Answer : (d)

Answer : (c)

Answer:(c)

Answer : (a)

Plants obtain iron in the form of ferric ions (Fe3+). It is reversibly oxidised from Fe2+ to Fe3+ during electron transfer. It activates catalase enzyme, and is essential for the formation of chlorophyll. a → iii Plants obtain zinc as Zn2+ ions. It activates various enzymes, especially carboxylases. It is also needed in the synthesis of auxin (IAA). b → iv Boron is absorbed as BO33- or B4 O72-. Boron is required for uptake and utilisation of Ca2+, membrane functioning, pollen germination, cell elongation, cell differentiation and carbohydrate translocation. c → ii The best defined function of manganese is in the splitting of water to liberate oxygen during photosynthesis d → i Answer : (a)

Answer:(a)

Answer : (c)

Answer : (b)

At least 17 elements are known to be essential nutrients for plants. In relatively large amounts, the soil supplies nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur; these are often called the macronutrients. ... Carbon and oxygen are absorbed from the air while other nutrients are absorbed from the soil. Answer : (c)

The nif genes are genes encoding enzymes involved in the fixation of atmospheric nitrogen. The primary enzyme encoded by the nif genes is the nitrogenase complex which is in charge of converting atmospheric nitrogen to other nitrogen forms such as ammonia, which plants can use for various purposes Answer : (a)

A mineral element is considered essential to plant growth and development if the element is involved in plant metabolic functions and the plant cannot complete its life cycle without the element. Answer : (d)

Denitrification is the name of the biochemical process whereby bacteria in soil converts nitrates (through several steps) into nitrogen gas and nitrous oxide. Pseudomonas, and Achromobacter are implicated as denitrifiers. Pseudomonas aeruginosa can, under anaerobic conditions (as in swampy or water-logged soils), reduce the amount of fixed nitrogen (as fertilizer) by up to 50 percent Answer : (d)

Plants take nitrogen from the soil by absorption through their roots as amino acids, nitrate ions, nitrite ions, or ammonium ions. Answer:(d)

Leghaemoglobin is found in the nodules of leguminous plants. The main functions of leghemoglobin are (1) to facilitate oxygen supply to the nitrogen fixing bacteria and (2) to protect the enzyme, nitrogenase from being inactivated by oxygen. Answer : (d)

Answer:(d)

Active transport mechanisms require the use of the cell's energy, usually in the form of adenosine triphosphate (ATP). Active transport is the movement of molecules across a cell membrane from a region of their lower concentration to a region of their higher concentration Answer : (a)

Denitrification is the name of the biochemical process whereby bacteria in soil converts nitrates (through several steps) into nitrogen gas and nitrous oxide. Ammonification: This is a process where bacteria or other decomposers break down nitrogen-containing chemicals from waste or a dead body into simpler chemicals, such as ammonia. Answer : (c)

99% of protoplasm is made of 4 basic elements, i.e., oxygen, carbon, hydrogen and nitrogen Therefore; these are called major constituents of the protoplasm. 8 other elements (trace elements), present in quantities of less than 1% each, are sulphur, phosphorus, potassium, iron, magnesium, calcium, sodium and chloride Proteins are made up of smaller building blocks called amino acids, have Carbon, Oxygen Nitrogen Hydrogen Answer : (b)

Mineral ions cross plasma membranes by a chemiosmotic mechanism. Plants absorb minerals in ionic form: nitrate (NO3−), phosphate (HPO4−) and potassium ions (K+); all have difficulty crossing a charged plasma membrane. Answer : (b)

Active transport is the movement of molecules across a membrane from a region of lower concentration to a region of higher concentration against the concentration gradient. Uses ATP energy “Passive transport is the movement of molecules across the membrane without the help of energy. Answer : (b)

Assertion is correct because: Symbiotic nitrogen fixation occurs in legume plants. It takes place in the Rhizobium bacteroids which are located within root nodules cells. The important enzyme Nitrogenase (synthesised by Rhizobium) that reduces N2, is oxygen sensitive. lt can only function at low oxygen concentration Reason is not correct because: Its function is to help provide oxygen to the respiring symbiotic bacterial cells. Answer : (c)

Analysis of plant ash shows that about 92 mineral elements are present in different plants Answer : (b)

Nitrifying bacteria include ammonia-oxidizing bacteria and nitrite-oxidizing bacteria Nitrifying bacteria in the soil convert ammonia into nitrite (NO2-) and then into nitrate (NO3-). This process is called nitrification. Compounds such as nitrate, nitrite, ammonia and ammonium can be taken up from soils by plants and then used in the formation of plant and animal proteins. Nitrifying bacteria are chemolithotrophic organisms that include species of the genera Nitrosomonas, Nitrosococcus, Nitrobacter and Nitrococcus. These bacteria get their energy by the oxidation of inorganic nitrogen compounds. Answer : (d)

Nitrogenase is an enzyme responsible for catalyzing nitrogen fixation, which is the reduction of nitrogen (N2) to ammonia (NH3) and a process vital to sustaining life on Earth Answer : (d)

Cu (copper), Mn (manganese) and Fe (Iron) are those micronutrients which affect both photosynthesis and mitochondrial electron transport because they are the main constituents of various electron carriers. Answer : (a)

Inorganic nutrients are present in the soil as Electrically charged ions Cations in Soil : Potassium, Ammonium,Magnesium, Calcium ,Manganese ,Zinc,Hydrogen Anions in Soil Nitrate Sulfate Phosphate Chloride Borate Molybdate Answer : (c)

Biological nitrogen fixation through Azolla Anabaena complex is a potential biological system for increasing rice yields, at comparatively low cost. Azolla possesses the desired qualities of a green manure crop, like quick growth, large biomass production, higher nitrogen content and easy decomposability in the soil. Answer : (b)

Micronutrients: boron (B), chlorine (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), and zinc (Zn). The macronutrients include: Carbon (C), Hydrogen (H), Oxygen (O),Nitrogen (N),Phosphorus (P),Potassium (K),Calcium (Ca),Magnesium (Mg),Sulfur (S) Answer : (c)

Nitrosomonas is a genus of Gram-negative rod-shaped chemoautotrophic bacteria. This organism oxidizes ammonia into nitrite as a metabolic process, known as nitritation Answer : (b)

boron deficiency can cause root crops, especially rutabaga, to develop soft brown centers, a disorder called “brown heart” Answer : (b)