Life Sciences
GATE XL year:2018 PYQs
Build your understanding with focused practice from past exam papers.
Questions 81–90 of 125. Imported answers require independent review unless marked reviewed.
Question 16
Open questionXL-SMCQ2 marksNeeds review
Which of the following combinations would improve the resolution of a microscope?
(i) Increasing the half aperture angle of the objective lens
(ii) Decreasing the wavelength of the illumination source
(iii) Decreasing the numerical aperture of the objective lens
(iv) Decreasing the refractive index of immersion medium
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Open questionXL-SNAT2 marksNeeds review
Active transport involves the movement of a biomolecule against a concentration gradient across the cell membrane using metabolic energy. If the extracellular concentration of a biomolecule is 0.005M and its intracellular concentration is 0.5M, the least amount of energy that the cell would need to spend to transport this biomolecule from the outside to the inside of the cell is ________ kcal/mol (up to 2 decimal points).
(Temperature T = 298K and universal gas constant R= 1.98 cal/mol·K)
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Open questionXL-SNAT2 marksNeeds review
A continuous cell culture being carried out in a stirred tank reactor is described in terms of its cell mass concentration X and substrate concentration S. The concentration of the substrate in the sterile feed stream is S_F = 10 g/L and yield coefficient Y_{x/s} = 0.5. The flow rates of the feed stream and the exit stream are equal (F=5 mL/min) and constant. If the specific growth rate (h⁻¹) μ = \frac{0.3\ S}{(1+S)}, the steady state concentration of S is ____ g/L (up to 1 decimal point).
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Open questionXL-SNAT2 marksNeeds review
The initial concentration of cells (N₀) growing unrestricted in a culture is 1.0×10⁶ cells/mL. If the specific growth rate (μ) of the cells is 0.1 h⁻¹, the time required for the cell concentration to become 1.0×10⁸ cells/mL is ________ hours (up to 2 decimal points).
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Open questionXL-SNAT2 marksNeeds review
The following stoichiometric equation represents the conversion of glucose to lactic acid in a cell:
Glucose + 2Pi + 2ADP → 2Lactate + 2ATP + 2H₂O
If the free energy of conversion of glucose to lactic acid alone is ΔG⁰ = −4700 cal/mol, the efficiency of energy transfer is ______ % (up to 1 decimal point).
(ΔG⁰ for ATP hydrolysis is −7.3 kcal/mol)
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 1
Open questionXL-TMCQ1 markNeeds review
Animals belonging to phylum Echinodermata are closer to chordates than other invertebrate phyla. Which ONE of the following reasons can account for this relatedness?
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A zoologist recovered some tissue from preserved skin of a woolly mammoth. Further genetic analysis requires DNA isolation and increase its amount. Which ONE of the following techniques would be most useful for increasing the amount of DNA?
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Open questionXL-TMCQ1 markNeeds review
In a chemical reaction where the substrate and product are in equilibrium in solution, what will occur if an enzyme is added?
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Open questionXL-TMCQ1 markNeeds review
Tay-Sachs disease is a human genetic disorder that is associated with defects in which ONE of the following cellular organelles?
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Open questionXL-TMCQ1 markNeeds review
Increase in the existent population of grey peppered moth, Biston betularia, during industrial revolution in Britain is an example of which ONE of the following evolutionary processes?
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