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Q1. Enzyme required for polymerase chain reaction (PCR) is:

• RNA polymerase
• Ribonuclease
• Taq polymerase
• Endonuclease

Solution

One of the basic requirements of PCR is the functionality of enzymes at high temperature. A stable DNA polymerase, usually Taq polymerase which is stable at more than 90⁰C is used for the synthesis of new DNA molecules. 

Q2. Who among the following was awarded the Nobel Prize for the development of PCR technique?

• Herbert Boyer
• Har Gobind Khurana
• Kary Mullis
• Arthur Kornberg

Solution

Herbert W. Boyer discovered a method to coax bacteria into producing foreign proteins, thereby jump starting the field of genetic engineering. Har Gobind Khorana research helped to show how the order of nucleotides in nucleic acids, which carry the genetic code of the cell, control the cell’s synthesis of proteins. Arthur Kornberg was the first scientist to identify deoxyribonucleic acid (DNA) polymerase in the intestinal bacterium E coli. Kary Mullis received a Nobel Prize in Chemistry in 1993 for his invention of the Polymerase Chain Reaction (PCR).

Q3. Stanley and Herbert isolated the antibiotic-resistant gene from the plasmid of

• Saccharomyces cerevisiae
• Salmonella typhimurium
• Penicillium roqueforti
• Streptococcus thermophilus

Solution

Stanley and Herbert isolated the antibiotic-resistant gene from the plasmid of the bacterium Salmonella typhimurium.  

Q4. For transformation, micro-particles coated with DNA to be bombarded with gene gun are made up of :

• Silver or Platinum
• Platinum or Zinc
• Silicon or Platinum
• Gold or Tungsten

Solution

The technique of shooting foreign DNA into plant cells at a very high velocity is called biolistics. In this method, 1-2m gold or tungsten particles coated with DNA are shooted into the plant cells using a helium pressure particle gun device.

Q5. Plasmid is a:

• Fungus
• Plastid
• Part of plasma membrane
• Extra chromosomal DNA in bacterial cell

Solution

Plasmids are small, double stranded, closed circular symbiotic DNA molecules that occur naturally in bacteria outside the bacterial chromosome. They have the capability to self-replicate in the cytoplasm of the bacterial cell and are used as carriers for transferring a fragment of foreign DNA into a suitable host.

Q6. The polymerase chain reaction is a technique that

• is used for in vivo replication of DNA
• is used for in vivo synthesis of mRNA
• is used for in vitro synthesis of mRNA
• is used for in vitro replication of specific DNA sequence using thermostable DNA polymerase

Solution

Polymerase chain reaction is based on the principle that a DNA molecule, when subjected to high temperature, splits into two strands due to denaturation. These single stranded molecules are then converted to original double stranded molecules by synthesizing new strands in presence of enzyme DNA polymerase.

Q7. Which one of the following techniques made it possible to genetically engineer living organisms?

• recombinant DNA technique
• X-ray diffraction
• heavier isotope labelling
• hybridization

Solution

Recombinant DNA technology or genetic engineering refers to a series of methodologies in which the desired genes of DNA sequences of an organism are cut into fragments and then introduced into host cells with or without the help of carriers or vectors to alter its phenotype to suit human needs.

Q8. Restriction endonuclease

• Synthesizes DNA
• Cuts the DNA molecule randomly
• Cuts the DNA molecule at specific sites
• Restricts the synthesis of DNA inside the nucleus

Solution

Restriction endonucleases inspect the DNA molecule in search of specific recognition sequence. Once it gets its specific recognition sequence, it binds to the site and cuts each of the two strands of the double helix at specific points by hydrolyzing the phosphodiester bond.

Q9. The most recent definition for biotechnology was given by

• European Federation of Biotechnology
• Chinese Federation of Biotechnology
• Indian Federation of Biotechnology
• International Federation of Biotechnology

Solution

The most recent definition for biotechnology was given by the European Federation of Biotechnology. The definition states that biotechnology is the integrated use of biochemistry, microbiology and engineering sciences in order to achieve technological application of the capabilities of microorganisms, cultured tissue/cells and parts thereof.

Q10. Which one of the following is a case of wrong matching?

• Somatic hybridisation - Fusion of two diverse cells
• Vector DNA - Site for t-RNA synthesis
• Micropropagation - In vitro production of plants in large numbers
• Callus - Unorganised mass of cell produced in tissue culture

Solution

The vector DNA is used as a carrier for transferring a fragment of foreign DNA into a suitable host. The desired gene is introduced into the vector wherein recombinant DNA (r-DNA) is formed. The vector carrying r-DNA divides, thereby forming several copies of r-DNA.

Q11. The process of extension requires which of the following ions?

• Mg²⁺
• Mn²⁺
• Na²⁺
• Cl²⁻

Solution

The process of extension in PCR requires the presence of Taq DNA polymerase, deoxynucleoside triphosphate and Mg²⁺.

Q12. Agarose extracted from sea weeds is used in

• Spectrophotometry
• Tissue culture
• PCR
• Gel electrophoresis

Solution

Agarose is the most commonly used matrix in gel electrophoresis. It is a polysaccharide extracted from sea weeds. DNA fragments move towards the anode according to their molecular size through the agarose gel.

Q13. DNA fingerprinting can resolve:

• Identification of a person
• Paternity dispute
• Maternity dispute
• All of above

Solution

DNA fingerprinting is a technique employed to assist in the identification of individuals by their respective DNA profiles. It is used in parental testing and criminal investigation.

Q14. In the process of electroporation, the application of electric current causes

• Disintegration of the cell membrane
• An increase in the porosity of protoplasts
• Disintegration of the cell wall
• An increase in the charge on protoplasts

Solution

In the process of electroporation, the application of electric current increases the porosity of protoplasts. This causes the cell to easily take up the foreign DNA present in the outside of the cell.

Q15. Process used for amplication or multiplication of DNA for fingerprinting is:

• Polymerase chain reaction
• Nesslerisation
• Southern blotting
• Northern blotting

Solution

Polymerase chain reaction is a technique of synthesizing multiple copies of the desired gene (DNA) in vitro. Nesslerisation is the classical colorimetric method for ammonia determination. Southern blot is a method routinely used in molecular biology for detection of a specific DNA sequence in DNA samples. Southern blot analysis reveals information about DNA identity, size and abundance. Northern blot is a technique used in molecular biology research to study gene expression by detection of RNA in a sample. Northern blot analysis reveals information about RNA identity, size and abundance. 

Q16. Which enzyme is used to dissolve fungal cell walls?

• Lysozyme
• Cellulase
• Chitinase
• Hydrolase

Solution

The chief component of the fungal cell wall is chitin. Hence, chitinase is used for dissolving the fungal cell wall.

Q17. One of the key factors, which makes plasmid the vector in genetic engineering is that

• It is resistant to antibiotics.
• It is resistant to restriction enzymes.
• It has the ability to carry a foreign gene.
• It has the ability to cause infection in the host.

Solution

Plasmids are small, double stranded, closed circular symbiotic DNA molecules that occur naturally in bacteria outside the bacterial chromosome. They have the capability to self-replicate in the cytoplasm of the bacterial cell and are used as carriers for transferring a fragment of foreign DNA into a suitable host.

Q18. Gel electrophoresis is used for

• Construction of recombinant DNA by joining with cloning vectors
• Isolation of DNA molecules
• Cutting of DNA into fragments
• Separation of DNA fragments according to their size

Solution

Gel electrophoresis is a technique used for the separation of substances of different ionic properties. During electrophoresis, DNA fragments move towards the anode according to their molecular size through the agarose gel.

Q19. The bonds which are broken down during the denaturation step of PCR are

• Peptide bonds
• Hydrogen bonds
• Phosphodiester bonds
• Covalent bonds

Solution

In the denaturation step of PCR, the two strands of the DNA molecule are split apart. Because the two strands are held together by hydrogen bonds between the complementary nitrogen bases on each strand, hydrogen bonds are broken down during this step.

Q20. Humulin is a

• Carbohydrate
• Fat
• Hybridoma
• Protein

Solution

Humulin (human insulin and isophane suspension) is a human insulin suspension. Humulin is a purified protein derivative produced by recombinant DNA technology utilizing a non-pathogenic laboratory strain of Escherichia coli.

Q21. Who is regarded as the ‘father of genetic engineering’?

• Paul Berg
• Stanley Cohen
• Hamilton Smith
• Hohn

Solution

Paul Berg was the first to successfully introduce a gene (SV-40) into a bacterium with the help of a lambda phage, and hence, he is regarded as the ‘father of genetic engineering’.

Q22. Use of biology in industrial process and for improving quality of life is called:

• Biotechnology
• Microbiology
• Genetic engineering
• Eugenics

Solution

Use of biology in industrial process and for improving quality of life is called biotechnology. Microbiology is the study of microscopic organisms. Genetic engineering is the direct manipulation of an organism's genome using biotechnology. Eugenics is the belief and practice of improving the genetic quality of human population.

Q23. Two microbes found to be very useful in genetic engineering are

• Crown gall bacterium and Caenorhabditis elegans
• Escherichia coli and Agrobacterium tumefaciens
• Vibrio cholerae and a tailed bacteriophage
• Diplococcus sp. and Pseudomonas sp.

Solution

Escherichia coli possesses plasmid which encodes genes that may act as selectable markers in transformations. Agrobacterium tumefaciens possesses Ti plasmid that induces tumour formation. These have been used as vectors to transfer foreign genes of interest into the target animal and plant cells.

Q24. The ability of a cell to grow into a complete plant is called:

• Somaclonal variation
• Cellular totipotency
• Protoplasmic fusion
• Tissue culture

Solution

Cellular totipotency is the ability of a single cell to divide and produce all the differentiated cells in an organism. Somaclonal variation is the variation seen in plants that have been produced by plant tissue culture. Protoplast fusion is a type of genetic modification in plants by which two distinct species of plants are fused together to form a new hybrid plant with the characteristics of both. Tissue culture is a process that involves exposing plant tissue to a specific regimen of nutrients, hormones and light under sterile, in vitro conditions to produce many new plants, each of which is a clone of the original mother plant, over a very short period of time.

Q25. A bioreactor is:

• Fermentation tank
• Culture containing radioactive isotopes
• Culture for synthesis of new chemicals
• Hybridoma

Solution

Bioreactors are large vessels with a capacity of 100 to 1000 litres, which are used for biological conversion of raw materials into specific products. Each bioreactor has a cylindrical stirred tank to facilitate the mixing of contents. It has an agitator system to mix the contents properly, an oxygen delivery system to make availability of oxygen, a foam control system, a temperature control system, a pH control system and a sampling port to withdraw small volumes of the culture periodically.

Q26. Taq polymerase is isolated from

• Thermophilus aureus
• Thermus aquaticus
• Thermophilus aquaticus
• Thermus aureus

Solution

Taq DNA polymerase is isolated from the thermophilus bacteria Thermus aquaticus.

Q27. Who discovered recombinant DNA (rDNA) technology?

• Har Gobind Khorana
• James D. Watson
• Stanley Cohen and Herbert Boyer
• Walter Sutton and Avery

Solution

Herbert Boyer and Stanley Cohen combined their efforts in biotechnology to invent the rDNA technology method of cloning genetically engineered molecules in foreign cells. Har Gobind Khorana research helped to show how the order of nucleotides in nucleic acids, which carry the genetic code of the cell, control the cell’s synthesis of proteins. James D. Watson is best known as a co-discoverer of the structure of DNA in 1953 with Francis Crick. Walter Sutton and Avery proposed that chromosomes bear hereditary factors. 

Q28. The first restriction endonuclease was isolated by

• Arber, Nathan and Smith
• Paul Berg
• Annie Chang and Stanley Cohen
• Collins and Hohn

Solution

The first restriction endonuclease was isolated by Arber, Nathan and Smith from the bacterium Haemophilus parainfluenzae.

Q29. The temperature required for the process of annealing is carried out at a temperature of

• 30-50°C
• 30-80°C
• 20-40°C
• 40-60°C

Solution

In PCR, annealing is the second step. In this process, the denatured DNA strands are hybridised to the DNA primers. The step is carried out at 40-60°C.

Q30. Polymerase chain reaction is useful in

• DNA synthesis
• DNA amplification
• Protein synthesis
• Amino acid synthesis