Life Sciences
GATE XL format:nat PYQs
Build your understanding with focused practice from past exam papers.
Questions 151–160 of 244. Imported answers require independent review unless marked reviewed.
Question 19
Open questionXL-SNAT2 marksNeeds review
A 100 μl aliquot (
dilution) of the bacterial culture plated on the nutrient agar gave 4 colonies. The bacterial stock concentration (in million cells/ml, rounded off to one decimal place) is _____.Log in to check the answer
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Open questionXL-SNAT2 marksNeeds review
A continuous bacterial culture carried out in a chemostat is set to a flow rate of 40 ml/hr. The culture volume is equivalent to that of a cubical container having 10 cm sides. The dilution rate (in hr⁻¹, rounded off to two decimal places) of this system is _____.
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Open questionXL-TNAT2 marksNeeds review
In Drosophila, the red eye phenotype (W) is dominant over the recessive white eye mutant (w). In a mixed population of red and white eye flies of 10,000 individuals, 3,600 flies were white eyed. The percentage of the heterozygous red eye flies in this population is _____________.
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Open questionXL-UNAT1 markNeeds review
The velocity of 2.2 μm diameter fat particles inside a centrifuge, running at 600 rpm and 20 °C, is 0.25 mm s⁻¹. The velocity of 1.5 μm diameter fat particles inside the same centrifuge running at 750 rpm and same temperature (round off to 2 decimal places) will be ______ mm s⁻¹.
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Open questionXL-UNAT1 markNeeds review
The initial population of a bacterial strain increases from 1×10⁴ cells per mL to 1×10⁶ cells per mL in 120 minutes. The generation time for this strain (round off to 2 decimal places) is ______ minutes.
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Open questionXL-UNAT2 marksNeeds review
An orange juice flowing at 0.80 kg s
enters a counter current double pipe heat exchanger at 20 °C and leaves at 72 °C. Inlet and outlet temperatures of the hot water used as heating medium in the exchanger are 81 °C and 74 °C, respectively. The specific heat of the orange juice is 3.74 kJ kg
K
and overall heat transfer coefficient is 492 W m
K
. The heat transfer surface area (round off to 2 decimal places) will be ______ m
.Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 4
Open questionXL-PNAT1 markNeeds review
The total number of tautomers for the following molecule (including the structure provided below) is ____.
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Open questionXL-PNAT1 markNeeds review
The total number of stereoisomers possible for the following structure is ____
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Open questionXL-PNAT2 marksNeeds review
A protein in denatured state (D) is in equilibrium with native state (N).
D ⇌ N
At 360 K, both N and D states are equally populated. If the standard entropy change for the reaction at this temperature ΔS° = −139 J K⁻¹ mol⁻¹, then the corresponding standard enthalpy change ΔH° for the reaction in kJ mol⁻¹ (rounded off to one decimal place) is _____.
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Open questionXL-PNAT2 marksNeeds review
The pH of a 1.0 L buffer solution containing 0.2 mol of acetic acid (CH₃COOH) and 0.3 mol of sodium acetate (CH₃COONa) is 5.0. The Kₐ of acetic acid is P × 10⁻⁵, where the numerical value of P (rounded off to one decimal place) is ____.
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