List of top Life Science Questions asked in GATE XL

Which of the following antibiotics is/are isolated from Streptomyces spp.?

Which of the following statements about the primary and secondary adaptive immune responses to an antigen is/are correct?

The spontaneous, and induced mutations in bacteria can be distinguished by

Determine the correctness or otherwise of the following Assertion [a] and the Reason [r]. Assertion [a]: Endospore can survive heat that would rapidly kill vegetative cells of the same species.
Reason [r]: In endospore, the protoplasm is reduced to minimum volume as a result of the accumulation of calcium-dipicolinic acid complexes and small acid-soluble spore proteins, which forms a cytoplasmic gel and a thick cortex.

Which one of the following conjugations will result in formation of merodiploids?

Which of the following genus is/are a spirochete(s)?

Which of the following is/are non-membrane bound inclusion bodies?

Which one of the following is NOT correct about antibiotic resistance mechanism in microbes?

Which one of the statements about bacterial flagella is correct?

Microbial plastics are made from:

The correct sequence of metabolic intermediates in the Krebs cycle is:

Catabolite repression in bacteria is regulated by the concentration of

Phagocytosis was first described by

Which one of the following statements about batch culture of microbes is NOT correct?

Blue light can directly induce opening of stomata. Blue light also triggers photosynthesis in the guard cells, which indirectly induces stomatal opening. Which one or more of the following experimental approaches would test the direct effect of blue light on stomatal opening?

A cytoplasmic male-sterile female plant with the restorer (nuclear) genotype rr is crossed to a male-fertile male plant with the genotype RR. Both RR and Rr can restore the fertility, whereas rr cannot. When an F1 female plant with Rr genotype was test-crossed to a male-fertile male plant with the rr genotype, the percentage of the population that is male fertile would be _______. (Answer in integer)

Monkeypox is caused by a

Which one of the following converts sulfate to hydrogen sulfide?

Central vascular cylinder or stele consists of the primary vascular system (xylem and phloem) and the associated fundamental tissue. Match the schematics of stele in Group I (xylem shown in green, and phloem shown as with their respective types in Group II. \includegraphics[width=0.75\linewidth]{image58.png}

Consider four observations about the FT gene and flowering transition in the shoot apical meristem (SAM) of Arabidopsis thaliana:
(i) The FT promoter is active in leaves alone.
(ii) The ft null mutation causes delayed flowering of the SAM.
(iii) Expressing a recombinant FT protein fused to a nuclear localization signal (NLS) under the endogenous promoter does not rescue the delayed-flowering phenotype of the ft null mutant.
(iv) Downregulation of FT transcript in the SAM by RNAi in a wild-type background does not alter flowering.
Which conclusion best explains these observations?

Which one or more of the following statements is/are NOT CORRECT with respect to pollen development in angiosperm?

Regulation of phosphoenolpyruvate carboxylase (PEPCase) governs CO2 fixation in both C4 and CAM (crassulacean acid metabolism) plants. Which one or more of the following statements with respect to PEPCase activity is/are CORRECT?

Which one or more processes listed below DOES NOT produce carbon dioxide during fermentation?

Although Pseudomonas syringae infection in plants is actively inhibited by the endogenous salicylic acid (SA) of host origin, a successful infection is still established because the bacterium secretes coronatine, an effector molecule. Which one of the following best describes the mode of action of coronatine?

Which one of the following statements on Casparian strips is correct?