GATE — Life Sciences (XL) with Section U Food Technology

India · IITs and IISc on rotation (2026: IIT Guwahati) · pg

545practice questions written to this syllabus
34subjects

Format

Computer-based, 3 hours, 100 marks: General Aptitude 15, Section P Chemistry (compulsory) 25, and two optional sections of 30 marks each. MCQ, MSQ and NAT; −1/3 or −2/3 on wrong MCQs only; no partial credit on MSQ.

Sections

Over the years

Paper structure from the GATE 2026 question-paper-pattern page and the XL combined syllabus PDF (both read 3 Oct 2026). Used by dairy and food technology graduates for M.Tech admission (IITs, NITs and other institutes) and some PSU screening. Dairy is one block of Section U, not a paper of its own.

Official source: https://gate2026.iitg.ac.in/doc/GATE2026_Syllabus/XL-2026_Combined_Syllabus.pdf

Subjects this exam draws on

Mathematics & Statistics for Dairy Science34 questionsBiochemistry for Dairy Science69 questionsGeneral Microbiology74 questionsHuman Nutrition & Dairy in the Diet63 questionsMilk Lipids2 questionsLactose, Milk Salts & Vitamins2 questionsChemistry of Dairy Products1 questionsDairy Analysis & Instrumental Methods3 questionsDairy Colloids: Emulsions, Foams & Gels10 questionsMicrobiology of Raw & Market Milk2 questionsStarter Cultures & Lactic Acid Bacteria2 questionsDairy Pathogens, Toxins & Microbial Risk8 questionsProbiotics, Prebiotics & Functional Dairy Foods2 questionsMicrobiological Quality Assurance & Rapid Methods15 questionsFermentation Technology & Dairy Biotechnology29 questionsMarket Milk Processing12 questionsCheese Science & Technology10 questionsFermented Milks Technology8 questionsIce Cream & Frozen Dairy Desserts7 questionsConcentrated & Dried Dairy Products11 questionsInfant Formula & Nutritional Dairy Products2 questionsMembrane Processing & Dairy Ingredients1 questionsEmerging & Non-thermal Dairy Processing4 questionsDairy Analogues, Plant-based Alternatives & Composite Dairy Foods56 questionsDairy Packaging5 questionsRheology & Texture of Dairy Foods10 questionsFluid Flow, Thermodynamics & Heat Transfer in Dairy Plants49 questionsDairy Processing Equipment4 questionsEvaporation & Drying in Dairy Plants10 questionsDairy Refrigeration & Cold Chain2 questionsDairy Plant Utilities & Energy Management14 questionsCleaning-in-Place, Sanitation & Hygienic Design6 questionsDairy Effluent Treatment & Environmental Management11 questionsDairy Food Safety Management Systems7 questions

Five practice questions, worked

Original questions written to this exam's published syllabus and pattern. Not past papers.

1. For matrices A (3 by 2) and B (2 by 4), which statement is correct?

  1. Both AB and BA exist, and both are 3 by 4 matrices
  2. AB exists and is 3 by 4, while BA does not exist
  3. AB does not exist because A has fewer columns than rows
  4. BA exists and is 2 by 2, while AB does not exist
Answer and working

B. AB exists and is 3 by 4, while BA does not exist

A product needs columns of the first equal to rows of the second: A has 2 columns and B has 2 rows, so AB is 3 by 4. For BA, B has 4 columns but A has 3 rows, so BA is undefined.

Mathematics & Statistics for Dairy Science · Matrices and linear equations

2. An acetate buffer contains 0.10 mol/L acetic acid (pKa 4.76) and 0.20 mol/L sodium acetate. What is its pH?

  1. 5.06
  2. 4.46
  3. 4.76
  4. 9.52
Answer and working

A. 5.06

Henderson–Hasselbalch: pH = 4.76 + log(0.20/0.10) = 4.76 + 0.30 = 5.06. Inverting the ratio gives 4.46.

Biochemistry for Dairy Science · Water, pH and buffers

3. Koch's postulates require that the suspected organism be:

  1. Seen under the microscope in at least half of all the cases of the disease studied
  2. Isolated in pure culture and shown to reproduce the disease in a healthy host
  3. Able to grow on gelatin at body temperature without liquefying it
  4. Killed by pasteurisation at 63 °C for 30 minutes in every case
Answer and working

B. Isolated in pure culture and shown to reproduce the disease in a healthy host

The postulates: present in every case, isolated in pure culture, reproduces the disease in a healthy host, and re-isolated from it.

General Microbiology · History and scope of microbiology

4. Using Atwater factors, what is the energy of 100 mL of milk with 3.3 g protein, 3.6 g fat and 4.8 g lactose?

  1. 46.8 kcal
  2. 105.3 kcal
  3. 70.8 kcal
  4. 64.8 kcal
Answer and working

D. 64.8 kcal

3.3 × 4 + 3.6 × 9 + 4.8 × 4 = 13.2 + 32.4 + 19.2 = 64.8 kcal (about 270 kJ). Using 4 kcal/g for everything gives 46.8.

Human Nutrition & Dairy in the Diet · Macronutrients and energy requirements

5. In the propagation stage of auto-oxidation, a peroxyl radical:

  1. Is formed directly from a saturated fatty acid without oxygen
  2. Combines with another radical to form a stable non-radical product that ends the reaction chain
  3. Reacts with an antioxidant to stop the chain
  4. Removes hydrogen from another fatty acid, forming a hydroperoxide and a new lipid radical
Answer and working

D. Removes hydrogen from another fatty acid, forming a hydroperoxide and a new lipid radical

ROO• + RH -> ROOH + R• is propagation; radical combination is termination; reaction with antioxidants is chain-breaking inhibition.

Milk Lipids · Auto-oxidation: mechanism, factors and measurement

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