hoffbrand et al., Essential Haematology, 7th Edition, Chapter 11 and Dacie and Lewis Practical Haematology, 12th Edition, describe HPLC as diagnostic modality for hemoglobinopathy-associated anemias including thalassemia and sickle cell variants, published by Wiley Blackwell.

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Immunotechnology & Physiology

Which of the following techniques gives the most information about the positional and spatial characteristics of all ato

Nuclear magnetic resonance spectroscopy provides atomic-level positional and spatial information including distances and angles for all atoms in solution. Edman sequencing gives primary structure only, circular dichroism reports secondary structure content, and unfolding assesses stability not atomic coordinates.

Ref: Branden and Tooze, Introduction to Protein Structure, 2nd Edition, Chapter 2 and Nelson and Cox, Lehninger Principles of Biochemistry, 7th Edition, Chapter 4 discuss NMR spectroscopy for atomic resolution structural determination versus Edman and CD methods, published by Garland and Freeman.

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Immunotechnology & Physiology

Which among the following factors has the greatest effect on the ability of blood to transport oxygen?

Oxygen transport depends primarily on hemoglobin concentration because each gram binds 1.34 mL oxygen, far exceeding dissolved oxygen. Temperature, pH, and solubility modestly affect affinity via Bohr effect but do not change carrying capacity like hemoglobin amount.

Ref: Guyton and Hall, Textbook of Medical Physiology, 14th Edition, Chapter 41 explains hemoglobin concentration determines oxygen carrying capacity compared to pH, temperature, and dissolved oxygen effects on hemoglobin-oxygen affinity, published by Elsevier.

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Immunotechnology & Physiology

Trajectory of molecular dynamic simulation of a complex receptor-drug can be analyzed using (A) Root Mean Square Deviati

Molecular dynamics trajectories are evaluated via RMSD measuring overall structural deviation over time, RMSF indicating per-residue flexibility, radius of gyration reflecting compactness changes, and hydrogen bond counts assessing receptor-drug interaction stability throughout simulation.

Ref: Leach, Molecular Modelling: Principles and Applications, 2nd Edition, Chapter 7 and Schlick, Molecular Modeling and Simulation, discuss RMSD, RMSF, radius of gyration, and hydrogen bond analysis for assessing MD trajectory stability, published by Pearson and Springer.

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Immunotechnology & Physiology

Which among the following statements are true? (A) Continuous conduction is faster than saltutatory conduction. (B) The

Neural coding relies on firing frequency and recruitment of sensory neurons for intensity. Larger diameter reduces internal resistance increasing conduction velocity, while myelin and diameter critically determine speed. Saltatory conduction is faster than continuous propagation.

Ref: Bear et al., Neuroscience: Exploring the Brain, 4th Edition, Chapter 4 and Kandel et al., Principles of Neural Science, 6th Edition, Chapter 7 discuss axon diameter, myelination, rate coding, and saltatory versus continuous conduction velocity, published by McGraw-Hill.

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Immunotechnology & Physiology

Which among the followings is true of the sympathetic nervous system?

Sympathetic division of autonomic nervous system uses acetylcholine at preganglionic to postganglionic nicotinic synapse in ganglia, but predominantly norepinephrine at postganglionic neuroeffector junctions, except sweat glands, distinguishing its dual-transmitter organization.

Ref: Guyton and Hall, Textbook of Medical Physiology, 14th Edition, Chapter 60 describes autonomic nervous system organization and Bear et al., Neuroscience, 4th Edition, Chapter 15 details sympathetic neurotransmitters acetylcholine in ganglia and norepinephrine at effectors, published by Elsevier.

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Immunotechnology & Physiology

A swing out rotor exhibits the maximum radius from the axis of the rotor to the bottom of the tube as 7 cm. If the rotor

Relative centrifugal field calculated as RCF equals 1.118 times 10^-5 times radius in centimeters times rpm squared. Using 7 cm and 20000 rpm yields approximately 31304 g, matching 31360 value, demonstrating high-speed pelleting force.

Ref: Wilson and Walker, Principles and Techniques of Biochemistry and Molecular Biology, 8th Edition, Chapter 9 explains centrifugation and RCF formula RCF equals 1.118 x 10^-5 r N^2 for calculating centrifugal force, published by Cambridge University Press.

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Immunotechnology & Physiology

Which among the followings is NOT a termination codon?

Universal genetic code includes three stop codons TAA ochre, TAG amber, and TGA opal terminating translation via release factors. TGG encodes tryptophan, an aromatic amino acid, and never functions as termination signal during ribosomal elongation.

Ref: Nelson and Cox, Lehninger Principles of Biochemistry, 7th Edition, Chapter 27 and Watson et al., Molecular Biology of the Gene, 7th Edition, Chapter 15 list TAA, TAG, TGA as stop codons and TGG as tryptophan, published by W.H. Freeman and Pearson.

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Immunotechnology & Physiology

Arrange the following vectors in the increasing order of their insert range : (A) Phage λ (B) YAC (C) M13 (D) Plasmid (E

Insert capacity increases progressively: M13 phage accommodates few kilobases, plasmids around 10 kb, lambda phage 15-25 kb, cosmids 35-45 kb via cos sites, and yeast artificial chromosomes hundreds kilobases to megabases, making this increasing order biologically accurate.

Ref: Brown, Molecular Cloning and Recombinant DNA Technology and Watson et al., Molecular Biology of the Gene, 7th Edition, Chapter 7 details cloning vector capacities for M13, plasmid, lambda, cosmid, and YAC vectors, published by Pearson.

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