An organism used as a biofertilizer for raising soyabean crops is

Azotobacter
Azospirillum
Rhizobium
Nostoc

Solution

Rhizobium is a nitrogen fixing bacteria, which acts as a biofertilizer in soil to produce soyabean crops.

The common nitrogen fixer in paddy fields is

Rhizobium
Azospirillum
Oscillatoria
Frankia

Solution

The common nitrogen fixer in paddy field is Azospirillum. It is an anaerobic bacteria that forms loose association with roots of paddy crops.

The aquatic fern, which is an excellent biofertiliser is

Azolla
Salvinia
Marsilia
Pteridium

Solution

Azolla is a freshwater fern harbouring a bluegreen alga - Anabaena in its leaf cavities. The alga fixes atmospheric nitrogen and releases nitrogenous compounds in leaf cavities. This symbiotic system is the main source of algal biofertilizer in rice fields.

For biogas production besides dung an extensive use of which weed is recommended in our country–

Mangifera indica
Hydrilla
Eicchomia crassipes
Solanum

DIRECTIONS : Each questions contain STATEMENT-1 (Assertion) and STATEMENT-2 (Reason). Each question has 4 choices (a), (b), (c) and (d) out of which ONLY ONE is correct.

Statement 1 : Bioenergy is the energy available from biological sources.

Statement 2 : Fossil fuels are examples of bioenergy.

Statement - 1 is True, Statement - 2 is True, Statement - 2 is a correct explanation for Statement - 1
Statement - 1 is True, Statement - 2 is True ; Statement - 2 is NOT a correct explanation for Statement - 1
Statement - 1 is True, Statement - 2 is False
Both the Statements are False.

Solution

Bioenergy is the energy extracted from biological sources, both living and their immediate remains e.g.wood, gobar gas. It does not include fossil fuels (coal,petroleum, natural gas) etc.

DIRECTIONS : Each questions contain STATEMENT-1 (Assertion) and STATEMENT-2 (Reason). Each question has 4 choices (a), (b), (c) and (d) out of which ONLY ONE is correct.

Statement 1 : Vitamins B₂ is found in cereals, green vegetables, brewer’s yeast, egg white, milk and liver.

Statement 2 : It can be commercially produced by some yeasts.

Statement - 1 is True, Statement - 2 is True, Statement - 2 is a correct explanation for Statement - 1
Statement - 1 is True, Statement - 2 is True ; Statement - 2 is NOT a correct explanation for Statement - 1
Statement - 1 is True, Statement - 2 is False
Both the Statements are False.

Solution

Besides cereals, green vegetables, brewer's yeast, egg white, vitamin B₂ is also produced by intestinal bacteria. The vitamin was first obtained in 1938 using wild strain of mould Ashbhya gossypii. Vitamin B₂ is essential for normal growth and reproduction in a number of laboratory animals.

Methanogens grow anaerobically on cellulosic material and produce

1. methane

2. oxygen

3. carbon dioxide

4. hydrogen

1, 3 and 4
1, 2, 3 and 4
2, 3 and 4
1 and 2

Which of the following bacteria help in nitrogen fixation from atmosphere?

1. Azotobacter
2. Rhizobium
3. Azospirillum
4. Lactobacillus

1, 3 and 4
1, 2, 3 and 4
2, 3 and 4
1, 2 and 3

Microbes are used in

1. primary treatment of sewage

2. secondary treatment of sewage K

3. anaerobic sludge digester

4. production of bioactive molecules

1, 3 and 4
1, 2, 3 and 4
2, 3 and 4
3 and 4

Read the following statement having two blanks (A and B):“A drug used for _____(A)_____ patients is obtained from a species of the organism ______(B)______.” The one correct option for the two blanks is

Solution

Trichoderma is a species of filamentous fungi. Cyclosporin A is immunosuppressive drug obtained from Trichoderma and used in organ transplantation.

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