GATE XL Syllabus: Chemistry, Biochemistry, Botany, Microbiology and More

GATE XL exam pattern

Questions carry 1 or 2 marks each. A wrong pick on a one answer MCQ costs a third of its value; multiple select and numerical questions have no penalty but also no partial credit. Published reports differ slightly on how many questions sit in the chemistry part and in each optional section, so take the exact count from the official information brochure.

In recent cycles candidates have been able to pick their two optional sections during the exam after seeing the questions. Changing a section clears the answers already marked in it, so decide in the first few minutes.

XL0 Chemistry, the compulsory section

Ten units, pitched at the level of a first degree in the life sciences:

1. Atomic structure and periodic trends
2. Structure and bonding: VSEPR, hybridisation, MO and VB ideas, lattice energy, hard and soft acids and bases
3. s, p and d block elements and coordination complexes with crystal field ideas
4. Bioinorganic chemistry: oxygen carrying proteins, iron sulphur proteins, carbonic anhydrase, copper zinc superoxide dismutase
5. Chemical equilibria: colligative properties, solubility product, pH and buffers
6. Electrochemistry: conductance, cell potential, the Nernst equation
7. Reaction kinetics, including enzyme catalysis and inhibition
8. Thermodynamics: first and second laws, enthalpy, entropy, free energy and equilibrium constants
9. Organic reaction mechanisms and stereochemistry: substitution, elimination, addition and aromatic substitution
10. Chemistry of biomolecules: amino acids, proteins, nucleic acids, carbohydrates, lipids and purification methods

Biology students often find this the hardest 25 marks. The physical chemistry units (equilibria, kinetics, thermodynamics, electrochemistry) give the most numerical questions, and they are learnable with steady practice.

XL1 Biochemistry and XL2 Botany

XL1 Biochemistry

• Biomolecule structure, protein folding and model proteins such as myoglobin, haemoglobin and chymotrypsin
• Enzymes, kinetics with up to two substrates, coenzymes and metabolic regulation
• Metabolic pathways from glycolysis to fatty acid and nitrogen metabolism, photosynthesis, and associated disorders
• Analytical techniques: chromatography, centrifugation, electrophoresis, spectroscopy, sequencing, PCR and immunological methods including monoclonal antibodies
• Cell structure, membranes, transport, signalling, receptors and ion channels
• Replication, transcription, translation, DNA repair and gene regulation

XL2 Botany

• Plant systematics, the APG system and DNA barcoding
• Anatomy, development, flowering and seed formation
• Plant physiology and biochemistry: water relations, C3, C4 and CAM photosynthesis, stress and hormones
• Genetics and genomics, breeding, tissue culture and genome editing
• Economic botany, plant pathology, ecology and environment

XL3 Microbiology, XL4 Zoology and XL5 Food Technology

XL3 Microbiology

History of the field, methods (culture, microscopy, PCR, CRISPR Cas tools), taxonomy of bacteria, archaea, fungi, protozoa and viruses, prokaryotic cell structure, growth including quorum sensing and biofilms, metabolism, disease and immunity, antibiotics and resistance, microbial genetics, and microbial ecology with metagenomics.

XL4 Zoology

Animal diversity, evolution, genetics, biochemistry and molecular biology, cell biology, gene expression in eukaryotes, comparative anatomy and physiology, parasitology and immunology, developmental biology, ecology including Indian biodiversity hotspots, and animal behaviour.

XL5 Food Technology

Food chemistry and nutrition (with adulteration), food microbiology (D, Z and F values, spoilage, probiotics and prebiotics), food products technology from cereals to dairy and meat, and food engineering: mass and energy balance, heat and mass transfer, mechanical and thermal operations, and psychrometry.

What the revised file changes

The organising institute has revised syllabi across papers after five years. Comparing the new XL file with the previous one, the changes we noticed are:

• Sections are renamed XL0 to XL5 in place of the older letter codes.
• Chemistry gains a bioinorganic chemistry unit.
• Biochemistry is regrouped: immunology no longer has its own unit, with immune techniques now under analytical methods, and metabolic disorders are added.
• Microbiology adds CRISPR Cas methods, sporulation and quorum sensing.
• Food Technology names adulteration, probiotics and psychrometry explicitly.

Choosing your two optional sections

Pick the two sections that overlap with your degree, and prefer a pair that shares content. Biochemistry and Microbiology overlap on metabolism, molecular biology and techniques, which cuts your reading. Botany and Zoology share genetics, cell biology, ecology and evolution. Food Technology suits food science and dairy graduates, and pairs naturally with Microbiology.

A six month plan for the gate xl syllabus

1. Months 1 and 2: your stronger optional section, unit by unit, with short notes and previous questions after each unit.
2. Month 3: the second optional section, focusing on units not shared with the first.
3. Month 4: XL0 Chemistry, starting with physical chemistry numericals and then organic mechanisms.
4. Month 5: General Aptitude twice a week, plus mixed section tests.
5. Month 6: full 3 hour papers on screen with the virtual calculator, using our GATE previous papers guide.

Standard undergraduate textbooks in biochemistry, microbiology, botany or zoology and an NCERT class 11 and 12 chemistry revision are enough as a base. For the shared 15 aptitude marks read the GATE aptitude syllabus, and the other papers on the main GATE syllabus page.