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The correct choice is (a) True

Explanation: HYDROPONICS is the process of growing PLANTS in ARTIFICIAL nutrient media. It is done with PURIFIED water and mineral salts which means soil is not a necessary factor for growth of PLANT. It is the minerals that plants get from the elements present in the soil which is responsible for the development of the plant body.

Correct option is (c) OLD leaves

To explain I WOULD say: The chief sinks for the mineral elements are the growing regions of the plant such as apical and lateral meristems, young leaves, developing flowers, FRUITS and SEEDS, and the storage ORGANS.

Right answer is (c) It acts as a matrix that destabilizes the plant

For explanation: Plants take their nutrition from minerals present in the soil. Many MACRO and MICRONUTRIENTS are present in the soil. The soil also harbors nitrogen fixing bacteria that fix nitrogen in order for uptake by plants. It performs SEVERAL other FUNCTIONS like holding water and supplying air to ROOT’s respiration. It also acts as a matrix for stabilization of the plant.

The CORRECT CHOICE is (c) Pseudomonas

Explanation: Pseudomonas is the ORGANISM is capable of carrying out denitrification. BEIJERNICKIA is free-living NITROGEN fixing aerobic nitrogen fixer. Nitrobacter convert nitrite to nitrate form. Nitrosomonas convert ammonia to nitrite form.

Correct option is (c) NA

The BEST explanation: Na COMES under the group of elements which are beneficial to plants if given in very small amounts. Ca, Mo and Zn are constituents of ESSENTIAL elements group which are absolutely necessary for the survival of the plants.

Correct choice is (B) Cu

Easy explanation: Cu DEFICIENCY leads to Exanthema in CITRUS. P deficiency leads to poor growth of leaves. B deficiency leads to HEART rot of beets. Zn deficiency leads to Khaira disease of RICE.

Right option is (a) True

The explanation: Nitrogen is a constituent of various substances REQUIRED by all the LIVING BEINGS. Plants compete with microbes for the uptake of limited nitrogen AVAILABLE in the soil. Nitrogen is a limiting nutrient for both agricultural and natural ECOSYSTEMS.

The correct answer is (b) They are control POINTS

The best I can explain: Transport proteins of endodermal CELLS are control points, where the plant adjusts the QUANTITY and types of solutes that REACH the XYLEM.

The correct choice is (a) JULIUS Von SACHS

To elaborate: Hydroponics is the process of growing plants in artificial nutrient media by providing the required conditions for its proper GROWTH. It was demonstrated by Julius Von Sachs in 1860. Melvin Calvin is an American biochemist who received the 1961 Nobel Prize for CHEMISTRY for his discovery of the chemical PATHWAYS of photosynthesis. The Hoagland solution developed by Hoagland and Snyder provides every nutrient necessary for plant growth and is appropriate for the growth of a large variety of plant species. It was corrected by scientist Arnon.

Right answer is (b) False

Easiest explanation: The ROOT endodermis because of the layer of suberin can actively transport IONS in one direction only. Like all the cells, the endodermal cells have many transport proteins embedded in their PLASMA MEMBRANE.

The CORRECT CHOICE is (c) Transaminase

Best explanation: Transaminase is the enzyme which catalyses the process of transamination. NITROGENASE is RESPONSIBLE for nitrogen fixation. Glutamate dehydrogenase has role in the process of reductive amination. Lipase is a LINKING enzyme and has no role to play in nitrogen metabolism.

Correct choice is (d) Frankia

The explanation: Frankia is a microbe that is capable of FIXING nitrogen in non-leguminous PLANTS such as Alnus. It also produces nodules in the roots of plant. It can freely live in soil but fixes nitrogen as a symbiont. BACILLUS is a free LIVING anaerobic nitrogen fixer. Beijernickia is an aerobic nitrogen fixer. Anabaena is a microbe AMONG the cyanobacteria that is capable of nitrogen fixation.

Right CHOICE is (c) As inorganic ions

Best EXPLANATION: NITROGEN GENERALLY travels in the plants in the form of inorganic ions, though only some PROPORTION of nitrogen is travelled in this form. Most of the nitrogen is being transported as organic compounds like the amino acids.

Right option is (c) xylem, ascending

To explain: Minerals are transported through xylem along the ascending STREAM of WATER. Phloem is used for the translocation of solutes and sometimes organic nitrogen compounds. Phloem EXHIBITS both upward and downward MOVEMENT of FOOD along with the movement of water in the adjacent cells.

Correct CHOICE is (d) Mg

To explain: Mg is ABSORBED by plants in the form of divalent. It is a constituent of structure of ribosome and acts as a binding component. Cu is involved in electron TRANSPORT chain of photosynthesis. Mn is the component of oxygen EVOLVING complex. Cl is responsible for anion-cation BALANCE in cells.

Right answer is (C) Through the transpiration stream

Easiest explanation: After the active or passive ABSORPTION of all the mineral ELEMENTS, minerals are further transported through the transpiration stream. Transpiration pull is the main mineral transporting force ACROSS the entire parts of the plants.

Right option is (c) xylem vessels

The EXPLANATION is: Amides CONTAIN more nitrogen than amino acids. They are transported to other parts of the plant through xylem vessels. Phloem TISSUE has no function in relation to TRANSLOCATION of amides.

The correct choice is (d) Zn

The best I can explain: Deficiency of Zn leads to rosette growth of plant. P is PRESENT in cell membranes. Mo PARTICIPATES in NITROGEN metabolism. B is RESPONSIBLE for carbohydrate translocation.

The correct answer is (a) They are present in the SOIL as CHARGED particles

For explanation: Unlike water, all MINERALS cannot be passively absorbed by the roots because the minerals are present in the soil as charged particles which cannot move ACROSS the CELL membranes. Also, the concentration of the minerals in the soil is usually lower than the concentration of minerals in the roots.

Right answer is (c) FE

To explain I would say: Fe is an essential element belonging to the group of micronutrients. Micronutrients consist of ELEMENTS which are NECESSARY for plant’s survival and are required in less than 10 mmole Kg^-1. NA, CO and Si are beneficial elements required in very small amounts and are present in only few varieties of plants.

Right ANSWER is (a) True

Explanation: The bacteria enter the plant body through root hair with the help of formation of an infection thread. After entering INSIDE the cell, the bacteria change its FORM to rod-shaped BACTERIUM in order to initiate division of inner cortical and pericycle cells.

The CORRECT option is (d) industrial N2 fixation

Explanation: In industrial N2 fixation, nitrogen and hydrogen combine to form AMMONIA under high temperature and pressure conditions. Electrical N2 fixation is carried out by lightening process. Biological N2 fixation is taken up by CERTAIN prokaryotic bacteria. NATURAL N2 fixation is not known yet.

Right CHOICE is (a) TRUE

Best EXPLANATION: It is true that a small amount of exchange of materials does take place between XYLEM and phloem because these tissues are not completely isolated from each other. Therefore, it is possible for xylem to carry organic materials while the phloem to carry inorganic nutrients.

The CORRECT option is (b) Sucrose

Easiest explanation: Food, PRIMARILY sucrose, is transported by the vascular tissue phloem from a SOURCE to a sink. Food in phloem sap can be transported in any REQUIRED DIRECTION.

Right choice is (a) Bi-directional

The best I can explain: The direction of food in PHLOEM is bi-directional as the LEAVES which synthesise food NEED to transport the organic materials or the food to the shoot as well to the root apex which LIE in the opposite DIRECTIONS.

Right option is (C) Through Active absorption

The explanation is: Most minerals enter the root by active absorption into the CYTOPLASM of epidermal CELLS. This needs energy in the FORM of ATP. Some ions ALSO move into the epidermal cells passively.

Right option is (a) The part that needs the food

To explain I would SAY: Usually the source is UNDERSTOOD to be that part of the PLANT which synthesises the food, i.e., the leaf, and SINK, the part that needs or stores the food. But, the source and the sink may be REVERSED depending on the season or on the plant’s needs.

Correct choice is (b) toxic concentration

To elaborate: Toxic concentration is the concentration that reduces the dry WT. of tissues by 10 PERCENT. Critical concentration is the concentration below which the growth of plant starts to retard. BENEFICIAL concentration is the concentration which is favorable for higher growth of plant. Optimum concentration is the concentration which should be MAINTAINED for stable growth of plant.

Right choice is (b) Ocean

The explanation is: Oceans are not reservoir for NITROGEN CYCLE. They contain nitrogen in FORM of deposits. ATMOSPHERE, soil and biomass act as pools for nitrogen cycle and there is exchange of nitrogen AMONG them from one form to another.

The correct choice is (a) N2

For explanation: N2 is the FORM of nitrogen which exists in the ATMOSPHERIC but is unavailable and is not useful for the plants. It has to be converted to other molecular forms by different nitrogen fixation processes in ORDER to be accessible to plants. Plants mostly take up nitrogen in form of NO3^–. Also, SOMETIMES they absorb nitrogen in NO2^– and NH4^+ forms.

The CORRECT CHOICE is (d) B

For explanation I would say: Boron is a micronutrient. Micronutrients consist of elements required in less than 10 mmole Kg^-1. C, H and S come under the category of macronutrients. Macronutrients consist of elements required in EXCESS of 10 mmole Kg^-1.

Correct answer is (b) False

The explanation is: ZINC is required for the synthesis of AUXIN HORMONE. Zinc is absorbed in FORM of divalent form. It activates various enzymes such as alcohol dehydrogenase and carboxylases. Deficiency SYMPTOMS.

Correct CHOICE is (B) False

Best explanation: The enzymes for nitrogen FIXATION are found exclusively in prokaryotes. Rhizobium bacterium is known for its symbiotic relationship with roots of LEGUMES. Rhodospirillum, Bacillus, AZOTOBACTER are other bacteria having nitrogen fixing capability.

Correct ANSWER is (b) Biotin

Best EXPLANATION: Biotin is the sulphur-containing VITAMIN. ASCORBIC acid is vitamin C. Retinol is vitamin A. COBALAMIN is vitamin B12.

The correct choice is (d) Mg

For explanation I would say: Mg is a macronutrient. Macronutrients consist of elements which are necessary for plant’s survival and are required in excess of 10 MMOLE Kg^-1. Mg is ABSORBED by plants in DIVALENT form. It is involved in the synthesis of DNA & RNA. Cu, Mn and Cl are micronutrients.

Correct option is (d) Ca

The best explanation: Elements such as N, P and K get readily mobilized from older PARTS to younger ones before the death of the plant or before new growth appears. Ca, being a PART of the STRUCTURE of the cell WALL and middle lamella does not move to the younger parts.

Correct choice is (a) Mn

To explain: Mn DEFICIENCY that leads to grey SPECK of oats. Zn deficiency leads to SICKLE disease of cocoa. B deficiency leads to brown heart of turnip. Mo deficiency leads to whiptail of CAULIFLOWER.

Correct option is (C) Pollen germination

For explanation: Chlorine is an essential micronutrient. It is absorbed by PLANTS in FORM of Cl-. Its functions include maintaining anion-cation balance of cell, determination of solute concentration in cell and oxygen EVOLUTION in water splitting reaction. Boron is responsible for pollen germination.

The correct choice is (d) From carbon dioxide in the ATMOSPHERE

To explain: Plants obtain most of their carbon and most of their oxygen from CO2 in the atmosphere. However, their REMAINING NUTRITIONAL requirements are obtained from water and minerals in the soil.

Right choice is (d) Pumpkin

To explain: HYDROPONICS is the process of growing plants in artificial nutrient media. Tomato, Lettuce and Seedless cucumber are grown commercially by the process of hydroponics. Pumpkin and other melons are not grown hydroponically. These plants require a lot of SPACE to grow as they spread and INCREASE in size. Also, pollination is difficult as they need bees to pollinate them. So, hydroponics of these vegetables BECOMES highly LABOR intensive.

The CORRECT choice is (c) Fe

To elaborate: Fe is the element that activates ENZYME catalase. Plants obtain iron in the form of ferric ions. Na is responsible for C4 metabolism. Co is essential for nitrogen fixation by the nitrogen-fixing bacteria associated with legumes and other plants. Si improves the health of plants.

The correct OPTION is (a) NO2^–

To elaborate: Plants absorb nitrogen in form of NO2^– and NO3^–. N2O and NO are OBTAINED from electrical N2 FIXATION. NH3 is the first STABLE product.

Correct answer is (b) False

Explanation: Leg-haemoglobin is a PIGMENT present in root NODULES of leguminous plants. It acts as oxygen scavenger. It PROTECTS NITROGENASE enzyme from aerobic conditions as it is highly SENSITIVE to molecular oxygen.

The correct answer is (a) Ni

Easiest explanation: Ni is the MICRONUTRIENT is used in metabolism of urea and UREIDES. Mo participates in nitrogen metabolism. Cu is involved in electron TRANSPORT chain of PHOTOSYNTHESIS. MN is the component of oxygen evolving complex.