Plant Pathology - Study Mode
[#246] Match the following columns: Column I (Fertilisers) Column II (N- content %) a. Sodium nitrate 1. 13 b. Calcium nitrate 2. 16 c. Potassium nitrate 3. 15 d. Urea 4. 46
Correct Answer
(D) a-2, b-3, c-1, d-4
Explanation
Solution: Sodium nitrate supplies water supplying a water-soluble form of nitrogen without altering the pH of the soil. It contains 16% of nitrogen. Calcium nitrate fertilizer is a water-soluble chemical solution that provides plants with supplemental calcium and nitrogen. Its nitrogen content is about 15%. Potassium nitrate fertilizer is a water-soluble fertilizer with high potassium and nitrogen content along with an optimal amount of sodium, its nitrogen content is 13%. Urea is the most important nitrogenous fertilizer and is widely used also because of its high Nitrogen content which is about 46%.
[#247] ATP formation in chloroplast and mitochondrion is explained by
Correct Answer
(B) Chemi-osmotic theory of Mitchell
Explanation
Solution: ATP formation in chloroplast and mitochondrion is explained by the Chemi-osmotic theory of Mitchell. The chemiosmotic theory states that the transfer of electrons down an electron transport system through a series of oxidation-reduction reactions releases energy. This energy allows certain carriers in the chain to transport hydrogen ions (H + or protons) across a membrane. Mitchell's theory stated that the electron transport chain and ATP synthesis are embedded in the same membrane, that the membrane is impermeable to protons, that compounds involved in the electron transport chain and ATP synthesis are in contact with one another or the other side of the membrane, that there is an exchange of protons across the membrane, leading to the synthesis of ATP.
[#248] Total number of meiotic division required for forming 100 zygotes/100 grains of wheat is
Correct Answer
(C) 125
Explanation
Solution: The total number of meiotic divisions required for forming 100 zygotes/100 grains of wheat is 125. A zygote is formed by the combination of male and female gametes, which that means for 100 zygotes, 100 male and female gametes will be required. Male gametes are formed by the process of microsporogenesis, and in this, 1 cycle leads to the formation of 4 pollen grains. For 100 microspores, $$frac{{100}}{4}$$ = 25 cycles of meiosis will be done. Now, female gametes are formed by the process of megasporogenesis, and for each active megaspore, 1 cycle of meiotic division is required. Thus, for 100 megaspores, 100 cycles of meiosis will be done. That is ultimate, 100 + 25 = 125 meiotic division will produce 100 grains or zygotes.
[#249] Bunchy top of papaya (caused by MLO) is spread by
Correct Answer
(D) Leaf hoppers
Explanation
Solution: The bunchy top of papaya (caused by MLO) is spread by Leaf hoppers. Papaya Bunchy Top Disease was first discovered in 1931 in Puerto Rico. Bunchy Top Disease in Papaya is the most serious disease that severely limits commercial production. The disease is caused by Mycoplasma organism (MLOs) and is vectored by a leafhopper Empoasca papaya. It is vectored by two species of leafhopper, Empoasca papayae Oman (Sein) and Empoasca stevensi Young. The species that vector the disease is dependent on the geographical location.
[#250] Plants absorb nutrients mostly through
Correct Answer
(C) Roots
Explanation
Solution: Plants absorb nutrients mostly through Roots. Mineral nutrients are usually obtained from the soil through plant roots, but many factors can affect the efficiency of nutrient acquisition. During diffusion, roots grow throughout the profile and use up nutrients directly around the root system and the root hairs. As the concentration of nutrients around the root system drops, nutrients from higher concentrated areas move or diffuse toward low concentration areas and the roots.