Biotechnology Interview Questions & Answers

Biotechnology graduates are interviewed by pharma and biopharma companies, fermentation and enzyme plants, diagnostic labs, research institutes and agri-biotech firms. The panel wants to see clean laboratory thinking: aseptic technique, correct calculations, good documentation and an understanding of GMP. The 50 questions below cover the cell, the central dogma, enzymes, microbes, sterilisation, PCR and fermentation. Along with them this page explains how the rounds usually run, which topics to revise, two worked examples (a contamination investigation and a dilution calculation) and the mistakes that weaken a biotech fresher’s interview.

How a Biotechnology fresher interview usually runs

Technical round — cell biology, molecular biology, microbiology, biochemistry and bioprocess basics.
Lab and calculation round — solution preparation, dilutions, media preparation and interpreting results.
Quality and GMP round — documentation, cleanroom behaviour, deviations and data integrity.
HR round — shift work, lab safety attitude and willingness to learn instruments.

Revise these 8 topics first

Molecular biology: DNA, RNA, protein, central dogma, PCR and gel electrophoresis.
Microbiology: differences between bacteria, yeast, fungi and viruses, and Gram staining.
Sterilisation: autoclave conditions, filtration and the difference between sterilisation and disinfection.
Enzymes: enzyme kinetics, factors affecting activity and immobilisation.
Fermentation: batch, fed-batch and continuous modes, and the parts of a bioreactor.
Downstream processing: centrifugation, filtration and chromatography at a basic level.
Lab calculations: molarity, percent solutions and dilution (C1V1 = C2V2).
GMP and safety: aseptic technique, biosafety levels and documentation habits.

Showing the first 50 questions free. The complete 250-question bank is available as a PDF below.

Biotechnology — Q1 to Q50

Q1What is Biotechnology?

AnswerBiotechnology is the application of biological systems, organisms, cells, or biomolecules to develop useful products and processes. It combines biology with engineering, chemistry, and technology and is used in areas such as pharmaceuticals, agriculture, food, healthcare, and environmental management.

Q2What are the major applications of Biotechnology?

AnswerMajor applications include pharmaceutical production, vaccines, diagnostics, agricultural biotechnology, food processing, industrial enzymes, biofuels, environmental treatment, waste management, and development of genetically engineered products.

Q3What are the major branches of Biotechnology?

AnswerMajor branches include medical biotechnology, industrial biotechnology, agricultural biotechnology, environmental biotechnology, food biotechnology, marine biotechnology, and bioinformatics. Each branch applies biological knowledge to a specific industrial or scientific problem.

Q4What is the difference between Biotechnology and Biochemical Engineering?

AnswerBiotechnology focuses mainly on using biological systems and organisms to develop products or processes. Biochemical engineering focuses on designing, scaling, controlling, and optimizing the processes and equipment used to produce those biological products on an industrial scale.

Q5What is a cell?

AnswerA cell is the basic structural and functional unit of life. It contains various components that perform specific functions such as energy production, genetic information storage, protein synthesis, and transport of materials.

Q6What is the difference between prokaryotic and eukaryotic cells?

AnswerProkaryotic cells do not have a membrane-bound nucleus and generally have simpler internal structures. Eukaryotic cells have a well-defined nucleus and membrane-bound organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus.

Q7What is the function of the cell membrane?

AnswerThe cell membrane separates the cell from its surroundings and controls the movement of substances into and out of the cell. It also participates in cell signaling and helps maintain the internal environment of the cell.

Q8What is the function of the nucleus?

AnswerThe nucleus stores most of the genetic material in a eukaryotic cell and regulates many cellular activities. It plays an important role in DNA replication and the control of gene expression.

Q9What is DNA?

AnswerDNA, or deoxyribonucleic acid, is the primary genetic material in most organisms. It stores hereditary information in the form of nucleotide sequences that provide instructions for producing functional RNA and proteins.

Q10What is RNA?

AnswerRNA, or ribonucleic acid, is involved in transferring and expressing genetic information. Major types include messenger RNA, transfer RNA, and ribosomal RNA, which participate in protein synthesis and other cellular processes.

Q11What is a gene?

AnswerA gene is a specific sequence of DNA that contains information required to produce a functional product, usually a protein or functional RNA. Genes are fundamental units of heredity and influence biological characteristics.

Q12What is a chromosome?

AnswerA chromosome is a DNA-containing structure associated with proteins that organizes genetic material inside a cell. It carries many genes and helps ensure proper transmission of genetic information during cell division.

Q13What is the central dogma of molecular biology?

AnswerThe central dogma describes the general flow of genetic information from DNA to RNA and from RNA to protein. DNA is transcribed into RNA, and RNA is translated into a protein.

Q14What is DNA replication?

AnswerDNA replication is the process by which a cell makes a copy of its DNA before cell division. The process uses complementary base pairing so that each new DNA molecule contains one original strand and one newly synthesized strand.

Q15What is transcription?

AnswerTranscription is the process of producing RNA using a DNA template. An enzyme called RNA polymerase reads the relevant DNA sequence and synthesizes a complementary RNA molecule.

Q16What is translation?

AnswerTranslation is the process by which ribosomes use the information present in messenger RNA to synthesize a protein. Transfer RNA brings appropriate amino acids according to the sequence specified by the mRNA.

Q17What are proteins?

AnswerProteins are biological macromolecules made up of amino acids joined by peptide bonds. They perform many functions, including catalysis, transport, structural support, signaling, and regulation of cellular processes.

Q18What are amino acids?

AnswerAmino acids are the basic building blocks of proteins. Different amino acids combine in specific sequences to form proteins, and their sequence determines the structure and function of the resulting protein.

Q19What is an enzyme?

AnswerAn enzyme is a biological catalyst that increases the rate of a biochemical reaction without being consumed in the reaction. Most enzymes are proteins, although some RNA molecules can also have catalytic activity.

Q20What is an active site of an enzyme?

AnswerThe active site is the specific region of an enzyme where the substrate binds and the chemical reaction takes place. Its structure and chemical properties determine the enzyme's specificity.

Q21What is enzyme specificity?

AnswerEnzyme specificity is the ability of an enzyme to recognize and act on a particular substrate or a specific group of related substrates. This occurs because the active site has suitable structural and chemical characteristics.

Q22How does temperature affect enzyme activity?

AnswerAs temperature increases, enzyme activity generally increases up to an optimum temperature because molecular movement becomes faster. Beyond the optimum, excessive heat can disrupt the enzyme's structure and reduce its activity.

Q23How does pH affect enzyme activity?

AnswerEach enzyme generally has an optimum pH range at which it functions most effectively. Significant deviation from this range can alter the enzyme's structure or active site and reduce its catalytic activity.

Q24What is a microorganism?

AnswerA microorganism is an organism or biological entity that is generally too small to be seen clearly with the unaided eye. Examples include bacteria, yeasts, many fungi, protozoa, and certain microscopic algae.

Q25What is the difference between bacteria, yeast, fungi, and viruses?

AnswerBacteria are generally single-celled prokaryotic organisms. Yeasts are unicellular fungi, while molds are multicellular fungi. Viruses are acellular infectious agents that require a suitable host cell for replication.

Q26What is microbial growth?

AnswerMicrobial growth refers to an increase in the number of microbial cells in a population. Under suitable conditions, microorganisms reproduce and pass through phases such as lag, exponential, stationary, and decline phases.

Q27What is culture media?

AnswerCulture media are nutrient-containing materials used to support the growth of microorganisms or cells under controlled conditions. They can be formulated to provide specific nutrients and environmental conditions required by the target organism.

Q28What is aseptic technique?

AnswerAseptic technique consists of practices used to prevent unwanted microorganisms from entering a biological culture, sample, or sterile environment. It is essential for maintaining culture purity and obtaining reliable experimental or production results.

Q29What is sterilization?

AnswerSterilization is a process used to eliminate all viable forms of microorganisms from a material or equipment to the required level of sterility. Methods include heat, filtration, radiation, and appropriate chemical processes.

Q30What is an autoclave?

AnswerAn autoclave is a sterilization equipment that uses saturated steam under controlled pressure and temperature to sterilize suitable materials. It is widely used in laboratories and biotechnology facilities for sterilizing media, glassware, and other compatible items.

Q31What is the difference between sterilization and disinfection?

AnswerSterilization aims to eliminate all viable microorganisms, whereas disinfection reduces or eliminates harmful microorganisms on surfaces or objects but does not necessarily achieve complete sterility.

Q32What is recombinant DNA technology?

AnswerRecombinant DNA technology involves combining DNA sequences from different sources to create a new DNA molecule. It is widely used in biotechnology for research and for producing useful biological products such as recombinant proteins.

Q33What is a plasmid?

AnswerA plasmid is a small, usually circular DNA molecule found mainly in bacteria that can replicate independently of the bacterial chromosome. In biotechnology, plasmids can serve as vectors for carrying selected genetic material.

Q34What is a vector in genetic engineering?

AnswerA vector is a DNA carrier used to introduce genetic material into a suitable host cell. Depending on the application, vectors may include plasmids or other engineered genetic delivery systems.

Q35What are restriction enzymes?

AnswerRestriction enzymes are enzymes that recognize specific DNA sequences and cut DNA at or near those sequences. They are important tools in recombinant DNA technology and molecular biology.

Q36What is DNA ligase?

AnswerDNA ligase is an enzyme that joins DNA fragments by forming bonds in the DNA backbone. It is commonly used in molecular biology when DNA fragments need to be joined together.

Q37What is PCR?

AnswerPCR, or Polymerase Chain Reaction, is a molecular biology technique used to amplify a selected DNA region. It produces many copies of a target DNA sequence through repeated cycles of controlled DNA synthesis.

Q38What is gel electrophoresis?

AnswerGel electrophoresis is a laboratory technique used to separate DNA, RNA, or proteins based on properties such as size and electrical charge. The separated components can then be visualized and analyzed.

Q39What is genetic engineering?

AnswerGenetic engineering is the deliberate modification or manipulation of an organism's genetic material using molecular biology techniques. It can be used for research, development of biological products, and improvement of selected biological characteristics.

Q40What is fermentation in Biotechnology?

AnswerIn biotechnology, fermentation refers to the controlled cultivation of microorganisms or cells to produce a desired product. Products may include enzymes, organic acids, antibiotics, vaccines, biofuels, and other bioproducts.

Q41What is a bioreactor?

AnswerA bioreactor is a controlled vessel in which biological reactions or cell cultivation are carried out under defined conditions. Important parameters can include temperature, pH, dissolved oxygen, agitation, aeration, and nutrient availability.

Q42What is an inoculum?

AnswerAn inoculum is a prepared culture introduced into a production medium or bioreactor to initiate growth. A suitable inoculum should generally be healthy, viable, and appropriate for the intended process.

Q43What is the difference between batch, fed-batch, and continuous fermentation?

AnswerIn batch fermentation, nutrients are initially added and the process runs without continuous feeding of fresh medium. In fed-batch fermentation, nutrients are added during the process according to a controlled feeding strategy. In continuous fermentation, fresh medium is continuously supplied while culture broth is continuously removed under controlled conditions.

Q44Why are pH, temperature, and dissolved oxygen controlled in a bioreactor?

AnswerThese parameters directly influence cell growth, metabolism, and product formation. Maintaining them within the required operating range helps achieve consistent biological performance, product quality, and process productivity.

Q45What is upstream processing?

AnswerUpstream processing includes activities involved in preparing and cultivating the biological system before product recovery. It can include media preparation, culture development, inoculum preparation, sterilization, and bioreactor operation.

Q46What is downstream processing?

AnswerDownstream processing includes the recovery, separation, purification, concentration, and formulation of the desired product after cultivation. Common operations include filtration, centrifugation, chromatography, and other purification methods.

Q47What would you check if a microbial culture suddenly shows contamination?

AnswerI would first isolate the affected culture and follow the applicable laboratory SOP. I would check aseptic practices, media and equipment status, handling steps, environmental conditions, and possible sources of contamination. I would document the observation and inform the responsible supervisor rather than continuing with a compromised culture.

Q48What would you do if cell growth is much lower than expected in a bioprocess?

AnswerI would systematically check critical process parameters such as temperature, pH, dissolved oxygen, nutrient availability, inoculum condition, agitation, and possible contamination. I would compare the actual values with the approved process limits, review the batch records, and investigate the deviation before making any process change.

Q49What is GMP and why is it important in Biotechnology?

AnswerGMP, or Good Manufacturing Practice, is a quality system framework that helps ensure products are consistently produced and controlled according to defined quality standards. It emphasizes controlled processes, documentation, traceability, trained personnel, equipment qualification, and contamination control.

Q50What skills should a Biotechnology fresher develop for an industrial career?

AnswerA Biotechnology fresher should develop strong fundamentals in microbiology, molecular biology, biochemistry, cell biology, and bioprocessing. In addition, practical knowledge of aseptic techniques, laboratory equipment, documentation, GMP principles, data analysis, basic instrumentation, and problem-solving is valuable for entering the biotechnology industry.

Worked examples interviewers like

Example 1: “A fermentation batch is contaminated. How will you investigate?”

Confirm the contamination with microscopy or Gram staining and plating a sample.
Review the sterilisation record of the vessel and medium (for example, autoclave at 121 °C for the validated time).
Check seals, valves, sampling points and the air filter integrity.
Review the inoculum purity and the aseptic technique used during inoculation and sampling.
Record a deviation, find the root cause and put in a corrective action before the next batch.

Example 2: “Prepare 10 mL of a 100 µg/mL solution from a 10 mg/mL stock.”

Convert: 100 µg/mL = 0.1 mg/mL.
Use C1V1 = C2V2: 10 × V1 = 0.1 × 10, so V1 = 0.1 mL.
Take 0.1 mL of stock and add 9.9 mL of diluent to make 10 mL.

Always say the units out loud while calculating. Unit mistakes are the commonest lab error.

Common mistakes that cost candidates the job

Confusing sterilisation with disinfection.
Skipping calculations or unit conversions in the lab round.
Having no clear idea of GMP and documentation, which pharma interviews stress.
Memorising pathways but being unable to explain one practical technique from the lab.
Not asking about safety when handling microorganisms or chemicals.

Frequently asked questions

Which industries hire B.Tech biotechnology freshers?

Pharma and biopharma, vaccine and diagnostics companies, enzyme and fermentation plants, food and agri-biotech, and research or testing labs.

Should I do a higher degree?

Research roles often prefer an M.Tech or M.Sc and a PhD. Industry roles in production and quality welcome B.Tech with good lab skills.

What helps in the interview?

An internship, a lab project you can explain step by step and clear knowledge of GMP basics.

Keep preparing

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