Tag: evs

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Questions Related to evs

Multiple choice evs a seeds tells a farmer's story manure manures and fertilisers water absorption organ

Which of the following is essential for nitrogen fixation in legumes?

  1. Anthocyanin

  2. Phycocyanin

  3. Phycoerythrin

  4. Leghaemoglobin
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Leguminous plants are in symbiotic association with nitrogen-fixing bacteria like Rhizobium. These bacteria invade root hairs of leguminous plants and forms root nodules in which they fix nitrogen. A red pigment present in the root nodules of leguminous plants is known as leghaemoglobin. Leghaemoglobin is an oxygen-carrier molecule.  It protects nitrogen-fixing enzyme nitrogenase from the side effect of oxygen as the enzyme is highly sensitive to oxygen.

Thus, the correct answer is 'Leghaemoglobin.'

Multiple choice evs a seeds tells a farmer's story manure manures and fertilisers water absorption organ

Which of the following is correct about legumes?

  1. They are incapable of fixing nitrogen

  2. They fix nitrogen with the help of bacteria that live in their leaves

  3. They fix nitrogen with the help of bacteria that live in their roots

  4. They fix nitrogen independent of bacteria
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Legumes are in symbiotic association with nitrogen-fixing bacteria like Rhizobium. They fix nitrogen with the help of bacteria that live in their roots. These bacteria invade root hairs of leguminous plants and forms root nodules in which they fix nitrogen. Rood nodules are found in some other plants also apart from leguminous plants. A red pigment present in the root nodules of leguminous plants is known as leghaemoglobin. 

Thus, the correct answer is 'They fix nitrogen with the help of bacteria that live in their roots.'

Multiple choice evs a seeds tells a farmer's story manure manures and fertilisers water absorption organ

In root nodules of legumes, the role of leghemoglobin is

  1. To transports oxygen to root nodules

  2. To act as an oxygen scavanger

  3. To act as a catalyst in transamination

  4. To provide energy to nitrogen fixing bacteria
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Atmospheric nitrogen is not available to the plants. Nitrogen fixing bacteria converts atmospheric nitrogen into ammonium compounds and make it available to the plants. There are two types of bacteria, free-living and symbiotic. Example of free living nitrogen fixing bacteria include Azotobacter. The example of symbiotic nitrogen fixing bacteria includes Rhizobium. Rhizobium lives in symbiotic association with the legume plants in the root nodules and fixes atmospheric nitrogen. Root nodules of legume plants contains leghaemoglobin. This acts as an oxygen scavanger. 

Thus, the correct answer is 'Acts as an oxygen scavanger.'

Multiple choice evs a seeds tells a farmer's story manure manures and fertilisers water absorption organ

A red pigment present in the root nodules of leguminous plants is known as

  1. Phycoerythrin

  2. Bacteriochlorophyll

  3. Leghaemoglobin

  4. Bacterioviridin
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Leguminous plants are in symbiotic association with nitrogen-fixing bacteria like Rhizobium. These bacteria invade root hairs of leguminous plants and forms root nodules in which they fix nitrogen. A red pigment present in the root nodules of leguminous plants is known as leghaemoglobin. Leghaemoglobin is an oxygen-carrier molecule.  It protects nitrogen-fixing enzyme nitrogenase from the side effect of oxygen as the enzyme is highly sensitive to oxygen.

Thus, the correct answer is 'Leghaemoglobin.'

Multiple choice evs a seeds tells a farmer's story manure manures and fertilisers water absorption organ

Which of the following plants are used as green manure in crop field and in sandy soils?

  1. Crotalaria juncea and Alhagi camelorum

  2. Calotropis procera and Phyllanthus niruri

  3. Saccharum munja and Lantana camara

  4. Dichanthium annulatum and Azolla nilotica
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Crotalaria juncea and Alhagi camelorum are used as green manure in crop fields and sandy soils because these plants, when grown, replenish the soil with sufficient nutrients and nitrogen content after its usage by the crop plant.

So, the correct option is 'Crotalaria juncea and Alhagi camelorum'.

Multiple choice evs a seeds tells a farmer's story manure manures and fertilisers water absorption organ

Leghaemoglobin functions as

  1. Oxygen scavenger

  2. Nitrogen scavenger
  3. $CO _2$ scavenger

  4. Hydrogen carrier
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The root nodules of the leguminous plants contain an oxygen-binding heme protein called leghemoglobin. It is present in the cytoplasm of infected nodule cells at high concentrations. The function of  leghemoglobin is to help transport oxygen to the respiring symbiotic bacterial cells in a manner analogous to hemoglobin transporting oxygen to respiring tissues in animals. It has a high affinity for oxygen (approximately, ten times higher than the ß chain of human hemoglobin). Thus, it acts as a oxygen scavenger.
Hence, the correct answer is option (A).

Multiple choice evs a seeds tells a farmer's story manure manures and fertilisers water absorption organ

Identify the role of lectins in formation of root nodules in legumes.

  1. Formation of shepherd's crook

  2. Recognition of compatible Rhizobium by host

  3. Formation of peribacterial membrane

  4. Formation of infection thread
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Lectins are sugar-binding proteins that play a key role in the recognition and attachment of compatible Rhizobium bacteria to the root hairs of host leguminous plants.

Multiple choice evs a seeds tells a farmer's story manure manures and fertilisers water absorption organ

Function of red pigment leghaemoglobin present in root nodules of leguminous plants is to regulate

  1. $CO _2$ supply in cells

  2. Mo supply to cells
  3. $O _2$ supply to cells

  4. Production of phenolic compounds
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The root nodules of the leguminous plants contain an oxygen-binding heme protein called leghemoglobin. It is present in the cytoplasm of infected nodule cells at high concentrations. This leghemoglobin has a high affinity for oxygen, (approximately, ten times higher than the ß chain of human hemoglobin). Its function is to help transport oxygen to the respiring symbiotic bacterial cells in a manner analogous to hemoglobin transporting oxygen to respiring tissues in animals. Thus, it regulates oxygen supply to the cells.
Thus, the correct answer is option (C). 
Multiple choice evs a seeds tells a farmer's story manure manures and fertilisers water absorption organ

Leghaemoglobin takes part in

  1. Energy release

  2. Stimulating growth of rhizobium
  3. $N _2$ absorption
  4. Protecting nitrogenase from $O _2$

  5. Supply of oxygen
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The root nodules contain pink colored pigment contains a protein called leg-hemoglobin.

Leg-haemoglobin acts as an oxygen scavenger and provides anaerobic conditions to the bacteria.
So the correct answer is 'protecting nitrogenase from oxygen'

Multiple choice evs a seeds tells a farmer's story manure manures and fertilisers water absorption organ

Leghaemoglobin occurs in

  1. Coralloid root

  2. BGA

  3. Around bacterial infections of root nodules

  4. Mycorrhiza
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Leghaemoglobin is an oxygen carrier found in the nitrogen fixing root nodules of leguminous plants. Rhizobium is a free living bacteria that can fix atmospheric nitrogen.

Steps involved in nodule formation are
1.Rhizobium bacteria contact a susceptible root hair.
2.After this they will divide near it.
3.Then Rhizobium infects the root hair causing it to curl.
4.Infected thread carries the bacteria to the inner cortex.
5.The bacteria get modified into rod shaped bacteroids and cause inner cortical and pericycle cells to divide.
6.Division lead to nodule formation.
So the correct answer is 'Around bacterial infections of root nodules'