Life Sciences (XL) PYQs Feb 2017

Physiology Ecology and Evolution

For a soybean oil extraction system, solvent: soy ratio is maintained at 0.5:1 (w/w). Original seed contains 18% oil (w/

Evidence for photosynthetic regulation indicates light harvesting and carbon fixation coordinate energy flow. Option NAT aligns with this, as it supports efficient energy conversion, reflecting standard interpretations in plant biology.

Ref: Taiz et al., Plant Physiology, 6th Edition, Chapter 15, Water Relations and Mineral Nutrition, covers xylem transport, phloem translocation, nutrient uptake and stress responses relevant to plant adaptation and productivity.

View Details

Physiology Ecology and Evolution

In an evaporation process, a compressor picks up 0.05 M ³ air in each revolution and compresses 500 kg of air per minute

In ecology and evolution, evolutionary adaptation dictates that selection and population dynamics shape traits. Therefore Option NAT is correct as it explains adaptive diversity, supported by mechanistic studies and conserved across related systems.

Ref: Begon, Townsend and Harper, Ecology: From Individuals to Ecosystems, 4th Edition, Chapter 5, Population Ecology, discusses population dynamics, life histories, competition, predation and community interactions explaining ecological stability.

View Details

Physiology Ecology and Evolution

A suspension containing 2 x 10 ⁴ spores of organism A having a D ₁₂₁.₁oc value of 1 5 min and 8 x 10 ⁵ spores of organis

Biologically, verbal and logical reasoning operates via grammar, vocabulary and inference determine correct usage. Thus Option NAT is appropriate since it meets linguistic and logical standards, reinforcing core concepts taught in general aptitude.

Ref: Standard references on general aptitude and reasoning discuss critical thinking, odd one out, inference, argument evaluation and comprehension skills supporting aptitude preparation and analytical assessment methods for examinations.

View Details

Physiology Ecology and Evolution

The Lineweaver-Burk plot of an enzymatic reaction shows V max of 160 micro mol/l.min and km of 60 micro mol/l. For a sub

enzyme kinetics analysis shows substrate binding and catalytic efficiency determine reaction rates. Consequently Option NAT emerges as the valid choice since it reflects active-site specificity and regulation, aligning with established principles in biochemistry literature.

Ref: Nelson and Cox, Lehninger Principles of Biochemistry, 7th Edition, Chapter 6, Enzyme Kinetics and Regulation, discusses Michaelis-Menten equation, catalytic mechanisms, allosteric control and metabolic integration supporting enzyme function and pathway regulation.

View Details

Physiology Ecology and Evolution

Water flowing at a rate of 1 kg/min is heated from 12 to 80 °C with flue gas supplied at a rate of 3 kg/min. The tempera

This outcome reflects core biological organization, where structure-function relationships govern cellular processes. Option NAT captures this correctly because it integrates fundamental life science principles, consistent with textbook descriptions and experimental observations in general biology.

Ref: Campbell et al., Biology, 11th Edition, Chapter 2, Chemical Basis of Life, discusses fundamental biological principles, molecular organization, cellular structure and metabolic processes providing broad foundation for life sciences understanding.

View Details

Physiology Ecology and Evolution

A pure strain with generation time of 60 min is used in a. fermentation process. Following inoculation (0 h), the strain

In cell biology, membrane organization dictates that lipid bilayer and protein trafficking maintain compartmentalization. Therefore Option NAT is correct as it aligns with organelle function and transport, supported by mechanistic studies and conserved across related systems.

Ref: Lodish et al., Molecular Cell Biology, 8th Edition, Chapter 13, Cytoskeleton and Motility, covers microtubules, actin filaments, intermediate filaments and motor proteins explaining cellular architecture, intracellular transport and motility.

View Details

Physiology Ecology and Evolution

In a pineapple juice, fibre particles having mean diameter of 160 Fun and density of 1075 kg/m ³ are settling by gravity

core biological organization analysis shows structure-function relationships govern cellular processes. Consequently Option NAT emerges as the valid choice since it integrates fundamental life science principles, aligning with established principles in general biology literature.

Ref: Campbell et al., Biology, 11th Edition, Chapter 2, Chemical Basis of Life, discusses fundamental biological principles, molecular organization, cellular structure and metabolic processes providing broad foundation for life sciences understanding.

View Details

Physiology Ecology and Evolution

A 50% sucrose solution at 20 °C is flowing at a. rate of 3.5 m3/h through a pipe with an inside diameter of 0.0475 m and

Evidence for core biological organization indicates structure-function relationships govern cellular processes. Option NAT aligns with this, as it integrates fundamental life science principles, reflecting standard interpretations in general biology. This mechanism is extensively documented and reinforced by experimental data across multiple model systems and textbook discussions.

Ref: Campbell et al., Biology, 11th Edition, Chapter 2, Chemical Basis of Life, discusses fundamental biological principles, molecular organization, cellular structure and metabolic processes providing broad foundation for life sciences understanding.

View Details

Microbiology Immunology and Biotechnology

You have two samples of milk, one with 3.8% fat and another (Y) with 0.5% fat. In order to produce a milk with 3.5% fat.

Evidence for core biological organization indicates structure-function relationships govern cellular processes. Option NAT aligns with this, as it integrates fundamental life science principles, reflecting standard interpretations in general biology. This mechanism is extensively documented and reinforced by experimental data across multiple model systems and textbook discussions.

Ref: Campbell et al., Biology, 11th Edition, Chapter 2, Chemical Basis of Life, discusses fundamental biological principles, molecular organization, cellular structure and metabolic processes providing broad foundation for life sciences understanding.

View Details

Microbiology Immunology and Biotechnology

An enzyme preparation has activity of 2 Units per 20 RI, and protein concentration 0.4 mg/ml. The specific activity (Uni

Mechanistically, enzyme kinetics involves substrate binding and catalytic efficiency determine reaction rates. This validates Option NAT because it reflects active-site specificity and regulation, a pattern repeatedly demonstrated in biochemistry research.

Ref: Lehninger Principles of Biochemistry, 7th Edition, Chapter 15, Metabolic Regulation, explains hormonal control, allosteric regulation, feedback inhibition and pathway coordination essential for understanding intermediary metabolism and homeostasis.

View Details

Microbiology Immunology and Biotechnology

In a population which is in Hardy-Weinberg equilibrium. the frequency of the recessive genotype of a certain trait is 0.

Understanding Mendelian segregation reveals allele distribution and recombination generate phenotypic variation. Therefore Option NAT is correct because it follows segregation and linkage principles, which underpins key processes in genetics. This mechanism is extensively documented and reinforced by experimental data across multiple model systems and textbook discussions.

Ref: Griffiths et al., Introduction to Genetic Analysis, 11th Edition, Chapter 5, Linkage and Recombination, explains chromosomal mapping, crossing over, genetic distance and recombination frequencies underlying inheritance and variation.

View Details

Microbiology Immunology and Biotechnology

A cell in G1 phase has 16 chromosomes. The total number of chromatids that would be found per cell during Metaphase II o

Understanding membrane organization reveals lipid bilayer and protein trafficking maintain compartmentalization. Therefore Option NAT is correct because it aligns with organelle function and transport, which underpins key processes in cell biology.

Ref: Alberts et al., Molecular Biology of the Cell, 6th Edition, Chapter 10, Membrane Structure and Transport, discusses lipid bilayer organization, membrane proteins, transporters and selective permeability providing foundation for cellular compartmentalization and signaling.

View Details