Exams, GATE-XL

GATE Life Sciences (XL): Important Topics

GATE Life Sciences (XL) has remained a well attended examination with a good (long) history behind it. A lot of Biology/Biotech/Life Sciences students appear for it every year, apart from the recently (2010) introduced GATE BT (Biotechnology). One can find sufficient number of previous year papers for GATE XL from various online archives. Here’s an attempt to supplement that information with some tips regarding important topics for GATE Life Sciences (XL). We appreciate one of the students “satgurunathan” who asked for this information (Click here for his comment), following which this information was pro-actively compiled.


I will write in the order of importance. So, the 1st topic will have most importance.

  1. Chemical Equilibria (Be thorough on pH concepts, pKa and pKb concepts, Solubility of salts, Equivalence point, what are buffers, Handerson equation and common-ion effect )
  2. Reaction Kinetics (First order kinetics , Michaelis-Menten, and how to determine order of a reaction and activation energy)
  3. Thermodynamics (Formula for relation between Free energy change and equilibrium constant; EMF and free energy, basics of coexistence curve)
  4. Organic (Basic understanding of SN1, SN2, E1, E2 (in terms of their difference from one another; with special focus on some key examples, conceptual understanding of aromatic electrophilic substitution (special focus on examples), Markonikoff rule,  Primary alcohol chemical test (Lucas), Tests for Aldehydes, Iodoform test)
  5. Electrochemistry (EMF and Nernst Equation)
  6. Co-ordination Complexes (special focus on magnetic properties, coordinate complexes of biological significance; and on EDTA)
  7. Hybridization, Resonance and Dipole moment, Born-Haber Cycle
  8. Optical , geometrical isomerism, and tautomerism



Again, these are in the order of their importance.

1. Structural and functional difference between Major histocompatibilty complexes, Complement system (throughly study similarity and differences between Classical and Alternative Pathway; and Classical and Lectin Pathway); thoroughly study Antibody Structure (Special focus on functions of IgG,M and A). Which antibodies are targeted for detecting viral infections like Dengue?

2. ATP sheet of Glycolysis, Kreb’s cycle and ETC (i.e how many ATPs, NADH, NADPH, GTPs etc formed/consumed in these cycles).

3. Fatty Acid Metabolism (special focus on understanding role of Acyl CoA). Be aware of the term  Beta Oxidation and why is it called so.

4. PS1 and PSII systems (do memorize theri wavelengths of absorption), Z scheme and absorption spectrum of Chlorophyll-a, Chlorophyll-b and carotenoids. Thus analyze the constituents of PS1 and PSII.

5. Difference between Prokaryotic and Eukaryotic central dogma; Structure and function of DNA polymerase; Types of Topoisomerases and their functions, methods and mechanisms to permeate DNA into a cell, vectors for DNA transfer (special focus on AAVs), GPCR (special focus on components of G-proteins and their function), thoroughly study PCR (it’s IITK’s favorite topic!)

6. Ion channels, Protein mediated transport and ABC transporters (basic understanding of these topics needed; not deep details)



1. Model organisms in Developmental biology, The genetics of axis specification in Drosophila, basic understanding of ectoderm, endoderm and mesoderm (along with role), Neural crest cells, Gastrulation and Neurulation (should know as terms), Reporter genes, Biochemical methods for studying gene expression, The roles of the Mediator complex and Cohesin in regulating gene transcription,ZP2 as the major mammalian sperm receptor, Transcription factors and microRNAs in pluripotency, Quiescent and active stem cells, Tbx genes, Notch, EGFR, and cilia, ChiP-Seq methodology and Poised chromatin

2. Hormones and their actions, Role of various vitamins (focus on deficiency diseases), Enzyme Catalysis, Lac operon and Trp operon in complete detail.

3. Histone proteins and their role, study about state of genes (active or inactive) in various condensed/relaxed  conformations of DNA/chromosome, study in detail about Nucleosomes, detailed study of a chromosome’s structure; study Golgi bodies and ER.

4. Osmoregulation, Nephrons, Nervous system (cell structure, function , neurotransmitters, polarized vs unpolarized neurons), Heart structure, Functional units of lungs, throughput of kidneys, enzymes secreted in various organs ofdigestive system.


5. Diseases caused by various protozoans and helminths, population dynamics, species diversity, pheromones.

Keep WATCHING this SPACE for further updates on other Subjects



  1. satgurunathan

    thank you so much for your best efforts and valuable time…
    important topics for biochemistry and zoology…?
    i used lehninger and voet & voet for biochemistry…
    for zoology used various books for a specific topic for example kuby immunology and Gilbert developmental biology etc…

    • Sunil Nagpal

      Hi satgurunathan,
      You are most welcome! I’ll keep adding the topics with time (have added Biochemistry today).
      Both Lehninger and Voet are ideal books. Kuby is bible of Immunology (so good choice!) and so is the case of Gilbert’s developmental biology. Your choice of books has been nice. Considering the short time left for GATE, I would recommend being thorough on previous year papers as well.

      Best Wishes


  2. manisha tikka

    Thank u sir could u plz suggest important topic for zoology ?

  3. smriti sinha

    please suggest me ideal books for whole syllabus life science and general aptitude.

  4. Gowtham Balasubramanian

    My brother has Joined B.Sc Biotechnology.Whether he is eligible to write Gate lifesciences(XL) by his final year.If so,how he should Prepare..?Please reply

  5. Sir please suggest important topic for Microbiology

  6. Shalini Jain

    I have secured 39 marks in GATE 2018 in Life sciences (XL) with an AIR of 596 and gate score as 524. What to do next. Give me some guidance?


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