Biotechnology MCQ Quiz - Objective Question with Answer for Biotechnology - Download Free PDF

The Correct answer is proteins synthesised by transgene in host cell by rDNA technology.

Key Points

• Recombinant proteins are synthesized using recombinant DNA (rDNA) technology, which involves inserting a transgene into a host cell.
• This process enables the production of specific proteins by leveraging the host organism’s cellular machinery.
• These proteins have a wide range of applications, including therapeutics, diagnostics, and industrial enzymes.
• Host cells used in this technology can vary and include bacteria, yeast, insect, and mammalian cells, depending on the requirements.
• Examples of recombinant proteins include insulin, growth hormones, monoclonal antibodies, and vaccines.
• The process involves isolation of the gene of interest, insertion into a vector, transformation into a host cell, and expression of the protein.
• Recombinant proteins are critical in the production of biosimilars and biopharmaceuticals for treating diseases like diabetes, cancer, and autoimmune disorders.

 Additional Information

• Proteins synthesised in animal models
  • These proteins are naturally produced in animal models for research purposes, such as studying the effects of certain genes or drugs.
  • They are not produced using recombinant DNA technology but are derived from the animal's native cellular processes.
• Natural proteins found in bacteria
  • These are proteins that are naturally synthesized by bacteria as part of their metabolic processes.
  • Examples include enzymes like DNA polymerase and proteins involved in bacterial growth and replication.
  • These are not recombinant proteins as they are not produced through genetic modification.
• Proteins synthesised in mutated cell lines
  • These proteins are produced in genetically altered cell lines to study disease mechanisms or drug effects.
  • However, this does not necessarily involve the use of rDNA technology and transgenes.

The correct answer is Tissue Culture.

Key Points

• Tissue culture is a technique used to grow plants under sterile conditions on a nutrient culture medium.
• This method is used to produce clones of a plant in a method known as micropropagation.
• Tissue culture can be used to propagate plants that produce seeds which do not readily germinate.
• It is employed in conserving rare or endangered plant species and has applications in both research and commercial sectors.
• The process involves the use of small pieces of plant tissue (explants) which are cultured in a controlled, sterile environment.

Additional Information

• Transformation
  • This is a process by which genetic material is introduced into a cell, resulting in a change in the cell's properties.
  • It is widely used in genetic engineering to create genetically modified organisms (GMOs).
• Plant Breeding
  • This is the science of changing the traits of plants in order to produce desired characteristics.
  • It is used to develop new plant varieties with improved yields, disease resistance, and drought tolerance.
• DNA Replication
  • This is the process by which a cell duplicates its DNA, ensuring that each new cell receives an exact copy of the parent cell's genetic material.
  • It is a fundamental process in cell division and is essential for the growth and reproduction of all living organisms.

Key Points

• Agrobacterium tumefaciens is a bacterium that is used to obtain the Ti plasmid.
• This bacteria is a pathogen for several dicot plants.
• The Ti plasmid is known as the tumor-inducing plasmid as it is responsible for converting normal cells into tumor cells in the plant.
• The bacteria delivers the pathogenic DNA called T-DNA with the help of this Ti-plasmid.
• The T-DNA induces the formation of tumor or crown gall, which then secretes the chemicals required by the pathogen.
• This Ti-plasmid has been modified to be a non-pathogenic cloning vector that can efficiently deliver our desired gene fragment.
• These plasmid vectors were also used for RNA interference (RNAi), to prevent infestation of tobacco roots by the nematode Meloidegyne incognita.

Additional Information

• Bt-toxin -
  • It is obtained from the bacterium Bacillus thuringiensis.
  • It is toxic for certain insects that attack plants.
  • The gene for this toxin is called cry gene, which can be genetically introduced into a host plant to get resistance from a particular insect pest.
• Taq polymerase -
  • It is a thermostable DNA polymerase that is used for repeated amplification in PCR.
  • This enzyme remains active even in high temperatures because it is obtained from the bacteria Thermus aquaticus, which survives in extreme heat conditions like hot springs
• pBR322 -
  • It is a plasmid that is widely used as E. coli cloning vector.
  • It contains ampicillin and tetracycline resistance genes as selectable markers.

Concept:

• Polymerase chain reaction (PCR) is a technique for making copies of specific DNA molecules. It was developed by scientist Kary Mullis.
• A short fragment of DNA can be amplified using primers and enzymatic reaction.

Important Points

• PCR takes place in 3 steps-Denaturation, Annealing, and extension.
• The first step is denaturation. It is a process of separation of two strands of DNA at a high temperature of 94°C. It breaks the hydrogen bonds between two strands of DNA.
• The second step is annealing. It involves the binding of two short primers for DNA synthesis. Primers are single-stranded short sequences of DNA and RNA.
• The third step is an extension. For this step, there is a need for a Taq polymerase enzyme that adds nucleotides to the 3’ end of primers. The temperature is maintained at 72-80°C.
• ​These steps are repeated in cycles such that we get about a billion copies of the DNA in 30 cycles.

Additional Information 

• A thermostable DNA polymerase is used for repeated amplification.
• This is achieved by Taq polymerase which is obtained from Thermus aquaticus.
• This enzyme remains active even in high temperatures because the bacteria from which it is extracted survive in extreme heat conditions like hot springs.

​So, the correct answer is option 3.

Correct Answer: 1)

Solution:

Concept: 

• Golden Rice is a crop that is modified genetically and biofortified.
• Biofortified crops have more nutritional value.
• Golden rice is modified in such a way that it can produce beta-carotene.
• When these rice are metabolized by the human body, the beta-carotene present in them is converted to vitamin A.
• These rice were modified by the gene from daffodil (Narcissus pseudonarcissus).
• Normal rice crop does not contain beta-carotene.

Explanation:

Option 1: It is vitamin A enriched, with a gene from daffodil– CORRECT

• Golden rice is rich in beta-carotene which on digesting is converted to vitamin A.
• And the gene is used from daffodil.
• Hence, this option is correct.

Option 2: It is pest resistant, with a gene from Bacillus thuringiensis– INCORRECT

• Pest resistant gene from Bacillus thrungenesis is used in the case of Bt cotton.
• In which the cotton plant is modified to be pest resistant.
• Hence this option is incorrect.

Option 3: It is drought tolerant, developed using Agrobacterium vector– INCORRECT

• Agrobacterium is the vector used in the modification of golden rice.
• But the gene inserted does not make the crop drought tolerant.
• Hence this option is incorrect.

Option 4: It has yellow grains, because of a gene introduced from a primitive variety of rice– INCORRECT

• It is correct that the color of the golden rice grain is yellow and that's why the term golden rice is used.
• But the gene used for modification is from daffodil not from a primitive variety of rice.
• Hence this option is incorrect.

So, the correct answer is option 1). 

Concept-

• Restriction enzymes belong to a larger class of enzymes called nucleases.
• Restriction enzymes are used to break DNA molecules.
• Restriction enzymes are of three types- Exonuclease, endonuclease, and restriction endonuclease.
  • Exonuclease- They cut off nucleotides from 5' or 3' ends of DNA molecule.
  • Endonuclease- They break DNA duplex at any point except the end.
  • Restriction endonuclease- They cleave DNA duplex at specific points.

Explanation-

• Restriction endonuclease was found by Arber.
• They act as "molecular scissors".
• They recognize the base sequence at palindrome sites in the DNA duplex and cut its strands.
• Hind II, whose functioning depended on a specific DNA nucleotide sequence was isolated.
• It was found that Hind II always cut DNA molecules at a particular point by recognizing a specific sequence of six base pairs.
• This specific base sequence is known as the recognition sequence for Hind II.

The first restriction endonuclease-Hind II.

Additional Information

Name	Recognition sequence	Source
EcoRI		Escherichia coli-containing drug resistance plasmid RI.
Bam I		Bacillus amyloliquefaciens
Hae III		Haemophilus aegyptius
Hind III		Haemophilus influenzae

Both statements are correct.

Key Points

• Among many, the two core techniques that enabled the birth of modern biotechnology are :
  • Genetic engineering: Techniques to alter the chemistry of genetic material (DNA and RNA), to introduce these into host organisms and thus change the phenotype of the host organism.
    • The techniques of genetic engineering include the creation of recombinant DNA, the use of gene cloning, and gene transfer
  • Maintenance of sterile (microbial contamination-free) ambiance in chemical engineering processes to enable the growth of only the desired microbe/eukaryotic cell in large quantities for the manufacture of biotechnological products like antibiotics, vaccines, enzymes, etc.

Concept-

• A transgenic crop is a crop whose genes have been altered by manipulation. This crop is known as genetically modified crops (GM crops).
• GM plants can reduce reliance on chemical pesticides (pest-resistance crops).
• Transgenic means that one or more DNA sequences from another r species have been introduced by artificial means.
• Transgenic plants can be made by introducing foreign DNA into a variety of different tissues.
• It is a plant that has a novel combination of genetic material obtained through biotechnology that adds a new quality to the parent crop like herbicide-tolerance. 

Key Points

The first genetically modified plant was produced in 1982, an antibiotic-resistant tobacco plant.

• A nematode Meloidogyne incognita infects the roots of tobacco plants and causes a great reduction in yield.
• A novel strategy was adopted to prevent this infestation which was based on the process of RNA interference (RNAi).
• RNAi takes place in all eukaryotic organisms as a method of cellular defense.
• This method involves silencing of a specific mRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA (silencing).
• The source of this complementary RNA could be from infection by viruses having RNA genomes or mobile genetic elements (transposons) that replicate via an RNA intermediate.

Additional Information

Bt Cotton- 

• Some strains of Bt produce proteins that kill certain insects such as lepidopterans, coleopterans, and dipterans.
• Bt forms protein crystals during a particular phase of their growth.
• These crystals contain a toxic insecticidal protein.

Golden rice-

• Rice is a staple food in many countries.
• By inserting two genes from daffodil and one gene from a bacterial species into the rice.
• Scientists produced rice capable of synthesizing β - carotene.

Tomato-

• Transgenic variety of Tomato - Flavr Savr.
• Due to inhibition of polygalacturonase enzyme which degrades pectin.
• So tomato variety remains fresh.

The correct answer is Recombinant DNA technology.

Important Points

Recombinant DNA technology:

• This technique is mainly used to change the phenotype of an organism (host) when a genetically altered vector is introduced and integrated into the genome of the organism.
• So, this process involves the introduction of a foreign piece of DNA structure into the genome which contains our gene of interest. This gene that is introduced is the recombinant gene. So, option 2 is correct.

​Additional Information

• Blotting technique: Blots are techniques for transferring DNA, RNA, and proteins onto a carrier so they can be separated, and often follows the use of gel electrophoresis. The Southern blot is used for transferring DNA, the Northern blot for RNA, and the western blot for PROTEIN.
• Gene cloning is a traditional method or technique used in molecular genetics to make DNA copies.
• Polymerase chain reaction, or PCR, is a technique to make many copies of a specific DNA region in vitro (in a test tube rather than an organism).

Concept-

• In genetic engineering, we can break the DNA molecule at two desired places with the help of endonuclease.
• And then insert it in another DNA molecule at the desired place.
• The new DNA molecule is called recombinant DNA.
• Genetic engineering can be used to improve the quality of human life.

Explanation-

• The first genetically engineered insulin obtained by recombinant DNA technique with the help of E-Coli was developed by the American firm, Eli-Lilly on 5 July 1983.
• Insulin is used for diabetes.
• Insulin consists of two short polypeptide chains: chain A and chain B, that are linked together by disulfide bridges.
• Eli Lilly an American company prepared two DNA sequences corresponding to A and B, chains of human insulin, and introduced them in plasmids of E. coli to produce insulin chains.
• Chains A and B were produced separately, extracted, and combined by creating disulfide bonds to form human insulin. 

Therefore the first Human hormone product by Recombinant DNA technology is insulin.

Additional InformationEstrogen

• Estrogens produce wide-ranging actions such as stimulation of growth and activities of female secondary sex organs, development of growing ovarian follicles, the appearance of female secondary sex characters (e.g., the high pitch of voice, etc.), mammary gland development.
• Estrogens also regulate female sexual behavior.

Progesterone

• Progesterone supports a pregnancy.
• Progesterone also acts on the mammary glands and stimulates the formation of alveoli (sac-like structures which store milk) and milk secretion. 

Thyroxine

• Thyroxine is the hormone secreted by the thyroid gland.

The correct answer is B & C.

Explanation:

The production of an exact copy of a cell, a part of the animal or the complete animal through asexual reproduction is called cloning.

A. It is possible only in animals. (false)

• Human cloning is the creation of a genetically identical copy (or clone) of a human. 
• The term is generally used to refer to artificial human cloning, which is the reproduction of human cells and tissue. It does not refer to the natural conception and delivery of identical twins.

B. It results in exact replication of a cell, a living part of an organism. (true)

• A clone is genetically identical to the parent organism.
• Since only one parent is involved in asexual reproduction, the offspring produced is genetically identical to the parent cell. 
• As they are exact copies of their parents, offspring is said to be a clone. 
• This type of reproduction can be seen in prokaryotic microbes and even in a few eukaryotic single-celled and multi-celled entities. 

C. It results in a large number of off-springs". (true)

• A single individual can give rise to offspring asexually and a large number of offspring can hence be quickly produced.

The correct answer is Option 4, i.e. 1, 2 and 3.

Key Points

• Vectors used at present, are engineered in such a way that they help easy linking of foreign DNA and selection of recombinants from non-recombinants.
• The following are the features that are required to facilitate cloning into a vector.

1. Origin of replication (ori):
   • This is a sequence from where replication starts and any piece of DNA when linked to this sequence can be made to replicate within the host cells.
   • This sequence is also responsible for controlling the copy number of the linked DNA.
   • So, if one wants to recover many copies of the target DNA it should be cloned in a vector whose origin support high copy number.
2. Selectable marker:
   • In addition to ‘ori’, the vector requires a selectable marker, which helps in identifying and eliminating non-transformants and selectively permitting the growth of the transformants.
3. Cloning sites:
   • In order to link the alien DNA, the vector needs to have very few, preferably single, recognition sites for the commonly used restriction enzymes.
   • The ligation of alien DNA is carried out at a restriction site present in one of the two antibiotic resistance genes.

Explanation:

• For example, the above figure is of plasmid pBR322, which is a cloning vector.
• It contains an origin of replication (ori).
• It has several cloning sites like PstI, PvuI, EcoRI, BamHI and SalI.
• The selectable markers here are ampicillin resistance (amp^R) and tetracycline resistance (tet^R).

Key Points

• Golden rice is a transgenic rice variety.
• Transgenic plants are obtained through genetic engineering that uses recombinant DNA technology.
• Transgenic plants are generated by introducing foreign DNA into a cell and regenerating a plant from that cell.

Explanation:

• Golden rice is rich in vitamin A.
• It is a genetically modified variety of rice (Oryza sativa).
• It contains good quantities of β-carotene, the precursor of vitamin A.
• The rice grains are yellow in colour due to presence of β-carotene, thus it is commonly called golden rice.
• This strain of rice is developed to deal with the vitamin A deficiency in nutrient deficient population.
• It is one of the successfully biofortified food.

Hence, the correct option is (1) vitamin A.

Additional Information

• Genetically modified plants contain high nutritional value of food.
• Genetic modification has made crops more tolerant to the abiotic stress, and helped to post harvest losses.
• Reduced reliance on chemical pesticides and increased efficiency of mineral usage by plants.
• Example- Flavr savr tomatoes, Bt cotton, etc.

Concept-

• Recombinant DNA technology is the technology of joining together DNA molecules from two different species that are inserted into a host organism to produce new genetic combinations.
• Process of Recombinant DNA Technology-
  • Recombinant DNA technology involves several steps in a specific sequence:
  • Isolation of Genetic Material
  • Cutting the gene at the recognition sites
  • Ligation of DNA Molecules
  • The DNA molecule thus produced is called recombinant DNA.
  • Insertion of Recombinant DNA into Host
  • The recombinant DNA molecule produces new genetic combinations that are of value to science, medicine, agriculture, and industry.

Key Points

Dolly is not a product of Recombinant DNA Technology

• Cloning is the production of an exact copy of a cell, any other living part, or a complete organism.
• Cloning of an animal was successfully performed for the first time by Ian Wilmut and his colleagues at the Roslin Institute in Edinburgh, Scotland.
• They cloned successfully a sheep named Dolly.
• Dolly was born on 5th July 1996 and was the first mammal to be cloned.

Additional Information

Bt-cotton

• Some strains of Bacillus thuringiensis produce proteins that kill certain insects such as lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes).
• B. thuringiensis forms protein crystals during a particular phase of their growth.
• These crystals contain a toxic insecticidal protein.

Flavr savr

• Flavr Savr, a genetically modified tomato, was the first commercially grown genetically engineered food to be granted a license for human consumption.
• It was produced by the Californian company Calgene and submitted to the U.S. Food and Drug Administration (FDA) in 1992.
• Tomatoes have a short shelf-life in which they remain firm and ripe.

GloFish

• GloFish is a genetically modified fish that was made using Recombinant DNA Technology.
• These fishes displays bio-chemiLuminescence.

The correct answer is option 2.

Key Points

• GMO (Genetically Modified Organisms)
  •  Techniques to alter the chemistry of genetic material (DNA and RNA), to introduce these into host organisms and thus change the phenotype of the host organism.
  • The techniques of genetic engineering include
    • the creation of recombinant DNA, use of gene cloning, gene transfer, overcome this limitation and allow us to isolate and introduce only one or a set of desirable genes without introducing undesirable genes into the target organism.
  • In this technique, a gene from one organism is isolated and transferred to the cell of another organism. Hence statement 1 is correct.
  • A genetically modified organism (GMO) is an animal, plant, or microbe whose DNA has been altered using genetic engineering techniques. Hence statement 2 is not correct.
  • Genes for insect resistance may spread from crop plants to wild plants. Hence statement 3 is correct.
  • Animals that have had their DNA manipulated to possess and express an extra (foreign) gene are known as transgenic animals.
  • To produce a transgenic animal the novel genes are inserted at a very early stage of development. Hence statement 4 is correct.