Role of Macro and Micro-nutrients Questions in English

(N/A) Excess manganese $(Mn)$ in the soil interferes with the uptake and translocation of other mineral nutrients due to competitive inhibition and physiological antagonism.
$(i)$ $Mn$ competes with $Fe$ and $Mg$ for uptake by the plant roots,thereby reducing their absorption.
$(ii)$ $Mn$ inhibits the translocation of $Ca$ to the shoot apex,leading to localized deficiency symptoms.
$(iii)$ Consequently,symptoms of $Fe, Mg,$ and $Ca$ deficiency appear in the plant,such as chlorosis and stunted growth,even if these elements are present in the soil.

(D) Manganese toxicity is a condition in plants caused by an excess of manganese,characterized by the following effects:
$1$. The appearance of brown spots surrounded by chlorotic veins.
$2$. Manganese competes with iron and magnesium for uptake and binding with enzymes.
$3$. Manganese inhibits calcium translocation to the shoot apex.
$4$. Consequently,an excess of manganese may induce deficiencies of iron,magnesium,and calcium.
Thus,the symptoms observed as manganese toxicity are often the deficiency symptoms of iron,magnesium,and calcium.

(A) The correct matches are as follows:
$(a)$ Manganese: Functions in the splitting of water during photosynthesis (photolysis of water) - $(iv)$.
$(b)$ Magnesium: Activates enzymes of respiration and photosynthesis,and is a constituent of chlorophyll - $(iii)$.
$(c)$ Boron: Required for pollen germination,cell elongation,and carbohydrate translocation - $(ii)$.
$(d)$ Iron: Activates the enzyme catalase and is essential for the formation of chlorophyll - $(i)$.
Therefore,the correct matching is $(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)$.

(D) Plant nutrients are classified into two categories based on their quantitative requirements: macronutrients and micronutrients.
Macronutrients are required in large amounts (usually $ > 10 \text{ mmol kg}^{-1}$ of dry matter). These include Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur, Potassium, Calcium, and Magnesium.
Micronutrients are required in very small amounts (usually $ < 10 \text{ mmol kg}^{-1}$ of dry matter). These include Iron, Manganese, Copper, Molybdenum, Zinc, Boron, Chlorine, and Nickel.
Chlorine is classified as a micronutrient, whereas Nitrogen, Sulfur, and Calcium are macronutrients.

(B) The correct matching is as follows:
$P$. Structural elements: These are the building blocks of biological molecules. $C, H, O, N$ are the primary structural elements.
$Q$. Energy-related chemical components: Phosphorus is a component of $ATP$, and Magnesium is a component of chlorophyll. Thus, $Q-IV$.
$R$. Elements involved in enzyme activation or inhibition: $Zn^{+2}$ activates alcohol dehydrogenase, $Mo$ activates nitrogenase, and $Mg^{+2}$ activates many kinases. Thus, $R-II$.
$S$. Elements involved in osmotic potential: Potassium $(K^+)$ plays a major role in maintaining the osmotic potential of cells, particularly in stomatal opening and closing. Thus, $S-III$.
Therefore, the correct sequence is $(P-I), (Q-IV), (R-II), (S-III)$.

(A) $Mg^{2+}$ acts as an activator for several enzymes involved in photosynthesis,specifically Rubisco and $PEPcase$.
$Zn^{2+}$ is a cofactor for the enzyme alcohol dehydrogenase.
$Mo$ (Molybdenum) is a critical component of the enzyme nitrogenase,which is involved in biological nitrogen fixation.
Therefore,the correct matching is $P-I, Q-II, R-III$.

(C) Potassium $(K^+)$ is the most abundant cation in the cytoplasm. It plays a crucial role in maintaining the turgidity of cells by regulating the osmotic potential of the cell sap. It is also involved in the opening and closing of stomata,which is directly linked to the turgor pressure of guard cells.

(B) Sulfur is an essential mineral element for plants. It is found in two amino acids,cysteine and methionine,and is the main constituent of several coenzymes,vitamins (thiamine,biotin),and ferredoxin. Therefore,the correct option is $B$.

(D) The middle lamella is a layer that cements the cell walls of two adjoining plant cells together.
It is primarily composed of calcium pectate and magnesium pectate.
Calcium is essential for the formation of the middle lamella during cell division,as it acts as a binding agent in the form of calcium pectate.
Therefore,the correct option is $D$.

(D) In plants,ionic balance is crucial for maintaining the electrochemical gradient and osmotic potential.
$K^{+}$ is the most abundant cation and plays a vital role in maintaining the turgor pressure and ionic balance in cells.
$Cl^{-}$ is essential for the water-splitting reaction of photosynthesis and also contributes to maintaining the electrical neutrality of cells.
$Na^{+}$ is involved in the maintenance of membrane potential and osmotic balance in many plant species.
Therefore,all these ions contribute to the ionic balance of the plant system.

(C) Redox reactions involve the transfer of electrons.
$1$. Iron $(Fe)$ is a component of ferredoxin and cytochromes,which are essential for electron transport in photosynthesis and respiration.
$2$. Molybdenum $(Mo)$ is a component of nitrogenase and nitrate reductase,which are involved in redox reactions.
$3$. Copper $(Cu)$ is a component of plastocyanin,which acts as an electron carrier in the electron transport chain.
Chlorine $(Cl)$ is primarily involved in the water-splitting reaction of photosynthesis (photolysis) and maintaining osmotic balance,not directly in redox electron transfer chains.
Magnesium $(Mg)$ is involved in the activation of enzymes and is a central component of chlorophyll,but it does not participate in redox reactions.
Therefore,Iron,Molybdenum,and Copper are associated with redox reactions.
The total count is $3$.

(A) Sulfur is a crucial macronutrient for plants. It is a key component of the amino acids cysteine and methionine,which are essential for protein synthesis. Additionally,sulfur is found in several coenzymes,vitamins (like thiamine,biotin,and coenzyme $A$),and ferredoxin.

(C) Boron is essential for the translocation of carbohydrates in plants. It facilitates the movement of sugars across cell membranes by forming sugar-borate complexes. Therefore,option $C$ is the correct answer.

(D) Calcium $(Ca^{2+})$ is absorbed from the soil as calcium ions. It is required by meristematic and differentiating tissues. During cell division,it is used in the synthesis of the cell wall,particularly as calcium pectate in the middle lamella. It also plays a role in the regulation of metabolic activities. However,the opening and closing of stomata is primarily regulated by potassium $(K^+)$ ions,not calcium. Therefore,the statement regarding stomatal movement is incorrect.

(A) Elements that are actively mobilized within the plants are exported to young developing tissues.
$Nitrogen$,$Potassium$,and $Magnesium$ are highly mobile elements.
$Calcium$ is a structural component of the cell wall (as calcium pectate) and is not remobilized once it is incorporated into the plant tissues.
Therefore,deficiency symptoms of $Calcium$ appear first in the young tissues.

(B) Manganese $(Mn^{2+})$ plays a critical role in the photolysis of water,which is the splitting of water molecules to release oxygen,electrons,and protons during the light-dependent reactions of photosynthesis.
Copper $(Cu)$ is essential for electron transport in the chloroplasts and overall plant metabolism.
Molybdenum $(Mo)$ is primarily involved in nitrogen metabolism,specifically in the enzyme nitrogenase and nitrate reductase.
Magnesium $(Mg)$ is a structural component of the chlorophyll molecule and acts as an activator for several enzymes involved in photosynthesis and respiration.

(D) Iron $(Fe)$ acts as an activator for the enzyme catalase.
Zinc $(Zn)$ is essential for the synthesis of the plant hormone auxin.
Boron $(B)$ plays a crucial role in cell elongation and cell differentiation.
Molybdenum $(Mo)$ is a vital component of enzymes like nitrogenase and nitrate reductase.
Matching these: $A-III, B-I, C-IV, D-II$.
Therefore, the correct option is $D$.

(C) Microelements (also known as trace elements) are required in very small amounts by plants.
From the given list,the microelements are: $Zn$ (Zinc),$Cu$ (Copper),$Mn$ (Manganese),$Mo$ (Molybdenum),and $Fe$ (Iron).
Note: $Al$ (Aluminum) is not an essential plant nutrient.
Therefore,the microelements are $Zn, Cu, Mn, Mo, Fe$.
The total count is $5$.

(C) Microelements (micronutrients) are required in very small amounts by plants.
They primarily function as co-factors for enzymes,which means they play a catalytic role in various metabolic processes,including the synthesis of organic food.
Examples of such microelements include $Zn$,$Cu$,$Mn$,$B$,$Mo$,and $Cl$.

(C) Plant nutrients are classified into two categories based on their quantitative requirements: macronutrients and micronutrients.
$1$. Macronutrients are required in large amounts (usually $10 \ mmol \ kg^{-1}$ of dry matter or more).
$2$. Micronutrients or trace elements are required in very small amounts (less than $10 \ mmol \ kg^{-1}$ of dry matter).
$Mg$ (Magnesium) is a macronutrient because it is a constituent of the chlorophyll molecule and is involved in the activation of many enzymes.
$Cu$ (Copper),$Mn$ (Manganese),and $Cl$ (Chlorine) are all essential micronutrients required by plants in small quantities.
Therefore,$Mg$ is the correct answer as it is not a micronutrient.