Indian Administrative Service IAS Agriculture Optional Paper 2 Solutions- Section B Question 5,6
5. (a) Give a detailed account of sucrose metabolism in plants.
Answer: Sucrose is the most abundant carbohydrate in plants and is a crucial molecule for plant growth and development. Plants use sucrose for energy production, as a carbon source for biosynthesis, and for long-term storage. Sucrose metabolism in plants involves a complex network of enzymes, transporters, and regulatory factors. In this answer, we will provide a detailed account of sucrose metabolism in plants, including its biosynthesis, transport, and utilization.
Biosynthesis of Sucrose:
Sucrose is synthesized in the cytoplasm of plant cells through the process of photosynthesis. During photosynthesis, plants capture light energy and use it to convert carbon dioxide (CO2) and water (H2O) into glucose (C6H12O6) and oxygen (O2). Glucose is then converted into sucrose through a series of enzymatic reactions. The first step in sucrose biosynthesis is the conversion of glucose-6-phosphate (G6P) into fructose-6-phosphate (F6P) by the enzyme phosphohexose isomerase. F6P is then converted into fructose-1,6-bisphosphate (FBP) by the enzyme aldolase. FBP is split into two three-carbon molecules, dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (GAP), by the enzyme fructose-1,6-bisphosphate aldolase. Finally, sucrose is formed by the transfer of a glucose molecule from UDP-glucose to fructose, catalyzed by the enzyme sucrose synthase. Transport of Sucrose:
Once synthesized, sucrose is transported from the leaves, where it is produced, to the rest of the plant via the phloem. The phloem is a specialized tissue that transports nutrients, including sucrose, from source tissues (such as leaves) to sink tissues (such as roots or developing fruits). Sucrose is loaded into the phloem in the source tissue by sucrose transporters, which are located in the plasma membrane of phloem companion cells. The sucrose transporters use a proton gradient generated by the plasma membrane H+-ATPase to drive sucrose uptake from the cytoplasm. Sucrose is then transported through the phloem in the form of a sucrose-rich sap. In the sink tissue, sucrose is unloaded from the phloem by sucrose transporters and metabolized for energy or storage. Utilization of Sucrose:
Sucrose is utilized by plant cells for energy production, biosynthesis, and storage. In sink tissues, sucrose is hydrolyzed into glucose and fructose by the enzyme invertase. Glucose and fructose are then metabolized through glycolysis, the tricarboxylic acid (TCA) cycle, and the electron transport chain to generate ATP for energy production. Alternatively, sucrose can be stored as starch in storage organs such as roots, tubers, or seeds. Starch is synthesized through the conversion of glucose-6-phosphate into ADP-glucose by the enzyme ADP-glucose pyrophosphorylase. ADP-glucose is then polymerized into amylose and amylopectin by the enzymes starch synthase and branching enzyme. In addition to starch synthesis, sucrose is also used as a precursor for biosynthesis of other molecules such as cellulose, hemicellulose, and pectin. In summary, sucrose metabolism in plants is a complex process that involves the synthesis of sucrose in the cytoplasm through photosynthesis, transport of sucrose through the phloem, and utilization of sucrose for energy production, biosynthesis, and storage.
(b) Enlist and explain the symptoms of plant diseases that disrupt the photosynthesis function.
Answer: Plant diseases can disrupt the process of photosynthesis, which is the process by which plants convert sunlight into energy. The following are some symptoms of plant diseases that affect the photosynthesis function: Yellowing of leaves: If the leaves of a plant turn yellow, it can indicate that the plant is not producing enough chlorophyll, the pigment that absorbs sunlight and facilitates photosynthesis. This could be due to a disease that is affecting the plant's ability to produce chlorophyll. Stunted growth: Plants that are not able to photosynthesize properly may experience stunted growth. This is because they are not able to produce enough energy to support their growth. Wilting: A plant that is not able to photosynthesize properly may wilt or droop. This is because the plant is not producing enough energy to maintain turgor pressure, which is what keeps the plant upright. Reduced yield: Plants that are not able to photosynthesize properly may produce a reduced yield. This is because they are not able to produce enough energy to support the production of fruit or flowers. Necrosis: Necrosis is the death of plant tissue, which can be caused by diseases that disrupt photosynthesis. If a plant's leaves or other tissues become necrotic, it can indicate that the plant is not able to produce enough energy to maintain the health of its tissues. Changes in leaf color: In addition to yellowing, plants with photosynthesis disruptions may display other changes in leaf color, such as browning or reddening. These changes can indicate that the plant is not producing enough chlorophyll or is experiencing other stressors.
It's important to note that these symptoms can be caused by a variety of factors, not just plant diseases. If you suspect that your plant is suffering from a disease that is disrupting photosynthesis, it's important to consult with a plant health expert or a professional horticulturist to properly diagnose the issue and determine the appropriate course of treatment.
(c) What are pesticide formulations? Discuss the different types of formulations used in pest control.
Answer: Pesticide formulations refer to the physical form in which pesticides are prepared for use in pest control. Different formulations are designed to meet specific requirements of different applications, such as target pests, application methods, and environmental conditions. Here are some of the different types of formulations used in pest control: Liquid formulations: These are the most common type of pesticide formulations and are generally applied with a sprayer. They can be further classified as emulsifiable concentrates (EC), suspension concentrates (SC), soluble concentrates (SL), and microencapsulated formulations. EC formulations contain a pesticide dissolved in a liquid carrier and require thorough agitation before use. SC formulations contain a finely divided pesticide suspended in a liquid carrier and require less agitation. SL formulations are similar to EC formulations but are designed to dissolve quickly in water. Microencapsulated formulations contain tiny particles of pesticide enclosed in a capsule, which provides slow-release and long-lasting effects. Granular formulations: Granular formulations consist of pellets or beads that can be applied with a spreader or by hand. They are often used for treating soil, lawns, and gardens. Granular formulations are available in slow-release or quick-release forms, depending on the application requirements. Dust formulations: Dust formulations are powders that can be applied with a duster or blower. They are commonly used in the treatment of wall voids, attics, and crawl spaces, and can be effective against pests that are difficult to reach with other formulations. Baits: Baits are formulated as attractive food or lures for the target pests, which contain a pesticide that is consumed by the pest when ingesting the bait. Baits are usually used for the control of ants, cockroaches, and rodents, and are available in granular or gel formulations. Aerosol formulations: Aerosol formulations are spray cans that contain a pressurized mixture of a pesticide and propellant. They are commonly used for the control of flying insects, such as mosquitoes and flies, and are convenient for spot treatments. Overall, the choice of formulation depends on the target pest, the application method, and the environmental conditions in which the pesticide will be used. It is important to follow label instructions carefully and use appropriate personal protective equipment when handling and applying any pesticide formulation.
(c) Enlist and explain the salient features of the Public Distribution System as per the provisions of the National Food Security Act, 2013.
Answer: The Public Distribution System (PDS) is a government-sponsored program aimed at providing food security to the poor and vulnerable sections of society. The National Food Security Act, 2013, outlines the salient features of the PDS, which are as follows: Coverage: The Act ensures that 75% of the rural population and 50% of the urban population are covered under the PDS. This coverage ensures that a significant proportion of the population has access to essential food items at subsidized rates. Entitlements: The Act provides for the entitlement of subsidized food grains to eligible households. The entitled households are categorized as priority and general households. The former category includes households identified by the state government as poor and vulnerable, and the latter category includes all other households. Quantity of food grains: The Act provides for a minimum quantity of food grains that each entitled household is entitled to receive from the PDS. This quantity is five kg per person per month for priority households and three kg per person per month for general households. Subsidized prices: The Act provides for the sale of food grains at subsidized prices to entitled households. The prices are fixed by the central government and are uniform across the country. For example, the subsidized price for rice is Rs. 3 per kg, and for wheat, it is Rs. 2 per kg. Fair price shops: The Act mandates the establishment of fair price shops to distribute food grains to entitled households. These shops are run by the state government or authorized dealers, and they are required to maintain records of sales and stocks. Transparency and accountability: The Act provides for the use of technology to improve transparency and accountability in the PDS. The state governments are required to computerize their PDS operations and put in place an end-to-end computerized supply chain management system. Grievance redressal: The Act provides for a grievance redressal mechanism to address the complaints of entitled households. The mechanism includes setting up toll-free helplines, establishing vigilance committees at the district and state levels, and conducting social audits. In summary, the National Food Security Act, 2013, ensures that the PDS is more effective in providing food security to the poor and vulnerable sections of society. The Act has provisions to ensure that entitled households receive adequate quantities of food grains at subsidized prices, and that the PDS operations are transparent and accountable.
(d) Enlist and explain the efforts of the Government of India in streamlining the current levels of poverty. Answer: The Government of India has taken various initiatives to streamline the current levels of poverty. Here are some of the efforts undertaken by the government: National Rural Employment Guarantee Act (NREGA): NREGA provides a legal guarantee for 100 days of wage employment in a financial year to every household whose adult members volunteer to do unskilled manual work. The aim of the scheme is to enhance the livelihood security of rural households by providing wage employment opportunities. Pradhan Mantri Awaas Yojana (PMAY): PMAY aims to provide affordable housing to the urban and rural poor by 2022. Under this scheme, the government provides financial assistance to eligible beneficiaries for the construction of a pucca house with basic amenities. National Food Security Act (NFSA): NFSA provides for the supply of subsidized food grains to the eligible households under the Targeted Public Distribution System (TPDS). The aim of the scheme is to ensure food security to the vulnerable sections of society. Swachh Bharat Abhiyan (SBA): SBA aims to make India clean and free of open defecation by 2nd October 2019. The aim of the scheme is to promote cleanliness, hygiene, and sanitation in rural and urban areas. Jan Dhan Yojana: The Jan Dhan Yojana aims to provide banking facilities to all households in the country. Under this scheme, every household is entitled to open a bank account with zero balance. This initiative aims to promote financial inclusion and empower the poor. Ayushman Bharat: Ayushman Bharat aims to provide financial protection to poor and vulnerable families against catastrophic health expenditures. The scheme provides health insurance cover of up to Rs. 5 lakhs per family per year for secondary and tertiary care hospitalization. These are some of the efforts undertaken by the Government of India to streamline the current levels of poverty. These initiatives aim to provide basic amenities and social protection to the vulnerable sections of society.
6. (a) Describe the vicious cycle of poverty and enlist the existing policy instruments
for combating malnutrition.
Answer: The Government of India has taken various initiatives to streamline the current levels of poverty. Here are some of the efforts undertaken by the government:
National Rural Employment Guarantee Act (NREGA): NREGA provides a legal guarantee for 100 days of wage employment in a financial year to every household whose adult members volunteer to do unskilled manual work. The aim of the scheme is to enhance the livelihood security of rural households by providing wage employment opportunities.
Pradhan Mantri Awaas Yojana (PMAY): PMAY aims to provide affordable housing to the urban and rural poor by 2022. Under this scheme, the government provides financial assistance to eligible beneficiaries for the construction of a pucca house with basic amenities.
National Food Security Act (NFSA): NFSA provides for the supply of subsidized food grains to the eligible households under the Targeted Public Distribution System (TPDS). The aim of the scheme is to ensure food security to the vulnerable sections of society.
Swachh Bharat Abhiyan (SBA): SBA aims to make India clean and free of open defecation by 2nd October 2019. The aim of the scheme is to promote cleanliness, hygiene, and sanitation in rural and urban areas.
Jan Dhan Yojana: The Jan Dhan Yojana aims to provide banking facilities to all households in the country. Under this scheme, every household is entitled to open a bank account with zero balance. This initiative aims to promote financial inclusion and empower the poor.
Ayushman Bharat: Ayushman Bharat aims to provide financial protection to poor and vulnerable families against catastrophic health expenditures. The scheme provides health insurance cover of up to Rs. 5 lakhs per family per year for secondary and tertiary care hospitalization.
These are some of the efforts undertaken by the Government of India to streamline the current levels of poverty. These initiatives aim to provide basic amenities and social protection to the vulnerable sections of society.
(b) Enlist and explain Dos' and 'Don'ts' of pesticide usage with reference to the purchase, handling, application, and disposal of pesticides.
Read the label: Always read the label before purchasing, handling, and using any pesticide. The label contains essential information about the product, including the active ingredients, instructions for use, and safety precautions.
Wear protective clothing: When handling pesticides, it is crucial to wear appropriate protective clothing, including gloves, goggles, a respirator, and long-sleeved shirts and pants.
Use the right amount: Using too little pesticide may not be effective, while using too much may be harmful to the environment and human health. Always use the recommended amount as stated on the label.
Store pesticides properly: Store pesticides in a cool, dry, and well-ventilated area. Keep them away from food, children, and pets.
Clean equipment: After use, clean all equipment thoroughly with soap and water to prevent cross-contamination.
Proper disposal: Properly dispose of unused pesticides and empty containers. Follow the label instructions for disposal or contact your local waste management facility for guidance.
Don't use outdated pesticides: Pesticides have an expiration date. Using outdated pesticides may result in poor performance or even harm to the environment and human health.
Don't use in windy or rainy conditions: Pesticides may drift and spread to non-target areas when used in windy or rainy conditions, which may harm the environment, including humans, animals, and plants.
Don't mix different pesticides: Mixing different pesticides may create a dangerous chemical reaction and produce harmful fumes, which may be harmful to the environment and human health.
Don't store pesticides near food: Pesticides should be stored away from food, as they may contaminate it, leading to food poisoning.
Don't pour pesticides down the drain: Pesticides should not be poured down the drain, as they may contaminate the water supply, harm aquatic life, and pollute the environment.
Don't use pesticides near water bodies: Pesticides should not be used near water bodies, such as ponds, lakes, and streams, as they may harm aquatic life and pollute the water.
(c) Define biotic stress in plants. Explain the role of salicylic acid in a plant's response to biotic stress.
Answer: Biotic stress in plants refers to the damage or harm caused to plants by living organisms such as pathogens, insects, or pests. These organisms can cause diseases, inhibit growth, and reduce crop yield, resulting in significant economic losses for farmers and agricultural industries.
Salicylic acid (SA) is a plant hormone that plays a crucial role in a plant's response to biotic stress. SA triggers a range of physiological and biochemical changes in the plant, leading to the activation of defense mechanisms against biotic stress.
When a plant is exposed to biotic stress, SA levels increase in the plant tissue. This increase in SA triggers a signaling pathway that activates the plant's defense mechanisms. SA induces the expression of genes that produce proteins that are toxic to the invading pathogen or repel insects and pests.
SA also induces the production of reactive oxygen species (ROS), which are toxic to the pathogen and can trigger cell death in the infected plant tissue. This programmed cell death prevents the spread of the pathogen to healthy plant tissue.
Furthermore, SA regulates the production of other hormones such as jasmonic acid and ethylene, which are also involved in plant defense against biotic stress. SA promotes the synthesis of enzymes that degrade cell walls, making it harder for the pathogen to invade the plant tissue.
In summary, SA plays a critical role in a plant's defense against biotic stress by triggering the activation of defense mechanisms, inducing the production of toxic proteins, activating the programmed cell death response, and regulating the production of other hormones involved in plant defense.