Biotechnology NEET Previous Year Questions with Answers & Analysis (2021–2025)

Biotechnology NEET PYQs: Important Chapters

Biotechnology is an important unit in NEET, and questions from important concepts are often repeated from previous years. Focusing on high-yield chapters can help students score well and save time during the exam. There are two important chapters under the biotechnology unit that every NEET aspirant must prepare well:

Chapter – Principles and Processes of Biotechnology

This chapter focusses on biotech principles such as genetic and bioprocess engineering. It also covers the tools and processes used in recombinant DNA technology.

Key Concepts to Focus

• Tools of Recombinant DNA Technology: Learn the roles of restriction enzymes, ligases, and vectors like plasmids and bacteriophages. Understand how each tool works to introduce a foreign gene into host organisms.

• Processes: Isolation of DNA, cutting and joining, inserting into a host, and cloning vectors.

• Bioreactors and Downstream Processing: Understand bioreactor design and working principle.

High-Weightage Topics for NEET 2026

• Mechanism and recognition site of restriction endonucleases (EcoRi, Hind III)

• pBR322 plasmid diagram-based questions

• Steps of rDNA technology

• Agrobacterium and Ti-Plasmid play important roles in gene transfer.

• Bioreactors are used to produce industrial products such as insulin.

Chapter 2 – Biotechnology and Its Applications

This chapter includes the applications of biotechnology in the fields of agriculture and medicine. It includes various products that are made with the help of rDNA technology. These products are useful for human health and sustainable agriculture. It also discusses the formation of transgenic animals and the ethical issues related to them.

Key Concepts to Focus

• Agricultural Applications: Bt crops, RNA interference, transgenic plants

• Medical Applications: Insulin production, gene therapy, techniques like PCR, ELISA

• Transgenic Animals: Examples and their application in various fields

• Ethical Issues: Biopiracy, biosafety, patents laws

High-Weightage Topics for NEET 2026

• Mechanism of Bt toxin and its production in Bacillus thuringiensis

• Steps in insulin synthesis

• Principles of PCR and ELISA

• Examples of Gene therapy (ADA deficiency)

• Biosafety levels

Biotechnology NEET Weightage Analysis (2021–2025)

The table given below gives NEET weightage analysis of questions from the two chapters of the unit Biotechnology from 2021 to 2025:

From the above table, it can be observed that on average, there are 8-9 questions from the Biotechnology unit every year, accounting for approximately 32-36 marks. This contributes to a significant 9.4% of the total NEET biology syllabus, showing its importance for the students who aim to score good marks.

How to Prepare Biotechnology for NEET 2026?

The unit of Biotechnology is quite scoring and easy if proper steps are followed. Here is a list of smart NEET preparation tips that students can follow to have a clear understanding of the unit.

Thorough NCERT Reading

Every NEET question comes directly or indirectly from the NCERT lines or diagrams. As a result, it is critical to begin by reading the NCERT textbook line by line and highlighting the most important points and definitions.

Concept Maps and Flowcharts

Concept maps and flowcharts are very helpful in learning the steps of a process. For example, steps of recombinant DNA technology, PCR, ELISA and insulin synthesis.

Mnemonics

Mnemonics make learning easy and fun. Processes that include several steps can be learned in minutes, for example, the steps of rDNA technology or PCR.

Solving PYQs and Concept-Based MCQs

Many of the MCQs in biotechnology are conceptual in nature. Therefore, it becomes essential to practice the NEET MCQs. Mastering PYQs ensures high accuracy and boosts confidence during the exam.

Biotechnology NEET Previous Year Questions

The unit "Biotechnology" poses a variety of questions, including match the following, step arrangement in order, assertion and reasoning, and diagram-based questions. Some of the most frequently asked questions are given below:

Q1. During the purification process for recombinant DNA technology, the addition of chilled ethanol precipitates out:

Options:

1. RNA

2. DNA

3. Histones

4. Polysaccharides

Explanation:

The purified DNA, after treatment with various enzymes, precipitates out after the addition of chilled ethanol. The process is known as DNA spooling. This process involves the careful winding of precipitated DNA around a glass rod or a comparable instrument, resulting in a structure that resembles a thread. This method is frequently used in molecular biology laboratories to isolate and gather DNA following extraction, facilitating both the visualisation and manipulation of the genetic material.

Hence, the correct answer is option 2) DNA.

Q2. The blue and white selectable markers have been developed, which differentiate recombinant colonies from non-recombinant colonies based on their ability to produce colour in the presence of a chromogenic substrate.

Given below are two statements about this method:
Statement I: The blue coloured colonies have a DNA insert in the plasmid, and they are identified as recombinant colonies.
Statement II: The colonies without blue colour have a DNA insert in the plasmid and are identified as recombinant colonies.

In light of the above statements, choose the most appropriate answer from the options given below:

Options:

1. Statement I is incorrect, but Statement II is correct.

2. Both Statement I and Statement II are correct.

3. Both Statement I and Statement II are incorrect.

4. Statement I is correct, but Statement II is incorrect.

Explanation:

In blue-white screening, a chromogenic substrate such as X-gal is employed. When the lacZ gene is unbroken (no insert of foreign DNA), the enzyme β-galactosidase is formed, and the colonies become blue and non-recombinant. When foreign DNA is added to the lacZ gene, it is broken, and the enzyme is not formed. The colonies are white, a sign of recombinant bacteria. Thus, Statement I is false: blue colonies are not recombinant. Statement II is true: white colonies are recombinant because they have the DNA insert.

Hence, the correct answer is Option 1) Statement I is incorrect, but Statement II is correct.

Q3. Which of the following enzyme(s) are NOT essential for gene cloning?

A. Restriction enzymes

B. DNA ligase

C. DNA mutase

D. DNA recombinase

E. DNA polymerase

Choose the correct answer from the options given below:

Options:

1. B and C only

2. C and D only

3. A and B only

4. D and E only

Explanation:

A. Restriction enzymes: These are valuable tools of gene cloning. They work like molecular scissors and cleave DNA at a defined sequence to form fragments that are introduced into vectors.

B. DNA ligase: This is also an important component in gene cloning. It connects the DNA fragment with vector DNA by making the sugar-phosphate backbone, and thus produces a stable recombinant DNA molecule.

C. DNA mutase: These are not needed in gene cloning. DNA mutases are the enzymes that make mutations in DNA, which is not a part of the gene cloning process.

D. DNA recombinase: This enzyme helps in the process of recombination between strands of DNA, which is used in advanced genetic engineering techniques but is not needed in gene cloning.

E. DNA polymerase: Not always, but this tool is often used in PCR to increase the amount of DNA before cloning.

DNA mutase and DNA recombinase are not required in the process of gene cloning.

Hence, the correct answer is option (2) C and D only.

Q4. Which of the following is not a desirable feature of a cloning vector?

Options:

1. Presence of a maker gene

2. Presence of a single restriction enzyme site

3. Presence of two or more recognition sites

4. Presence of the origin of replication

Explanation:

An ideal cloning vector would have a single recognition site for each restriction enzyme, preventing vector fragmentation due to the presence of multiple sites for the same enzyme, thereby reducing overall cloning efficiency. The above design allows for the efficient insertion of foreign DNA at the desired location without unwanted cleavage, allowing for successful ligation and propagation of the recombinant DNA in host cells in order to carry out a cloning experiment.

Hence, the correct answer is Option (3) - Presence of two or more recognition sites.

Q5. Which one of the following techniques does not serve the purpose of early diagnosis of a disease for its early treatment?

Options:

1. Recombinant DNA Technology

2. Serum and Urine analysis

3. Polymerase Chain Reaction (PCR) technique

4. Enzyme-Linked Immunosorbent Assay (ELISA) technique

Explanation:

Serum and urine analysis are useful diagnostic techniques, but they do not specifically serve the purpose of early diagnosis of a disease for its early treatment. Serum analysis involves testing the blood serum for various markers, such as antibodies or specific substances, to detect the presence of a disease or assess its progression. Urine analysis involves examining urine for abnormalities that may indicate certain diseases or conditions.

Hence, the correct answer is Option 2) - Serum and Urine Analysis.