Life Sciences
GATE XL topic:biology PYQs
Build your understanding with focused practice from past exam papers.
Questions 191–200 of 1235. Imported answers require independent review unless marked reviewed.
Question 69
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Robert Koch used a meat-infused nutrient medium for which one of the following purposes?
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A penicillin sensitive Escherichia coli population is exposed to a lethal dose (200 μg/ml) of penicillin. Assuming density-independent mortality, which one of the following relationships would describe the number of surviving bacteria (N) over time (T)?
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A bacterium obtains energy from a chemical source by the oxidation of reduced
, with
as the principal carbon source. Which one of the following nutritional groups does this bacterium belong to?Your answerChoose one option.
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The origin of the Escherichia coli chromosome on the genetic map is shown below.
Bidirectional replication is a feature of this system and both replication forks move at the same rate. Which one of the following sequences of replication of the genes is correct?
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Which of the following sites is/are the location(s) of ATP generation through oxidative phosphorylation in Escherichia coli?
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The adaptive immune response in an animal involves the generation of antibodies against an invading bacterial pathogen. The following graph presents antibody titer levels in an animal exposed twice to the pathogen.
Which one of the following options correctly pairs antibodies to peak I and peak II in the graph?
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Carl Woese established that short subunit rRNA sequences can be used to reveal evolutionary relationships between various organisms. Based on this, which one of the following options is the established phylogenetic arrangement of the three domains of life?
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Correctly match the viruses listed in Column I with the nature of their corresponding genetic materials listed in Column II.
Column I | Column II
P. Bacteriophage lambda | i. dsDNA
Q. Bacteriophage M13 | ii. ssDNA
R. Coronavirus | iii. ssRNA
S. Reovirus | iv. dsRNA
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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 77
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A culture of lac
Escherichia coli is grown in a medium lacking lactose or any other β-galactoside. The response of the lac operon upon induction by lactose can be monitored by measuring the levels of lac mRNA, β-galactosidase enzyme and permease enzyme. Which one of the following profiles correctly captures the on-off response to lactose? 
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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 78
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Which option(s) correctly match(es) the structures in a bacterial cell (Column I) with their corresponding functions (Column II).
Column I | Column II
P. Cell wall | i. Protection from osmotic stress
Q. Fimbriae | ii. Attachment to surfaces
R. Flagella | iii. Motility
S. Pili | iv. Transfer of genetic material
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