Role of Macro and Micro-nutrients Questions in English

(C) The $enolase$ enzyme, which catalyzes the conversion of $2-phosphoglycerate$ to $phosphoenolpyruvate$ during glycolysis, requires divalent metal ions for its catalytic activity. $Magnesium$ $(Mg^{2+})$ is the essential cofactor that binds to the enzyme to stabilize the transition state and facilitate the reaction.

(D) Sulphydryl enzymes contain $-SH$ groups at their active sites,which are essential for their catalytic activity.
Heavy metals like lead $(Pb^{2+})$ have a high affinity for these sulphydryl $(-SH)$ groups.
When lead binds to these groups,it forms stable mercaptides,which block the active site and inhibit the enzyme's function.
Therefore,$Pb$ is a known inhibitor of sulphydryl enzymes.

(D) Potassium $(K^+)$ ions play a crucial role in the movement of water into and out of guard cells.
When $K^+$ ions enter the guard cells,the osmotic pressure increases,causing water to enter,which leads to the turgidity of the guard cells and the opening of the stomata.
Conversely,when $K^+$ ions exit,the guard cells lose turgidity,leading to the closing of the stomata.
Therefore,potassium is essential for the opening and closing of stomata.

(D) Boron is essential for the translocation of sugars in plants.
It facilitates the movement of carbohydrates from source to sink by forming a sugar-borate complex,which is more easily transported across cell membranes.

(B) The chlorophyll molecule consists of a porphyrin ring (head) and a phytol tail.
At the center of the porphyrin ring,a magnesium ion $(Mg^{2+})$ is coordinated with four nitrogen atoms.
Therefore,$Mg$ is an essential structural component of the chlorophyll molecule.

(B) $Mg$ is a central constituent of the chlorophyll molecule,forming the core of the porphyrin ring,which is essential for its structure and function.
$Fe$ (Iron) is not a structural component of chlorophyll,but it is absolutely essential for the biosynthesis of chlorophyll molecules as it acts as a cofactor for enzymes involved in the pathway.
Therefore,both $Fe$ and $Mg$ are required for the synthesis and maintenance of chlorophyll in plants.

(D) $NPK$ stands for Nitrogen $(N)$,Phosphorus $(P)$,and Potassium $(K)$.
These are the three primary macronutrients essential for the healthy growth and development of plants,especially in agricultural crops.
They are commonly used as the main components in commercial fertilizers to improve soil fertility.

(C) Sulphur is an essential macronutrient for plants. It is required for the synthesis of amino acids (cysteine and methionine),vitamins,and coenzymes. It is particularly concentrated in stem and root tips and young leaves. Furthermore,sulphur plays a crucial role in increasing nodule formation in the roots of leguminous plants,thereby promoting overall root development and nitrogen fixation.

(C) The middle lamella is a layer that cements the cell walls of two adjacent plant cells together.
It is primarily composed of calcium pectate and magnesium pectate.
Calcium is essential for the formation of these pectates,which provide structural stability to the cell wall.
Therefore,calcium is a key component of the middle lamella.

(A) Calcium,along with $Na^+$ and $K^+$,plays a crucial role in maintaining the permeability of the plasma membrane.
It is essential for the formation of the middle lamella in cell walls and is involved in the normal functioning of cell membranes.

(D) Sulphur is an essential macronutrient for plants,required for the synthesis of sulphur-containing amino acids like cysteine and methionine.
In maize grains,the concentration of sulphur is approximately $0.26\%$ of the dry weight.
Therefore,the correct option is $D$.

(C) Sulphur is a structural component of certain amino acids (cysteine and methionine) and vitamins (thiamine,biotin,coenzyme $A$,and ferredoxin). Because it is incorporated into structural proteins and is not easily remobilized from older tissues to younger tissues,it is considered relatively immobile in plants. Consequently,deficiency symptoms of sulphur appear first in young leaves.

(D) $Calcium$ $(Ca^{2+})$ is an essential mineral element that plays a crucial role in various physiological processes.
It is required for the metabolism of fats and carbohydrates, the assimilation of nitrates, and specifically for the binding of nucleic acids with proteins, such as in the formation of chromatin structures.

(B) Phosphorus is a vital component of energy-rich compounds such as $ATP$ $(Adenosine \text{ } Triphosphate)$.
It plays a crucial role in the transport and storage of energy within the cell.
Among the given options, phosphorus is specifically involved in the metabolic processes that facilitate the movement and utilization of $Zinc$ $(Zn)$ in various enzymatic activities and structural functions within plants.

(C) Potassium $(K^+)$ is an essential macronutrient for plants. It plays a crucial role in maintaining the turgor pressure of cells,which is essential for cell expansion and growth. Specifically,potassium is highly involved in the development and maintenance of $Parenchyma$ tissue,as it regulates osmotic potential and enzyme activation required for the synthesis of cell wall components and metabolic processes within these cells.

(A) Macro-nutrients are elements required by plants in large amounts (generally in excess of $10 \ mmol \ kg^{-1}$ of dry matter). These include Carbon,Hydrogen,Oxygen,Nitrogen,Phosphorus,Sulphur,Potassium,Calcium,and Magnesium.
$Mn$ (Manganese) is a micro-nutrient,which is required by plants in small amounts (less than $10 \ mmol \ kg^{-1}$ of dry matter). Therefore,$Mn$ is not a macro-nutrient.

(A) Phosphorus is a vital macronutrient for plants. It is a constituent of cell membranes,certain proteins,all nucleic acids,and nucleotides. It is required for all phosphorylation reactions. Phosphorus promotes healthy root growth and is essential for the development of seeds and fruits. It also plays a key role in the translocation of carbohydrates within the plant.

(A) Phosphorus plays an indispensable role in energy metabolism.
It is a key component of $ATP$ (Adenosine Triphosphate),which acts as the energy currency of the cell.
The hydrolysis of pyrophosphate and various organic phosphate bonds is used to drive numerous chemical reactions within the plant.
Therefore,phosphorus is essential for all phosphorylation reactions,which are fundamental to generating and transferring metabolic energy.

(B) The chlorophyll molecule consists of a porphyrin ring with a central $Mg^{2+}$ ion. Magnesium is a critical structural component of the chlorophyll molecule. Without magnesium,the synthesis of chlorophyll cannot occur,leading to chlorosis in plants.

(B) $Mg$ (Magnesium) is a central atom in the structure of the chlorophyll molecule,making it an essential constituent for its formation.
$Fe$ (Iron) is not a structural component of chlorophyll,but it is required as a cofactor for the enzymes involved in the biosynthesis of chlorophyll.
Therefore,both $Mg$ and $Fe$ are essential for the synthesis of chlorophyll pigments in leaves.

(B) Calcium is a structural component of the cell wall and is present as calcium pectate in the middle lamella.
Unlike mobile elements like nitrogen,phosphorus,and potassium,calcium is relatively immobile within the plant.
Because it is not remobilized from older tissues to younger ones,it tends to accumulate in older leaves and tissues as the plant ages.

(B) Calcium is essential for the formation of the middle lamella in plant cell walls.
It is present as calcium pectate in the middle lamella,which acts as a cementing material between adjacent cells.
Deficiency of calcium affects the meristematic tissues because cell division and cell wall formation are hindered.
This leads to the death of growing tips (apices) of roots and stems,and chlorosis of young leaves.

(A) Macronutrients are elements required by plants in large amounts (generally $ > 10 \text{ mmol kg}^{-1}$ of dry matter).
$Ca$ (Calcium) and $Mg$ (Magnesium) are classified as macronutrients.
$Mo$ (Molybdenum), $Mn$ (Manganese), and $Zn$ (Zinc) are classified as micronutrients because they are required in very small amounts.

(D) Essential elements are classified into two categories based on their quantitative requirements: macro-nutrients and micro-nutrients.
Macro-nutrients are generally present in plant tissues in large amounts (in excess of $10 \text{ mmol kg}^{-1}$ of dry matter).
These include $C, H, O, N, P, S, K, Ca,$ and $Mg$.
Micro-nutrients or trace elements are needed in very small amounts (less than $10 \text{ mmol kg}^{-1}$ of dry matter).
These include $Fe, Mn, Cu, Mo, Zn, B, Cl,$ and $Ni$.
Since $Zn$ is required in small amounts, it is classified as a micro-nutrient, not a macro-nutrient.

(D) Phosphorylation is the process of adding a phosphate group to an organic molecule,such as $ADP$ to form $ATP$. This process requires phosphorus (as phosphate) and magnesium $(Mg^{2+})$ as a cofactor for enzymes like kinases and ATPases involved in the reaction. Therefore,magnesium and phosphate are essential elements used in phosphorylation.

(B) Calcium $(Ca)$ is an essential macronutrient for plants. It is required for the formation of the middle lamella in cell walls as calcium pectate. Furthermore,calcium plays a crucial role in the development and elongation of root hairs,which are necessary for the absorption of water and minerals from the soil.

(B) Plants require micro-nutrients or trace elements in very small amounts (less than $10 \ mmol \ kg^{-1}$ of dry matter).
Among the given options,$Mg$,$Ca$,and $P$ are macro-nutrients required in larger quantities.
$Zn$ (Zinc) is a micro-nutrient required by plants only in trace amounts,and its higher concentrations are highly toxic to the plant.

(C) Copper $(Cu^{2+})$ is an essential micronutrient for plants.
It is a structural component of the protein plastocyanin,which is involved in electron transport during photosynthesis.
Additionally,copper is a functional component of several enzymes,including cytochrome oxidase,which is essential for the electron transport chain in cellular respiration.
Therefore,both $(a)$ and $(b)$ are correct.

(B) Foliar application is a technique of feeding plants by applying liquid fertilizer directly to their leaves. Among the given options,$Boron$ is a micronutrient that can be effectively absorbed by the leaves when applied as a foliar spray. While other elements like $Zinc$ and $Iron$ can also be absorbed,$Boron$ is specifically noted in agricultural practices for its high mobility and efficiency in foliar absorption to correct deficiencies.

(D) Boron is essential for the uptake and utilization of calcium by plants.
It plays a crucial role in maintaining the solubility of calcium within the cells,which is vital for cell wall formation and membrane integrity.

(C) The elements arsenic $(As)$,copper $(Cu)$,and mercury $(Hg)$ are known for their toxic effects on living organisms.
Many elements,such as copper $(Cu)$,become toxic when present in concentrations higher than the normal physiological requirement.
Other elements,such as mercury $(Hg)$ and arsenic $(As)$,are toxic even at very low concentrations,as they interfere with essential metabolic processes and enzyme functions.

(C) The correct answer is $C$. Copper $(Cu)$ is an essential micronutrient for plants,but it becomes toxic when present in higher concentrations in the soil. Specifically,a concentration exceeding $20 \mu g/g$ of dry weight of soil is considered toxic to most plants.

(C) Iron $(Fe)$ is an essential micronutrient for plants. It is a structural component of cytochromes and ferredoxin,which are involved in electron transport. In seeds,iron is often stored in the form of ferritin within the aleurone grains. Aleurone grains are proteinaceous storage bodies found in the endosperm of many seeds.

(D) The essential mineral elements are classified into two categories based on their quantitative requirements by plants:
$1$. Macro-nutrients: These are required in large amounts (e.g., $C, H, O, N, P, K, S, Ca, Mg$).
$2$. Micro-nutrients or trace elements: These are required in very small amounts (e.g., $Fe, Mn, Cu, Mo, Zn, B, Cl, Ni$).
Calcium $(Ca)$ is a macro-nutrient because it is required by plants in concentrations greater than $10 \text{ mmol kg}^{-1}$ of dry matter. Therefore, it is not a micro-nutrient.

(B) The correct answer is $B$.
Among the given options, $Nickel$ is required in the smallest quantity by plants.
While $Cobalt$, $Vanadium$, and $Nickel$ are considered beneficial elements, $Nickel$ is specifically recognized as an essential micronutrient for many plants, required in extremely low concentrations (often less than $0.1 \mu g/g$ of dry weight) for the activity of the enzyme $Urease$.

(B) Manganese $(Mn^{2+})$ is an essential micronutrient for plants. It plays a crucial role in the photolysis of water during photosynthesis,which occurs in the chloroplasts of leaves. Additionally,manganese is required for the activation of various enzymes involved in respiration and nitrogen metabolism,which are particularly active in developing seeds. Therefore,manganese ions are primarily required in the leaves and seeds of the plant.

(A) Essential elements are classified into two categories based on their quantitative requirements: macronutrients and micronutrients.
$1$. Macronutrients are generally present in plant tissues in large amounts (in excess of $10 \text{ mmol kg}^{-1}$ of dry matter).
$2$. Micronutrients or trace elements are needed in very small amounts (less than $10 \text{ mmol kg}^{-1}$ of dry matter).
$3$. Among the given options, $Nitrogen$, $Magnesium$, and $Calcium$ are macronutrients.
$4$. $Manganese$ $(Mn)$ is a micronutrient required by plants for various metabolic processes, including the photolysis of water during photosynthesis.

(A) Essential mineral elements are classified into two categories based on their quantitative requirements: macro-nutrients and micro-nutrients.
Macro-nutrients are generally present in plant tissues in large amounts (in excess of $10 \text{ mmol kg}^{-1}$ of dry matter). Examples include Carbon,Hydrogen,Oxygen,Nitrogen,Phosphorus,Sulphur,Potassium,Calcium,and Magnesium.
Micro-nutrients or trace elements are needed in very small amounts (less than $10 \text{ mmol kg}^{-1}$ of dry matter). Examples include Iron,Manganese,Copper,Molybdenum,Zinc,Boron,Chlorine,and Nickel.
Among the given options,Copper $(Cu)$ is a micro-element,while Calcium,Magnesium,and Oxygen are macro-elements.

(B) Molybdenum $(Mo)$ is an essential micronutrient for plants. It is a key component of the enzyme nitrogenase,which is involved in biological nitrogen fixation. Additionally,it acts as an essential cofactor and enzyme activator for nitrate reductase,which is responsible for the reduction of nitrate to nitrite during nitrogen metabolism in plants.

(D) Ferredoxin is an iron-sulfur protein that acts as an electron carrier in various metabolic processes,including photosynthesis and nitrogen fixation. Since it contains iron $(Fe)$ as a central component,the correct answer is $Fe$.

(D) Trace elements,also known as micronutrients,are essential mineral elements required by plants in very small amounts (less than $10 \ mmol \ kg^{-1}$ of dry matter).
Boron $(B)$,manganese $(Mn)$,copper $(Cu)$,zinc $(Zn)$,chlorine $(Cl)$,and molybdenum $(Mo)$ are all classified as micronutrients or trace elements in plant physiology.
Since all the options listed contain elements that fall under the category of trace elements,the correct answer is $D$.

(A) Boron is absorbed by plants in the form of $BO_3^{3-}$ or $B_4O_7^{2-}$ ions.
It plays a crucial role in the translocation of carbohydrates (sugars) across the plant body.
It is also involved in pollen germination,cell elongation,cell differentiation,and carbohydrate metabolism.
Therefore,the primary function listed among the options is sugar transport.

(A) Minor essential elements,also known as micronutrients,are required by plants in small amounts.
Their primary biological role is to function as co-factors for various enzymes.
They often act as metal activators that help in the catalytic activity of enzymes,thereby facilitating essential metabolic processes.

(A) $Cu$ (Copper) acts as a component of plastocyanin,which is involved in electron transport between $PS II$ and $PS I$,and in cytochrome oxidase for mitochondrial respiration.
$Mn$ (Manganese) is essential for the photolysis of water in photosynthesis and acts as an activator for many enzymes involved in respiration and photosynthesis.
$Fe$ (Iron) is a crucial component of cytochromes and ferredoxin,which are vital for electron transfer in both photosynthetic and mitochondrial electron transport chains.
Therefore,the group $Cu, Mn, Fe$ is most critical for these processes.

(D) The correct answer is $(d)$. An excess supply of Nitrogen in the soil leads to rapid vegetative growth,which makes the plant tissues succulent and more susceptible to attacks by pathogens such as fungi and bacteria.

(D) The deficiency of $Nitrogen$ causes chlorosis in the leaves of plants.
It also inhibits cell division and cell elongation,which leads to stunted growth (dwarfism) in plants.
Consequently,the production of flowers,fruits,and seeds is significantly decreased.

(D) Nitrogen is a vital element for living organisms.
It is a fundamental constituent of amino acids,which are the building blocks of proteins.
It is also a key component of nitrogenous bases found in nucleic acids ($DNA$ and $RNA$).
Furthermore,nitrogen is present in the porphyrin ring structure of chlorophyll,which is essential for photosynthesis.
Therefore,all the given options are correct.

(D) Nitrogen is absolutely essential for the synthesis of protein.
Nitrogen is a major component of amino acids,which are the building blocks of proteins.
Additionally,nitrogen is found in important molecules such as purines,pyrimidines,$RNA$,and $DNA$,all of which are critical for the process of protein synthesis.

(D) Calcium acts as a cofactor or activator for several enzymes,including $ATPase$,various kinases,and succinic dehydrogenase.
It plays a crucial role in the development of the stem and root apex.
Therefore,it is involved in the processes related to all the options provided.

(D) Sodium $(Na^+)$ is an essential mineral element required by some plants,especially $C_4$ plants and halophytes,for their growth and metabolism.
Among the given options,the desert shrub $Atriplex$ (a halophyte) specifically requires sodium for its growth and development.
Therefore,the correct option is $D$.