Biotechnological Applications in Agriculture Questions in English

(C) Basmati rice is well-known for its distinct aroma and flavor. There are $27$ documented varieties of Basmati rice that are traditionally cultivated in India. This fact is significant in the context of biopiracy and patenting issues related to Indian agricultural resources.

(C) Both statements are correct.
$GEAC$ (Genetic Engineering Appraisal Committee) was set up by the Ministry of Environment and Forests to regulate research,testing,and commercial release of $GM$ crops,food,and organisms.
The aims and objectives of $GEAC$ are:
$(i)$ To permit the use of $GM$ organisms and their products for commercial applications.
$(ii)$ To adopt procedures for restriction,production at scale,import,export,and application of $GM$ organisms.
$(iii)$ To provide approval to conduct large-scale field trials and the release of transgenic crops into the environment.
$(iv)$ To authorize agencies or persons to have large-scale production and the release of $GM$ organisms into the environment,or to curb and take punitive action against them.

(C) $Bacillus \text{ } thuringiensis$ \text{ } \text{bacteria produce } Bt \text{ } \text{toxin in an inactive form known as protoxin. }
\text{When an insect ingests these crystals, the alkaline } pH \text{ of the insect's gut solubilizes the crystals and converts the inactive protoxin into an active toxin. }
\text{Since the toxin is inactive within the bacterial cell, it does not harm the bacterium itself.}

(C) The $Bt$ toxin is produced by a bacterium called $Bacillus$ $thuringiensis$. This toxin is coded by a gene named $cry$.
There are a number of such genes,for example,the proteins encoded by the genes $cry$ $IAc$ and $cry$ $IIAb$ are used to control cotton bollworms.
Similarly,the gene $cry$ $IAb$ is used to control corn borer.

(B) The nematode $Meloidogyne$ $incognitia$ infects the roots of tobacco plants,which significantly reduces tobacco production.
This can be prevented by using the $RNA$ interference $(RNAi)$ process.
In this process,by using an $Agrobacterium$ vector,nematode-specific genes are introduced into the host plant.
These genes produce both sense and antisense $RNA$ in the host cells,which form double-stranded $RNA$ $(dsRNA)$.
This $dsRNA$ initiates $RNAi$,which silences the specific $mRNA$ of the nematode,thereby preventing its survival in the host plant.

(D) $Bt$ cotton is a genetically modified $(GM)$ crop that expresses a bacterial gene from $Bacillus$ $thuringiensis$ to provide resistance against specific insect pests. However,it is not resistant to all pesticides. Pesticides are chemicals used to kill pests,and $Bt$ cotton does not inherently possess resistance to all types of chemical pesticides.

(A) The correct answer is the alkaline $pH$ of the gut.
$Bt$ toxin is an intracellular crystalline protein. Specific $Bt$ toxin genes obtained from $Bacillus$ $thuringiensis$ are used in several crop plants like cotton. $Bt$ toxins are initially produced as inactive protoxins. After ingestion by the insects,the inactive toxin becomes active due to the alkaline $pH$ of the gut,which dissolves the crystals and releases the active toxin.

(C) Gene silencing is a biological process in which the expression of a specific gene is suppressed or turned off.
This can be achieved through $RNA$ interference $(RNAi)$,which uses double-stranded $RNA$ to trigger the degradation of complementary $mRNA$.
Additionally,antisense $RNA$ technology can be used,where an $RNA$ molecule complementary to the target $mRNA$ is introduced to prevent its translation.
Therefore,both $RNAi$ and antisense $RNA$ are effective methods for gene silencing.

(D) The applications of biotechnology include:
$(i)$ Therapeutics
$(ii)$ Diagnostics
$(iii)$ Genetically modified crops for agriculture
$(iv)$ Processed food
$(v)$ Bioremediation
$(vi)$ Waste treatment
$(vii)$ Energy production
Conventional hybridization is a traditional breeding method used in plant and animal breeding,which is distinct from modern biotechnology techniques that involve genetic manipulation.

(D) Golden rice is a genetically modified (transgenic) crop developed to address vitamin-$A$ deficiency.
$I$. It is a transgenic variety of rice,which is correct.
$II$. It is engineered to produce high levels of $\beta$-carotene,which is a precursor (provitamin-$A$) to vitamin-$A$,which is correct.
$III$. $\beta$-carotene is converted into vitamin-$A$ in the human body,making it a principal source,which is correct.
$IV$. The accumulation of $\beta$-carotene gives the rice grains a characteristic golden-yellow colour,hence the name 'Golden rice',which is correct.
Therefore,all statements $I$,$II$,$III$,and $IV$ are correct.

(D) $Bt$ toxin is not toxic to human beings because the conversion of the inactive pro-$Bt$ toxin to the active $Bt$ toxin state takes place only in highly alkaline conditions.
In the gut of the target insect,the alkaline $pH$ solubilizes the crystals,allowing the toxin to become active.
In contrast,the human stomach has an acidic $pH$,which does not facilitate this conversion,thus rendering the toxin harmless to humans.

(A) Genetic modification $(GM)$ in plants has several advantages:
$I$. It has reduced reliance on chemical pesticides by creating pest-resistant crops (e.g.,$Bt$ cotton).
$II$. It has reduced post-harvest losses by increasing the shelf life of produce (e.g.,Flavr Savr tomato).
$III$. It has increased the efficiency of mineral usage by plants,which prevents the early exhaustion of soil fertility.
$IV$. It has enhanced the nutritional value of food (e.g.,Golden rice,which is rich in Vitamin $A$).
Therefore,all four statements $(I, II, III, IV)$ are correct.

(D) $(I)$ Fruit softening is promoted by the enzyme polygalacturonase,which degrades pectin. In the transgenic tomato variety Flavr Savr,the production of polygalacturonase was blocked; hence,the fruit of this tomato variety remains fresh and retains its flavour much longer than the fruit of normal tomato varieties.
$(II)$ Recently,the $US$ government patented Indian Basmati rice as 'Rice Tec'. The Government of India challenged this on April $28, 2001$. Consequently,the $USPTO$ served a notice to $M/s$ Rice Tec,Inc.,for amendments in claims,restricting them to only three strains developed by it.
$(III)$ The war fought using bioweapons (biological weapons) against humans or their crops and animals is called biowar. Viruses,bacteria,and some other harmful organisms can be used as bioweapons in biological warfare.

(D) $Bt$ toxin,produced by $Bacillus \; thuringiensis$,has been cloned and expressed in plants to provide resistance to insects,effectively creating a biopesticide.
$RNAi$ ($RNA$ interference) involves the silencing of a specific $mRNA$ due to the formation of a $dsRNA$ molecule,which binds to the complementary $mRNA$,thereby preventing translation.
Gene therapy is a collection of methods that allow for the correction of a gene defect that has been diagnosed in a child or embryo. It is not used for creating pest-resistant plants.

(B) $GM$ crops (Genetically Modified crops) are engineered to provide various benefits. Increased reliance on chemical pesticides is not an advantage; in fact,$GM$ crops like $Bt$ cotton are designed to reduce the need for chemical pesticides by providing built-in pest resistance. Other options like increased salt tolerance,reduced post-harvest losses,and improved mineral usage efficiency are well-documented advantages of $GM$ technology.

(C) The primary objective of developing pest-resistant plants (such as $Bt$ cotton) is to make the plants inherently capable of defending themselves against specific insect pests.
Since the plants produce their own toxins to kill the pests,the reliance on external chemical pesticides is significantly reduced.
Therefore,the production of pest-resistant plants leads to a decrease in the amount of pesticide used in agriculture.

(A) The $Bt$ toxin is produced by a bacterium called $Bacillus\; thuringiensis$.
This toxin is encoded by a specific gene known as the $cry$ gene.
There are various types of $cry$ genes that control different insect pests.
Specifically,the gene $cry\; I\; Ab$ encodes the protein $Cry\; I\; Ab$,which is responsible for controlling the corn borer.

(D) $Bacillus$ $thuringiensis$ $(Bt)$ produces insecticidal crystalline proteins called $Cry$ proteins in an inactive protoxin form.
These crystals remain inactive in the bacterium because the $pH$ of the bacterial cytoplasm is neutral.
When an insect ingests the $Bt$ crystals,the alkaline $pH$ of the insect's mid-gut solubilizes the crystals and activates the toxin.
The activated toxin then binds to the surface of mid-gut epithelial cells,creating pores that cause cell swelling and lysis,eventually leading to the death of the insect.

(D) After ingestion by the insect,the inactive protoxin is converted into an active toxin due to the alkaline $pH$ of the insect's gut.
This active toxin binds to the surface of the mid-gut epithelial cells.
It creates pores in the mid-gut epithelial cell membrane,which leads to cell swelling and lysis.
Consequently,the insect is unable to feed and eventually dies due to starvation.

(B) According to the $NCERT$ textbook (Biology,Class $12$,Chapter $12$: Biotechnology and its Applications),there are $27$ documented varieties of basmati rice grown in India. These varieties are diverse and have been cultivated in the country for many years.

(D) Neem: In $1996$,Vandana Shiva challenged the patent granted to the firm of $W.R.$ Grace & Co. by the European Patent Office,Munich for 'fungicidal uses of neem oil'.
Turmeric: In May $1995$,the $US$ Patent Office granted to the University of Mississippi Medical Center a patent for 'Use of Turmeric in Wound Healing'.
Daffodil: It is a plant used for genetic engineering to produce $\beta$-carotene (Golden Rice),but it is not a case of biopiracy of an Indian plant by western nations.
Therefore,both Neem and Turmeric are classic examples of biopiracy where western nations attempted to patent traditional Indian knowledge.

(B) $Bacillus$ $thuringiensis$ (often abbreviated as $Bt$) is a soil-dwelling bacterium that produces insecticidal crystal proteins (Cry proteins) during sporulation.
These proteins are toxic to specific insect larvae,such as those of lepidopterans,coleopterans,and dipterans.
Because of this property,$Bt$ is extensively used in modern biotechnology as a bioinsecticide to control pests in agriculture,either by direct application of bacterial spores or by developing genetically modified crops (like $Bt$ cotton) that express the toxin gene.

(A) Flavr Savr: $A$ transgenic tomato in which the expression of a native tomato gene has been blocked to increase shelf life.
Meloidogyne incognita: $A$ nematode that infects the roots of tobacco plants.
Caenorhabditis elegans: $A$ free-living nematode worm used as a model organism.
Oryza sativa: The scientific name of rice,which is a natural crop species.
Therefore,Flavr Savr is the correct example of a transgenic plant.

(A) The gene encoding for hirudin, an anticoagulant protein originally found in leeches, was synthesized and introduced into the plant $Brassica \text{ } napus$.
This transgenic plant accumulates hirudin in its seeds.
The hirudin is then isolated and purified from these seeds for medical use.

(D) $RNAi$ ($RNA$ interference) is a method of cellular defense in all eukaryotic organisms. It involves the silencing of a specific $mRNA$ due to a complementary $dsRNA$ molecule that binds to and prevents the translation of the $mRNA$ (silencing). Therefore,the statement that $dsDNA$ or $ssRNA$ initiates $RNAi$ is incorrect. $dsRNA$ is the active molecule required for this process.

(B) Andrew Fire and Craig Mello were awarded the Nobel Prize in Physiology or Medicine in $2006$ for their discovery of $RNA$ interference $(RNAi)$. They conducted their groundbreaking research on the nematode worm $Caenorhabditis$ $elegans$. $RNAi$ is a biological process in which $RNA$ molecules inhibit gene expression or translation,by neutralizing targeted $mRNA$ molecules.

(B) $Bt$ toxin is produced by the bacterium $Bacillus$ $thuringiensis$.
This toxin is used to control various insect pests in genetically modified crops.
Tobacco budworm and armyworm are specific types of pests that belong to the order $Lepidoptera$.
Other insects controlled by $Bt$ toxins include coleopterans (beetles) and dipterans (flies and mosquitoes).

(C) In $1997$,an American company named RiceTec Inc. was granted a patent by the $U.S.$ Patent and Trademark Office for 'Basmati' rice lines and grains. This was controversial because $Basmati$ rice has been grown in India for centuries and is a traditional variety of the Indian subcontinent. The patent allowed the company to call their rice 'Basmati' in the $U.S.$ market,which led to significant legal and ethical disputes regarding biopiracy.

(C) Golden rice is a genetically modified $(GM)$ variety of rice engineered to produce $\beta-carotene$,which is a precursor to vitamin $A$. This modification was introduced to address vitamin $A$ deficiency in populations that rely heavily on rice as a staple food. Therefore,$\beta-carotene$ is present in significantly higher concentrations in $GM$ rice compared to conventional rice.

(D) The genes $cry \; IAc$ and $cry \; IIAb$ are responsible for controlling cotton bollworms. The option $cry \; IIAc$ is incorrect because the specific gene combination for cotton bollworm is $cry \; IAc$ and $cry \; IIAb$. Therefore,$cry \; IIAc$ - Cotton bollworm is the incorrect match.

(B) $DNA$ vaccines are genetic vaccines that use the genetic material of the pathogen itself to immunize the individual.
$DNA$ vaccines induce both humoral and cell-mediated immunity.
These are primarily used in animals and humans for disease prevention,not as a direct application of genetic engineering in plants.

(C) $Bt$ toxin is not harmful to humans because it is specific to certain insect groups.
$Bt$ toxins are insect-group specific,meaning they target specific pests without affecting humans or other non-target organisms.

(D) The primary objective of developing herbicide-resistant $GM$ crops is to allow farmers to spray herbicides over the entire field to kill weeds without harming the crop plants.
This eliminates the need for manual weeding,which is labor-intensive and costly.
Option $(A)$ is incorrect because herbicide resistance does not necessarily reduce herbicide accumulation in food.
Option $(B)$ is incorrect because the use of herbicides is still required.
Option $(D)$ is incorrect as the use of herbicides can still lead to soil pollution and potential biomagnification.
Therefore,only statement $(C)$ correctly describes the main objective.

(A) $RNAi$ ($RNA$ interference) is a method of cellular defense that occurs in all eukaryotic organisms. This process involves the silencing of a specific $mRNA$ due to a complementary $dsRNA$ molecule that binds to and prevents the translation of the $mRNA$. Thus,both the Assertion and the Reason are correct,and the Reason provides the correct explanation for the Assertion.

(C) $Bt$ toxin is produced by the bacterium $Bacillus \text{ thuringiensis}$ $(Bt)$.
The bacterium produces protein crystals during a particular phase of their growth, which is the sporulation phase, not throughout their entire growth period.
These crystals contain a toxic insecticidal protein.
Therefore, the Assertion is correct, but the Reason is incorrect.

(A) The assertion is correct because hirudin is an anticoagulant protein originally found in leeches. When scientists attempted to produce it in transgenic $Brassica$ (mustard) plants,they used a synthetic gene because the natural eukaryotic gene contains introns.
The reason is also correct because eukaryotic genes contain non-coding sequences called introns,which must be removed (spliced) to produce functional mRNA. Bacteria and many plant expression systems cannot efficiently process these introns. Therefore,to express the protein in $Brassica$,a synthetic gene (cDNA) lacking introns was designed and inserted.
Since the presence of introns in the natural gene is the specific reason why a synthetic gene was required for successful expression,the Reason correctly explains the Assertion.

(A) Golden rice is a genetically modified crop engineered to produce $\beta$-carotene,which is a precursor to vitamin $A$.
Night blindness is primarily caused by a deficiency of vitamin $A$.
By consuming golden rice,individuals in developing nations can increase their intake of vitamin $A$,thereby helping to prevent and overcome night blindness.
Therefore,both the Assertion and the Reason are correct,and the Reason provides the correct explanation for the Assertion.

(B) Mutation breeding is a technique used in plant breeding to create genetic variation.
$Gamma$ rays are ionizing radiations that are commonly used as mutagens to induce mutations in plant cells.
These radiations cause changes in the $DNA$ sequence,which can lead to the development of new traits.
Kinetin and Zeatin are types of cytokinins (plant growth hormones) and are not used as mutagens.
Infrared rays are non-ionizing and do not have sufficient energy to induce mutations in $DNA$.

(A) $DDT$ (Dichlorodiphenyltrichloroethane) was the first synthetic insecticide used on a wide scale.
It effectively kills various pests and caterpillars that feed on crops,thereby preventing significant crop damage.
By reducing pest-related losses,it significantly increased agricultural productivity during its initial period of use.

(A) $IARI$ stands for Indian Agricultural Research Institute. It is a premier national institute for agricultural research,education,and extension in India,located in New Delhi.

(B) $BT$ cotton is a genetically modified pest-resistant plant cotton variety.
In this, $BT$ stands for the bacterium $Bacillus$ $thuringiensis$.
This bacterium produces insecticidal proteins (Cry proteins) that are toxic to certain insect pests, such as bollworms, protecting the cotton crop from damage.

(A) The term $GMO$ stands for $Genetically$ $Modified$ $Organisms$.
These are organisms (plants,animals,or microorganisms) in which the genetic material $(DNA)$ has been altered in a way that does not occur naturally by mating or natural recombination.
This is achieved through genetic engineering techniques to introduce desirable traits.

(B) Biotechnology has various applications in different fields.
$I -$ Therapeutics: Used in the production of recombinant therapeutics like insulin.
$II -$ Diagnostics: Used in molecular diagnostic techniques like $PCR$ and $ELISA$.
$III -$ Genetically modified crops: Used to create $GM$ crops for pest resistance and higher yield.
$V -$ Nutritionally enhanced foods: Used in biofortification (e.g.,Golden Rice).
$VI -$ Bioremediation: Used to clean up contaminated environments.
$VII -$ Waste treatment: Used in the treatment of industrial and municipal waste.
$IX -$ Energy production: Used in the production of biofuels.
$IV$ (Traditional hybridization) and $VIII$ (Animal poaching) are not applications of biotechnology.
Therefore,the correct fields are $I, II, III, V, VI, VII, IX$.

(A) $GMO$ stands for Genetically Modified Organisms.
These are plants,bacteria,fungi,and animals whose genes have been altered by manipulation for various purposes such as increased yield,pest resistance,or nutritional enhancement.

(C) Golden rice is a genetically modified variety of rice $(Oryza sativa)$ engineered to produce beta-carotene, which is a precursor of Vitamin $A$.
This modification was introduced to address Vitamin $A$ deficiency in populations that rely on rice as a staple food.
Therefore, the correct option is $C$.

(A) Genetically modified $(GM)$ crops are developed to enhance agricultural productivity and sustainability. The primary objectives include:
$1$. Making crops more tolerant to abiotic stresses (cold,drought,salt,heat),not intolerant.
$2$. Reducing reliance on chemical pesticides (pest-resistant crops).
$3$. Increasing efficiency of mineral usage by plants (preventing early exhaustion of soil fertility).
$4$. Helping to reduce post-harvest losses.
Option $A$ states that $GM$ crops are made more 'intolerant' to abiotic stresses,which is incorrect; they are designed to be more 'tolerant'.

(B) $Bt$ cotton is a genetically modified organism $(GMO)$ that produces an insecticidal protein.
In this context,$Bt$ stands for the bacterium $Bacillus$ $thuringiensis$.
This bacterium produces a crystal $(Cry)$ protein that is toxic to certain insect larvae,such as the cotton bollworm,providing the plant with natural resistance.

(C) The $Cry$ genes are derived from the bacterium $Bacillus \ thuringiensis$ $(Bt)$.
$CryIAc$ and $CryIIAb$ are specifically used to control cotton bollworms.
$CryIAb$ is used to control the corn borer.
Therefore,the correct matching is: Cotton bollworms $(I, III)$ and Corn borer $(II)$.

(D) The $Cry$ genes are derived from the bacterium $Bacillus$ $thuringiensis$ $(Bt)$.
These genes encode for insecticidal proteins that are toxic to specific insect pests.
Scientists have successfully introduced these $Cry$ genes into various crop plants to confer resistance against pests.
Examples of such genetically modified crops include $Bt$ cotton,$Bt$ corn (maize),$Bt$ rice,$Bt$ tomato,$Bt$ potato,and $Bt$ soybean.
Therefore,all the listed options are correct as $Cry$ genes have been introduced into these plants.

(B) $Bacillus \text{ } thuringiensis$ $(Bt)$ is a soil bacterium that produces insecticidal proteins.
These proteins are used to create transgenic crops, such as $Bt \text{ } cotton$, which are resistant to specific insect pests.
Therefore, $Bt$ is primarily used in the development of biopesticidal plants (genetically modified crops) that express the $cry$ genes to kill pests.