Role of Macro and Micro-nutrients Questions in English

(D) The correct matching is as follows:
$(a)$ Iron: Required for chlorophyll biosynthesis $(iii)$.
$(b)$ Zinc: Required for $IAA$ (Indole$-3-$acetic acid) biosynthesis $(iv)$.
$(c)$ Boron: Essential for pollen germination $(ii)$.
$(d)$ Manganese: Essential for the photolysis of water during photosynthesis $(i)$.
Therefore,the correct sequence is $(a-iii, b-iv, c-ii, d-i)$,which corresponds to option $(D)$.

(C) The correct matching is as follows:
$(a)$ Iron $(Fe)$: It is essential for the formation of chlorophyll and is a component of ferredoxin and cytochromes. Thus,$(a)-(iii)$.
$(b)$ Zinc $(Zn)$: It is required for the synthesis of auxin ($IAA$ - Indole$-3-$acetic acid). Thus,$(b)-(iv)$.
$(c)$ Boron $(B)$: It plays a crucial role in pollen germination,tube growth,and carbohydrate translocation. Thus,$(c)-(ii)$.
$(d)$ Manganese $(Mn)$: It is involved in the photolysis of water during photosynthesis. Thus,$(d)-(i)$.
Therefore,the correct sequence is $(a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)$.

(B) Magnesium $(Mg^{2+})$ ions play a crucial role in maintaining the structural integrity of ribosomes.
They help in the association of the two ribosomal subunits ($60S$ and $40S$ in eukaryotes,or $50S$ and $30S$ in prokaryotes) to form a functional $80S$ or $70S$ ribosome,respectively.

(C) $Mn$ stands for manganese.
Microelements (or trace elements) are required by plants in very small amounts (less than $10 \text{ mmol kg}^{-1}$ of dry matter).
$Ca$ (calcium), $Mg$ (magnesium), and $S$ (sulfur) are macronutrients, whereas $Mn$ (manganese) is a micronutrient.

(A) Micronutrients are essential elements required by plants in very small amounts (less than $10 \ mmol \ kg^{-1}$ of dry matter).
These elements are crucial for various physiological and metabolic processes in plants.
The essential micronutrients include Iron $(Fe)$,Manganese $(Mn)$,Zinc $(Zn)$,Boron $(B)$,Copper $(Cu)$,Molybdenum $(Mo)$,Chlorine $(Cl)$,and Nickel $(Ni)$.
Therefore,the group $Mn, Zn, Fe, B, Cl, Ni$ represents micronutrients.

(A) Both macronutrients and micronutrients are essential for plant growth and development.
They are equally important for the plant's metabolic processes.
The distinction between them is based solely on the quantity required by the plant.
Macronutrients are required in large amounts (generally $ > 10 \text{ mmol kg}^{-1}$ of dry matter), while micronutrients are required in very small amounts (generally $ < 10 \text{ mmol kg}^{-1}$ of dry matter).

(B) $ATP$ stands for Adenosine Triphosphate.
It is the primary energy currency of the cell.
The chemical structure of $ATP$ consists of an adenine base,a ribose sugar,and three phosphate groups.
Therefore,phosphorus is an essential component of $ATP$.
Essential elements are categorized based on their functions:
$(i)$ Structural components of biomolecules (e.g.,$C, H, O, N$).
$(ii)$ Components of energy-related chemical compounds (e.g.,phosphorus in $ATP$).
$(iii)$ Elements that activate or inhibit enzymes (e.g.,$Mg^{2+}$).
$(iv)$ Elements that alter the osmotic potential of a cell (e.g.,$K^+$).

(D) Essential elements required by plants in small amounts (less than $10 \ mmol \ kg^{-1}$ of dry matter) are known as micronutrients or trace elements.
These include Iron $(Fe)$,Manganese $(Mn)$,Copper $(Cu)$,Molybdenum $(Mo)$,Zinc $(Zn)$,Boron $(B)$,Chlorine $(Cl)$,and Nickel $(Ni)$.
Potassium $(K)$ is a macronutrient because it is required in large quantities for plant growth and development.
Therefore,$K$ is not a trace element.

(B) The minerals responsible for maintaining the cation-anion balance in plant cells are $Cl^{-}$ (chloride ion) and $K^{+}$ (potassium ion).
$1$. Function of $Cl^{-}$: It is essential for the photolysis of water during photosynthesis and plays a crucial role in maintaining the solute concentration and ionic balance within the cell.
$2$. Function of $K^{+}$: Potassium is vital for regulating the opening and closing of stomata by altering the osmotic potential of guard cells. Together with $Cl^{-}$,it helps in maintaining the electrochemical gradient and ionic balance across cell membranes.

(C) Plants obtain sulphur primarily in the form of sulphate $(SO_4^{2-})$.
Sulphur is a structural component of two essential amino acids: cysteine and methionine.
Additionally,it is a key constituent of several coenzymes,vitamins (such as thiamine,biotin,and coenzyme $A$),and ferredoxin.

(D) Iron $(Fe)$ plays several critical roles in plants:
$1$. It is an important constituent of cytochromes and ferredoxin,which are involved in electron transport.
$2$. It acts as an activator for the enzyme catalase.
$3$. It is essential for the biosynthesis of chlorophyll.
Since all three statements are correct,the correct option is $D$.

(A) Essential elements are components of energy-related chemical compounds in plants.
Magnesium $(Mg^{2+})$ is a central component of the chlorophyll molecule, which is essential for photosynthesis.
Phosphorus $(P)$ is a component of energy-rich compounds like $ATP$ $(Adenosine Triphosphate)$.
Since the question specifically mentions chlorophyll, the correct element is Magnesium.

(B) $Fe$ (Iron) is an essential component of proteins involved in electron transfer,such as ferredoxin and cytochromes. It undergoes reversible oxidation from $Fe^{2+}$ to $Fe^{3+}$ during electron transport.
$Cu$ (Copper) is essential for overall plant metabolism. Similar to iron,it is associated with specific enzymes involved in redox reactions and is reversibly oxidized from $Cu^+$ to $Cu^{2+}$.

(C) Plants growing near nuclear test sites are known to absorb and accumulate radioactive isotopes from the soil. Specifically,radioactive $Strontium-90$ is a common byproduct of nuclear testing that is taken up by plants because it chemically mimics calcium. While some other plants are known as hyperaccumulators for elements like gold or selenium,in the context of nuclear test sites,the accumulation of radioactive strontium is the most significant biological concern.

(B) The correct answer is $Fe$ (Iron).
$Fe$ plays several critical roles in plants:
$1.$ It acts as an activator for the enzyme catalase.
$2.$ It is a vital constituent of cytochromes,which are heme-containing proteins.
$3.$ It is an essential component of proteins involved in the Electron Transport System $(ETS)$,such as ferredoxin and cytochromes.
$4.$ It is required for the biosynthesis of chlorophyll,even though it is not a structural component of the chlorophyll molecule itself.

(B) Magnesium $(Mg^{2+})$ acts as an activator for several enzymes involved in respiration and photosynthesis,and it is also essential for the synthesis of $DNA$ and $RNA$. Manganese $(Mn^{2+})$ is another essential mineral that activates many enzymes involved in photosynthesis,respiration,and nitrogen metabolism.

(B) Essential nutrients are those required by plants for their metabolic processes and growth.
Boron,Molybdenum,and Zinc are classified as essential micro-nutrients.
Nickel is considered an essential micro-nutrient for some plants (like urease activity),but Cadmium is a toxic heavy metal and is not required for plant growth.
Therefore,Nickel and Cadmium are not considered essential micro-nutrients in the context of standard plant physiology.

(D) One of the major functions of $Ca^{2+}$ (calcium ion) is to increase the hardness of the cell wall,specifically by forming calcium pectate in the middle lamella.
Other important functions include:
$(i)$ Organization of the mitotic spindle during cell division.
$(ii)$ Regulation of meristematic activity.
$(iii)$ Involvement in metabolic processes.
$(iv)$ Prevention of mineral and organic acid toxicity.
$(v)$ Acting as a secondary messenger for various hormonal signals.

(B) The correct matches are as follows:
- $(A)$ Water splitting reaction: This process requires $Cl^-$ ions (along with $Mn^{2+}$) for the photolysis of water during photosynthesis.
- $(B)$ Uptake and utilisation of $Ca^{2+}$: Boron is essential for the uptake and utilization of calcium ions.
- $(C)$ Synthesis of auxin: Zinc is required for the synthesis of the plant growth hormone auxin (indole$-3-$acetic acid).
- $(D)$ Redox reaction: Copper is involved in various redox reactions, particularly in the electron transport chain (e.g., plastocyanin).
Therefore, the correct sequence is $A \rightarrow 3, B \rightarrow 1, C \rightarrow 4, D \rightarrow 2$.

(D) Potassium is absorbed by plants in the form of $K^+$ ions.
It is an essential macronutrient required in large quantities for various physiological processes.
Potassium is highly mobile and is required in abundant quantities in metabolically active regions of the plant,such as meristematic tissues,buds,leaves,and root tips.
Therefore,all the listed regions require potassium for growth and development.

(A) The elements $Cu$ (Copper),$Mn$ (Manganese),and $Fe$ (Iron) are essential components of various electron transport chain complexes.
$Fe$ is a critical component of cytochromes and ferredoxin,which are involved in both photosynthetic and mitochondrial electron transport.
$Cu$ is a component of plastocyanin in photosynthesis and cytochrome $c$ oxidase in the mitochondrial electron transport chain.
$Mn$ is essential for the water-splitting complex in photosystem $II$ during photosynthesis and acts as a cofactor for several enzymes in respiration.
Therefore,the deficiency of these three elements significantly impacts both photosynthetic and mitochondrial electron transport processes.

(A) $I.$ True: Magnesium is a central constituent of the chlorophyll molecule and is also involved in maintaining the structure of ribosomes.
$II.$ True: Calcium is required for the formation of the mitotic spindle during cell division.
$III.$ False: Manganese and Chloride ions are essential for the photolysis of water,not Magnesium.
$IV.$ False: Boron is involved in sugar translocation,whereas Zinc is primarily required for the synthesis of auxin.

(D) The prominent symptom of manganese toxicity is the appearance of brown spots surrounded by chlorotic veins.
It is important to know that manganese competes with iron and magnesium for uptake by plants and with magnesium for binding with enzymes.
Manganese also inhibits calcium translocation in the shoot apex.
Therefore,an excess of manganese may induce deficiencies of iron,magnesium,and calcium.

(D) $Mg^{2+}$ (Magnesium ion) acts as an essential cofactor or activator for several key enzymes involved in photosynthesis.
Specifically,it activates:
$1.$ Ribulose bisphosphate carboxylase oxygenase (RuBisCO),which is the primary enzyme for carbon fixation in the Calvin cycle.
$2.$ Phosphoenol pyruvate carboxylase (PEPCase),which is the primary enzyme for carbon fixation in $C_4$ plants.
Therefore,both $III$ and $IV$ are correct.

(D) Plants require $17$ essential elements for their growth and development.
These are classified into macronutrients and micronutrients based on their quantitative requirements.
Macronutrients are present in plant tissues in large amounts (in excess of $10 \text{ mmol kg}^{-1}$ of dry matter).
These include Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulphur, Potassium, Calcium, and Magnesium.
Manganese, Zinc, and Iron are classified as micronutrients because they are required in very small amounts.
Therefore, Magnesium is a macronutrient.

(C) Plants require nutrients in large quantities known as macronutrients,which include Carbon,Hydrogen,Oxygen,Nitrogen,Phosphorus,Sulphur,Potassium,Calcium,and Magnesium.
Iron is required by plants in small amounts,hence it is classified as a micronutrient.
Therefore,Iron is the odd one out.

(C) Micronutrients are required in small amounts (less than $10 \ mmol \ kg^{-1}$ of dry matter).
They are often involved in the activation of enzymes and can become toxic if present in excess.
However,they are not involved in building protoplasmic constituents.
Protoplasmic elements (such as $C, H, O, N, P, S$) are required in larger quantities (macronutrients) to form the structural components of protoplasm.

(D) Trace elements,also known as micronutrients,are required in very small amounts by plants and animals.
Their primary biological role is to serve as cofactors for enzymes,which are essential for catalyzing various biochemical reactions.
$N$ (Nitrogen) is a major constituent of amino acids and hormones.
$Mg$ (Magnesium) is a central constituent of the chlorophyll molecule.

(D) $Mn$ is essential for the photolysis of water during photosynthesis.
$Ca$ is required for the formation of calcium pectate in the middle lamella.
$P$ is a vital component of $ATP$, nucleic acids, and cell membranes.
$Zn$ is involved in the activation of enzymes like alcohol dehydrogenase and carboxylases, whereas Sulphur $(S)$ is a constituent of coenzyme $A$, vitamins (thiamine, biotin), and ferredoxin.
Therefore, the match "$Zn$ - Constituent of coenzyme $A$" is incorrect.

(A) Elements that are mobile in plants can be translocated from older,senescing tissues to younger,developing tissues.
$N$,$P$,and $K$ are considered highly mobile elements in plants.
Therefore,the group containing $N, P, K$ represents mobile elements.

(A) The anion-cation balance in plant cells is primarily maintained by essential elements such as $K^{+}$,$Cl^{-}$,$NO_{3}^{-}$,and $SO_{4}^{2-}$.
Specifically,$K^{+}$ plays a crucial role in maintaining the turgidity of guard cells and regulating the osmotic potential within the cell,which is essential for the anion-cation balance.

(C) Zinc $(Zn^{2+})$ acts as a cofactor for various enzymes.
Specifically,it activates alcohol dehydrogenase,which is an enzyme that facilitates the interconversion between alcohols and aldehydes or ketones with the reduction of $NAD^+$ to $NADH$.
It also stabilizes the binding of substrates to the enzyme.

(A) The enzyme nitrogenase,which is responsible for biological nitrogen fixation,is a $Mo-Fe$ protein.
Similarly,nitrate reductase,an enzyme involved in the reduction of nitrate to nitrite in plants,also requires molybdenum $(Mo)$ as a crucial cofactor for its activity.
Therefore,molybdenum is a common essential component for both nitrogenase and nitrate reductase enzymes.

(C) Elements that are structural components of the cell,such as $Ca$ (calcium),are immobile in plant tissues. Because they cannot be remobilized from older leaves to younger developing tissues,their deficiency symptoms first appear in the younger leaves.

(A) $Mg^{2+}$ is the essential element that activates the enzymes $Rubisco$ and $PEPCase$ (Phosphoenolpyruvate carboxylase).
$(1)$ $Mg^{2+}$ is also required for the activity of pyruvic acid decarboxylase,where it is present in the active site. This enzyme catalyzes the decarboxylation of pyruvic acid into acetaldehyde and $CO_2$.
$(2)$ $Mn^{2+}$ is essential for water-splitting reactions in photosynthesis.
$(3)$ Boron $(B)$ is involved in the translocation of carbohydrates.
$(4)$ Magnesium $(Mg)$ is a constituent of the chlorophyll ring structure,not the phytol tail.

(D) Potassium $(K^+)$ plays a crucial role in maintaining the anion-cation balance in cells,regulating the turgidity of cells,and controlling the opening and closing of stomata.
Auxin synthesis is primarily facilitated by Zinc $(Zn)$.
Therefore,the synthesis of auxins is not a physiological role of potassium.

(C) Nickel $(Ni)$ is an essential micronutrient that acts as a cofactor for the enzyme urease.
Urease is responsible for the hydrolysis of urea into ammonia and carbon dioxide,which is a critical step in nitrogen metabolism in plants and various microorganisms.

(A) Cytochromes are iron-containing hemoproteins that act as electron carriers in the electron transport chain. The central metal ion in the heme group of cytochromes is iron $(Fe)$, which undergoes reversible oxidation and reduction $(Fe^{2+} \leftrightarrow Fe^{3+})$ during electron transfer. Therefore, iron is an essential constituent of cytochromes.

(C) Boron is essential for the translocation of carbohydrates through the phloem.
Potassium is primarily involved in photosynthesis and the activation of various enzymes in respiration.
Molybdenum $(Mo)$ is a key component for nitrogen metabolism.

(B) Both $Cu$ (Copper) and $Fe$ (Iron) are essential micronutrients involved in electron transport chains.
$Fe$ is a key component of cytochromes and iron-sulfur proteins in both mitochondrial respiration and photosynthetic electron transport.
$Cu$ is a component of plastocyanin in photosynthesis and cytochrome $c$ oxidase (complex $IV$) in mitochondrial respiration,where it undergoes redox reactions $(Cu^+ \leftrightarrow Cu^{2+})$.

(B) Macronutrients are required in large amounts by plants. They are involved in the formation of plant structures (e.g.,$C, H, O, N$),development of osmotic potential (e.g.,$K^+$),and some play a role in electron transfer (e.g.,$Mg^{2+}$ in chlorophyll). Micronutrients,not macronutrients,are the ones that usually become toxic when present in excess amounts. Therefore,the statement that macronutrients usually become toxic in excess is incorrect.

(D) Micronutrients are required in small amounts by plants.
Excess of micronutrients can lead to toxicity,which interferes with the uptake of other essential elements.
They have a very limited role in the formation of protoplasmic structures compared to macronutrients.
Therefore,both statements $(A)$ and $(B)$ are correct.

(B) Minerals like $Fe$ (Iron),$Cu$ (Copper),$Zn$ (Zinc),$Ni$ (Nickel),and $Mo$ (Molybdenum) are essential components of various enzymes and proteins involved in redox reactions.
Specifically,$Fe$ is a component of ferredoxin and cytochromes,while $Cu$ is a component of plastocyanin,both of which are critical for electron transport in photosynthesis and respiration.
Therefore,among the given options,$Fe$ and $Cu$ are the primary minerals associated with redox reactions.

(A) Potassium $(K^+)$ and Chloride $(Cl^-)$ ions are essential for maintaining the cation-anion balance within the cells. Potassium acts as the primary cation,while Chloride acts as the primary anion to regulate the osmotic pressure and electrical neutrality of the cell.

(B) Elements that are actively mobilized within the plant are known as mobile elements. These include $N, P, K,$ and $Mg$.
$\rightarrow$ Because these elements are mobile,they are transported from older,mature tissues to younger,developing tissues.
$\rightarrow$ Consequently,deficiency symptoms for these elements are first observed in the older,mature parts of the plant.

(A) $Mg$ is a central constituent of the chlorophyll molecule,forming the core of the porphyrin ring. $Fe$ (Iron) is essential for the synthesis of chlorophyll,as it acts as a cofactor for enzymes involved in the biosynthetic pathway of chlorophyll.

(D) Essential elements are classified into two categories based on their quantitative requirements: macronutrients and micronutrients (trace elements).
$K$ (Potassium) is a macronutrient because it is required by plants in large amounts.
$Mn$ (Manganese),$Cu$ (Copper),and $Mo$ (Molybdenum) are micronutrients,which are required in very small amounts (trace amounts).

(A) Zinc $(Zn)$ is an essential micronutrient for plants. It is required for the synthesis of tryptophan,which is a precursor for the plant hormone auxin (indole$-3-$acetic acid). Zinc also acts as a cofactor for various enzymes,including carbonic anhydrase (a carboxylase). $A$ deficiency of zinc leads to the 'little leaf' disease,where leaves become small and deformed.

(C) Sulfur $(S)$ is an essential mineral that acts as a structural component in several important biological molecules.
It is a key constituent of amino acids like cysteine and methionine,which are essential for protein structure.
Furthermore,sulfur is present in several coenzymes and vitamins,including Coenzyme $A$ $(CoA)$,ferredoxin $(Fd)$,thiamine (Vitamin $B_1$),biotin,and lipoic acid.
Therefore,the correct answer is $S$.

(A) Plants require both Nitrogen $(N)$ and Phosphorus $(P)$ for the formation of $ATP$. Phosphorus is a key component of the $ATP$ molecule (Adenosine Triphosphate),while Nitrogen is an essential structural component of the adenine base and the amino acids that form the enzymes involved in energy metabolism.