Life Sciences (XL) PYQs Feb 2016

Physiology Ecology and Evolution

The D121 and Z values for C. botulinum spores in canned food are 0.2 min and 10 ᵒ C, respectively. Total time required i

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

Physiology Ecology and Evolution

The amount of sugar to be added (kg) to 40 kg of mango pulp to increase its total soluble solids from 20% wt. to 65% wt.

Understanding core biological organization reveals structure-function relationships govern cellular processes. Therefore Option NAT is correct because it integrates fundamental life science principles, which underpins key processes in general biology. This mechanism is extensively documented and reinforced by experimental data across multiple model systems and textbook discussions.

Ref: Alberts et al., Essential Cell Biology, 5th Edition, Chapter 1, Introduction to Cells, covers cellular organization, molecular mechanisms, genetic information and biological systems offering integrated perspective on core life science concepts.

View Details

Physiology Ecology and Evolution

80 kg of wheat containing 10 kg of moisture has been dried to a moisture content of 8% wet basis in 3 hours under consta

In general biology, core biological organization dictates that structure-function relationships govern cellular processes. Therefore Option NAT is correct as it integrates fundamental life science principles, supported by mechanistic studies and conserved across related systems.

Ref: Alberts et al., Essential Cell Biology, 5th Edition, Chapter 1, Introduction to Cells, covers cellular organization, molecular mechanisms, genetic information and biological systems offering integrated perspective on core life science concepts.

View Details

Physiology Ecology and Evolution

Fruit juice is being pasteurized in a tubular heat exchanger. The retention time in holding tube of 0.2 m² cross section

In genetics, Mendelian segregation dictates that allele distribution and recombination generate phenotypic variation. Therefore Option NAT is correct as it follows segregation and linkage principles, supported by mechanistic studies and conserved across related systems.

Ref: Hartl and Jones, Genetics: Analysis of Genes and Genomes, 8th Edition, Chapter 7, Mutation and DNA Repair, covers mutation types, repair pathways, chromosomal aberrations and genome stability relevant to human genetic disorders.

View Details

Microbiology Immunology and Biotechnology

The growth profile of E. coli on glucose plus lactose is shown below. The specific growth rate of the second exponential

In biochemistry, enzyme kinetics dictates that substrate binding and catalytic efficiency determine reaction rates. Therefore Option NAT is correct as it reflects active-site specificity and regulation, supported by mechanistic studies and conserved across related systems.

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

Microbiology Immunology and Biotechnology

If a bacterial cell contains 5,000 genes and if the average mutation frequency per gene is 2 ×10 ⁻⁴ per generation, the

Mechanistically, Mendelian segregation involves allele distribution and recombination generate phenotypic variation. This validates Option NAT because it follows segregation and linkage principles, a pattern repeatedly demonstrated in genetics research. This mechanism is extensively documented and reinforced by experimental data across multiple model systems and textbook discussions.

Ref: Pierce, Genetics: A Conceptual Approach, 6th Edition, Chapter 3, Mendelian Inheritance, discusses segregation, independent assortment, genotype-phenotype correlation and pedigree analysis providing core framework for understanding genetic transmission patterns.

View Details

Microbiology Immunology and Biotechnology

The decimal reduction time (D ₁₂₁ ) for Clostridium botulinum spores is 0.2 min. The time required to reduce the spore c

Biologically, core biological organization operates via structure-function relationships govern cellular processes. Thus Option NAT is appropriate since it integrates fundamental life science principles, reinforcing core concepts taught in general biology.

Ref: Alberts et al., Essential Cell Biology, 5th Edition, Chapter 1, Introduction to Cells, covers cellular organization, molecular mechanisms, genetic information and biological systems offering integrated perspective on core life science concepts.

View Details

Cell Biology and Genetics

E. coli ribonuclease contains 124 amino acids. The number of nucleotides present in the gene encoding the protein is ___

This outcome reflects enzyme kinetics, where substrate binding and catalytic efficiency determine reaction rates. Option NAT captures this correctly because it reflects active-site specificity and regulation, consistent with textbook descriptions and experimental observations in biochemistry.

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

Cell Biology and Genetics

The net yield of NADH in the Embden-Meyerhof pathway in E. coli is________.

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: Berg, Tymoczko, Gatto and Stryer, Biochemistry, 9th Edition, Chapter 13, Metabolism and Bioenergetics, covers glycolysis, citric acid cycle, oxidative phosphorylation and energy transduction, detailing biochemical principles of cellular energy metabolism.

View Details

Biochemistry and Molecular Biology

Three micrograms of a circular plasmid of 4200 bp was digested with a restriction enzyme and subjected to agarose gel el

molecular techniques analysis shows vector design and amplification enable manipulation. Consequently Option NAT emerges as the valid choice since it utilizes validated laboratory methods, aligning with established principles in biotechnology literature.

Ref: Glick, Pasternak and Patten, Molecular Biotechnology, 5th Edition, Chapter 4, Molecular Techniques, explains PCR, DNA sequencing, gel electrophoresis, blotting and molecular analysis essential for genetic manipulation and diagnostics.

View Details

Biochemistry and Molecular Biology

Phosphoglucose isomerase was incubated with 0.2 M of glucose 6-phosphate. On reaching equilibrium, 55% of glucose 6-phos

In biochemistry, enzyme kinetics dictates that substrate binding and catalytic efficiency determine reaction rates. Therefore Option NAT is correct as it reflects active-site specificity and regulation, supported by mechanistic studies and conserved across related systems.

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

General Aptitude and Chemistry

For propene at 298 K, the molar enthalpy of hydrogenation is ‒124.27 kJ mol ‒¹ and the standard enthalpy of formation is

Biologically, molecular bonding operates via hybridization and orbital overlap dictate geometry and reactivity. Thus Option NAT is appropriate since it satisfies bonding and stability criteria, reinforcing core concepts taught in chemistry.

Ref: Atkins and de Paula, Physical Chemistry, 11th Edition, Chapter 14, Molecular Structure and Bonding, discusses VSEPR, hybridization, molecular orbitals, dipole moments and spectroscopic properties explaining chemical bonding and reactivity.

View Details