Practice free Microbes and Human Welfare (Botany) NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
An organism used as a biofertilizer for raising soyabean crop is
(b) Rhizobium leguminosarum is a symbiotic bacteria found in root nodules of legume. This bacterium has nitrogen fixing gene and fixing N2. Soyabean is a legume. Thus, Rhizobium is used as a biofertilizer for raising soyabean crop.
Leghaemoglobin is produced in response to
(d) : Bacteria like Rhizobium and Frankia live free as aerobes in the soil but are unable to fix nitrogen. They develop the ability to fix nitrogen only as a symbiont when they become anaerobic. They are unable to fix nitrogen by themselves. Roots of a legume secrete chemical attractants. Bacteria collect over the root hairs and form an infection thread enclosing the bacteria. Infection thread grows alongwith multiplication of bacteria. Bacteria stop dividing and form irregular polyhedral structures called bacteroids. In an infected cell bacteriods occur in groups surrounded by host membrane. The host cell develops a pinkish pigment called leghaemoglobin (Lb). It is oxygen scavenger and is related to blood pigment haemoglobin. It protects nitrogen fixing enzyme nitrogenase from oxygen.
To obtain a virus free plant, what can be used as an explant in micropropogation ?
Page 177, XII NCERT
Meristem culture is especially important to obtain:
Read page 177, XII NCERT
Which one of the following is linked to the discovery of Bordeaux mixture as a popular fungicide?
Bordeaux mixture was discovered by Millardet in France in 1882. It is prepared by dissolving 40 g of copper sulphate and 40 g of calcium hydroxide in 5 L of water. It was first used to control downy mildew disease of grape-vine that is caused by a fungus Plasmopara viticola. Black rust of wheat is caused by Puccinia graminis tritici. The use of fungicide Dithane
Z-78 and Dithane M-45 control the disease even at lower concentration.
Loose smut of wheat is caused by Ustilago tritici. The use of fungicides (systemic fungicide like D-735 and F-461) give quite encouraging result.
Pollution from animal excreta and organic waste from kitchen can be most profitably minimized
(b) : Pollution from animal excreta and organic waste from kitchen can be most profitably minimized by using the in the generation of biogas. Biogas is a mixture of methane and carbon dioxide resulting from the anaerobic decomposition of such waste materials as domestic, industrial and agricultural sewage.
Biochemical oxygen demand is
Page number 275
16.2 Water Pollution and It's control
16.2.1 Domestic Sewage and Industrial Effluents
Environmental Issues
Higher the biodegradable organic matter in sewage
Page number 275
16.2 Water Pollution and It's control
16.2.1 Domestic Sewage and Industrial Effluents
Environmental Issues
Algal bloom is
Page number 275
16.2 Water Pollution and It's control
16.2.1 Domestic Sewage and Industrial Effluents
Environmental Issues
Which of the following statements is wrong?
Page number 275
16.2 Water Pollution and It's control
16.2.1 Domestic Sewage and Industrial Effluents
Environmental Issues
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