GATE XL discipline:life-sciences PYQs & Answers — Page 10

Questions 91–100 of 1235. Imported answers require independent review unless marked reviewed.

Which of the following statements is/are NOT correct about the technique used in molecular biology?

Your answerSelect all correct options. You can choose more than one.

Southern blotting is used to detect specific DNA sequences

Northern blotting is used to detect RNA expression levels

Western blotting is used to detect proteins using antibodies

ELISA is used to detect specific DNA sequences directly without antibodies

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Assume that in the oxidative branch of the pentose phosphate pathway, each glucose-6-phosphate molecule generates the following products: 2 molecules of NADPH, 1 molecule of CO₂ and 1 molecule of ribulose-5-phosphate.

If 30 molecules of glucose-6-phosphate enter this pathway, and you randomly draw one molecule from the products of the pathway, the probability that this molecule is NADPH is __________ (round off to one decimal place).

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Muscle performance is positively correlated with Darwinian fitness. The graph below describes the relationship between mean environmental temperature and muscle performance for two closely related lizard species, one living in temperate areas (solid line) and another living in tropical areas (dashed line). Current mean environmental temperatures are marked with vertical dotted lines at (i) for the temperate species and (ii) for the tropical species. If mean environmental temperatures at both locations increase at a steady rate over time, which one of the following is most likely to occur in the near future?

Your answerChoose one option.

Temperate and tropical species will be negatively impacted to the same extent

Temperate species may be positively impacted but tropical species will be negatively impacted

Temperate species will be negatively impacted but tropical species will be positively impacted

Neither temperate nor tropical species will be impacted

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In eukaryotic cells, a mutation reduces the enzymatic activity of pyruvate dehydrogenase by 90%, without affecting expression. Under aerobic conditions, which one of the following metabolic changes is most expected in cells with the mutation compared to cells without?

Your answerChoose one option.

Mutated cells will accumulate pyruvate and increase lactate production, despite oxygen being available

Mutated cells will have higher metabolic flux through Krebs cycle, resulting in higher NADH yield

This mutation will have no effect on metabolism

Mutated cells will have depleted levels of pyruvate and lactate, despite oxygen being available

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Which one of the following describes the role of enhancers in eucaryotic gene regulation?

Your answerChoose one option.

Enhancers always lie immediately upstream of the promoter and function only in a fixed orientation

Enhancers can act at variable distances from the promoters and may function upstream, downstream, or within introns of genes

Enhancers directly bind to RNA polymerase II to initiate transcription

Enhancers overlap with the RNA polymerase II binding site

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Retes are networks of outgoing arteries and returning veins that create a counter-current pattern. Retes in the flippers of seals that live in temperate areas function as

Your answerChoose one option.

sensitivity enhancers to increase pain sensitivity in the flippers.

metabolism blockers to prevent excess nutrients from being made in the flippers.

heat blocks to prevent body heat from being lost to the flippers.

pressure enhancers to spike blood pressure in the flippers.

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Researchers measure the activity of an enzyme in the presence of an inhibitor. They observe that •

of the enzyme remains unchanged at saturating substrate concentration •

increases compared to uninhibited enzyme Which type of inhibition is most consistent with these observations?

Your answerChoose one option.

Competitive inhibition

Non-competitive inhibition

Irreversible inhibition

Substrate inhibition

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Below are the numbers of individuals of migratory green warblers and the frequencies of three genotypes at a single locus for this species. F refers to the allele for faster migration and S to the allele for slower migration.

	FF	FS	SS	Total
Number of individuals	35	20	10	65
Genotype frequencies	0.54	0.30	0.16	1

What are the allele frequencies of F and S? (round off to 2 decimal places)

Your answerChoose one option.

Allele frequency of F = 0.69 and allele frequency of S = 0.31

Allele frequency of F = 0.59 and allele frequency of S = 0.41

Allele frequency of F = 0.31 and allele frequency of S = 0.69

Allele frequency of F = 0.50 and allele frequency of S = 0.50

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A drug was developed to inhibit histone acetyl transferase in eukaryotic cells. Cells treated with this drug have more compact chromatin and show reduction in transcription of several genes. Which one of the following statements best explains why the drug has this effect?

Your answerChoose one option.

Histone acetylation increases positive charge on histones, thereby tightening DNA binding and repressing transcription

Histone H1 directly binds the nucleosome core and its acetylation directly causes nucleosome disassembly

Histone acetylation neutralizes positive charge on histones, thereby loosening DNA-histone interactions and promoting transcription

Euchromatin is normally condensed, so reduced acetylation of histones converts it into a transcriptionally active state

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Two species of snakes, Species P and Species Q, have overlapping geographic distributions. Species P mainly eats rodents, whereas Species Q mainly eats invertebrates. Which one or more of the following terms describe(s) the process of speciation for these two species?

Your answerSelect all correct options. You can choose more than one.

Sympatric speciation

Parapatric speciation

Allopatric speciation

Niche differentiation

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GATE XL discipline:life-sciences PYQs

Question 91

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Question 100