Quantitative Aptitude & Logical Reasoning

Quantitative Aptitude & Logical Reasoning

The function of the hepatic portal circulation is to :

Hepatic portal vein collects nutrient-rich blood from intestines and spleen delivering it to liver for processing, glycogen storage, detoxification and protein synthesis. It does not carry toxins to urinary system, distribute hormones broadly or transfer bile from pancreas.

Ref: Guyton and Hall, Textbook of Medical Physiology, 14th Edition, Chapter 65 Liver, describes hepatic portal circulation collecting absorbed nutrients from intestine for metabolic processing and storage in liver, published by Elsevier.

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Quantitative Aptitude & Logical Reasoning

Given below are two statements : Statement I : In Anaphase I, homologous chromosomes separate while sister chromatids re

In anaphase I homologous chromosomes separate with sister chromatids staying together, halving chromosome number. Chromosomes aligning at metaphase plate occurs in metaphase, not anaphase II where sister chromatids separate. Thus statement I correct, statement II incorrect, validating option C.

Ref: Bruce Alberts et al., Molecular Biology of the Cell, 6th Edition, Chapter 17 Cell Cycle and Mitosis, clarifies anaphase I separates homologs while metaphase plates align chromosomes and anaphase II separates sisters, published by Garland Science.

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Quantitative Aptitude & Logical Reasoning

Which of the following is not a function of the lysosomes?

Lysosomes are acidic organelles for degradation of worn-out organelles, engulfed exogenous material and autophagy, often called suicidal bags. ATP production is mitochondrial oxidative phosphorylation, not lysosomal, so power generating units is not a lysosomal function.

Ref: Bruce Alberts et al., Molecular Biology of the Cell, 6th Edition, Chapter 13 Lysosomes, states lysosomes digest worn-out components and exogenous substances but mitochondria generate ATP as powerhouses, published by Garland Science.

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Quantitative Aptitude & Logical Reasoning

Identify the correct order in which extra-cellular signals are transmitted. (A) Adenylate cyclase (B) cAMP (C) Protein k

Extracellular signals activate G-protein coupled receptors stimulating adenylate cyclase to synthesize cAMP from ATP. cAMP then activates protein kinase A, which phosphorylates downstream targets. Hence sequence is adenylate cyclase, cAMP, protein kinase A for this secondary messenger cascade.

Ref: David Nelson and Michael Cox, Lehninger Principles of Biochemistry, 8th Edition, Chapter 12 Biosignaling, outlines GPCR activation of adenylate cyclase producing cAMP activating protein kinase A cascade, published by W.H. Freeman.

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Quantitative Aptitude & Logical Reasoning

A study is done on a mammalian cell line that has a doubling time of 24 hours. These cells are synchronized in G1 and th

Cells in G1 labeled continuously with BrdU incorporate heavy thymidine analog into new DNA. After one doubling all duplexes are H/L. After second doubling, H/L chromatids produce 50% H/L and 50% H/H upon semiconservative replication, yielding mixed density pattern.

Ref: Bruce Alberts et al., Molecular Biology of the Cell, 6th Edition, Chapter 5 DNA Replication, explains semiconservative replication and BrdU heavy-light labeling producing H/L and H/H patterns after two generations in CsCl gradients, published by Garland Science.

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Quantitative Aptitude & Logical Reasoning

Identify which of the following tests is the most convincing to identify a gene as oncogene or tumor suppressor gene.

Convincing oncogene demonstration requires gain-of-function transgenic mice developing tumors when candidate oncogene overexpressed, while tumor suppressor needs loss-of-function knockout mice developing tumors. Opposite combinations would not show oncogenic phenotype, making transgenic oncogene plus knockout suppressor correct.

Ref: Robert Weinberg, The Biology of Cancer, 2nd Edition, Chapter 3 Oncogenes and Tumor Suppressors, discusses transgenic overexpression of oncogenes and knockout of tumor suppressors as gold standard functional tests, published by Garland Science.

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Quantitative Aptitude & Logical Reasoning

The function of the 3′ to 5′ exonuclease activity of a DNA polymerase is to:

DNA polymerases possess 3ʹ to 5ʹ exonuclease for proofreading, removing mispaired nucleotides immediately after incorporation from growing strand. This improves replication fidelity by excising incorrect bases, not removing 5ʹ ends, template lesions or creating blunt ends.

Ref: David Nelson and Michael Cox, Lehninger Principles of Biochemistry, 8th Edition, Chapter 25 DNA Replication, describes DNA polymerase 3 to 5 exonuclease proofreading removing incorrect nucleotides during synthesis, published by W.H. Freeman.

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Quantitative Aptitude & Logical Reasoning

Given below are two statements regarding Major Histocompatibility Complex (MHC). Statement I: MHC I contains two differe

MHC class I consists of heavy α chain with three domains plus noncovalently associated β2-microglobulin, not α plus β chain as in MHC II. It is expressed on all nucleated cells presenting endogenous antigens, so statement I false, II true.

Ref: Peter Parham, The Immune System, 5th Edition, Chapter 6 MHC and Antigen Presentation, details MHC I structure of alpha chain plus beta2 microglobulin and expression on all nucleated cells, published by Garland Science.

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Quantitative Aptitude & Logical Reasoning

The mechanism by which B cells ensure that only one heavy and one light chain allele is translated is referred to as

Allelic exclusion ensures each B cell expresses only one parental heavy-chain and one light-chain allele after successful VDJ recombination, preventing dual specificity. This is mediated by feedback inhibition of recombination activating genes, distinct from co-dominance or isotypic selection mechanisms.

Ref: Abul Abbas et al., Cellular and Molecular Immunology, 10th Edition, Chapter 8 B Cell Development, explains allelic exclusion ensuring single heavy and light chain expression after productive VDJ recombination, published by Elsevier.

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Quantitative Aptitude & Logical Reasoning

All of the following acts as anaphylotoxins EXCEPT

Anaphylatoxins C3a, C4a and C5a released during complement activation increase vascular permeability and mast cell degranulation. C6 is part of membrane attack complex components C5b-9, but no C6a fragment has anaphylatoxin activity, so C6a exception is correct.

Ref: Kenneth Murphy, Janeway's Immunobiology, 9th Edition, Chapter 2 Complement System, defines C3a C4a C5a as anaphylatoxins and explains C6 participates in MAC not anaphylatoxin, published by Garland Science.

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Quantitative Aptitude & Logical Reasoning

Which of the following connective tissues has a matrix of collagen and elastin fibres in a rubbery ground substance?

Cartilage possesses chondrocytes embedded in matrix rich in collagen type II and elastin fibers within rubbery ground substance of proteoglycans. Adipose stores fat, bone has mineralized matrix, blood has fluid plasma, not rubbery collagen-elastin matrix.

Ref: Anthony Mescher, Junqueira's Basic Histology Text and Atlas, 15th Edition, Chapter 7 Cartilage, describes cartilage matrix with collagen and elastin fibers in rubbery proteoglycan ground substance, published by McGraw-Hill Education.

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Quantitative Aptitude & Logical Reasoning

Match List I with List II. List I List II (A) Mechanoreceptor (I) Detects change in water volume of a solution (B) Nocic

Mechanoreceptors detect pressure, touch, position and acceleration. Nociceptors detect painful tissue damage. Osmoreceptors sense osmolarity changes and water volume. Thermoreceptors respond to heat and cold, making mapping A-IV, B-III, C-I, D-II anatomically correct.

Ref: Guyton and Hall, Textbook of Medical Physiology, 14th Edition, Chapter 46 Sensory Receptors, classifies mechanoreceptors, nociceptors, osmoreceptors and thermoreceptors by stimulus modality and function, published by Elsevier.

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