Biology

Microbes and Plant Diseases

1,118 Questions

Microbes and plant diseases examine the role of fungi, bacteria, and viruses in causing infections in plants and humans. Topics cover symbiotic associations like mycorrhiza, fungal structures, and specific agricultural pathogens. Practice these biology questions to master microbiology concepts for upcoming competitive examinations.

Fungal associationsPlant pathogensMicrobial structuresBacterial infections

Microbes and Plant Diseases Questions

Multiple choice botany the living world archaebacteria the three domains of life classification of microbes

A peculiar odour found in marshy areas and cow sheds is of gas produced by

  1. Archaebacteria

  2. Cyanobacteria

  3. Slime Moulds

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

Methanogen belongs to Archaebacteria group. They are capable of producing methane gas or marshy gas or biogas. They produces methane gas in marshy areas and cow sheds. This produces a peculiar odour.

Thus, the correct answer is 'Archaebacteria.'

Multiple choice botany the living world archaebacteria the three domains of life classification of microbes

Methanogens can be found 

  1. In swamps

  2. In a cow's stomach

  3. In marshes

  4. All of the above

  5. None of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Methanogens are the primitive bacteria belonging to archaea which are able to produce methane. These organisms can utilise the carbon dioxide and hydrogen gas to form methane. These organisms are found in marshy areas where they produce the marsh gas, in swamps and in the stomach of certain animals. These organisms are responsible for methane production in the stomach of cattle which causes belching.

Thus, the correct answer is option D. 

Multiple choice zoology soil pollution industrial chemicals and their harmful effects toxic wastes and their effects soil pollution-causes

Name one frequently used fungicide from the following.

  1. Griseofulvin

  2. Chloramphenicol

  3. Cycocel

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

Griseofulvin is an orally administered antifungal drug. It is used both in animals and humans, to treat fungal infections of the skin (commonly known as ringworm) and nails. It is produced by culture of some strains of the mold Penicillium griseofulvum, from which it was isolated in 1939.

Multiple choice biology useful and harmful microbes mycorrhiza classification of fungi harmful microorganisms

Sclerotia extract of .................. fungus produce a powerful hallucinogenic drug LSD and drug ergotine.

  1. Claviceps purpurea

  2. Aspergillus flavus

  3. Agaricus

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Claviceps purpurea is an ergot fungus that grows on the ears of rye and related cereal and forae plants. Consumption of grains or seeds contaminated with the survival structure of this fungus, the ergot sclerotium, can cause ergotism in humans and other mammals. Ergotine is a powerful astringent alkaloid extracted from ergot as a brown, amorphous, bitter substance. It produces hallucinating effect on humans. Thus, the correct answer is option A.

Multiple choice biology kingdom monera, protista and fungi mycorrhiza classification of fungi useful and harmful microbes

'Ergot' is obtained from

  1. Puccinia

  2. Rhizopus

  3. Claviceps

  4. Yeast
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Ergot are the alkaloids obtained from ergot fungi Claviceps purpurea which grow on rye plant. These fungi cause ergot of rye, a fungal disease in plants. The sclerotia of ergot fungi contain alkaloids which are used to produce LSD (Lysergic acid diethylamide) drugs that act on CNS (Central nervous system). They are natural hallucinogens and change mood, behaviour and thoughts like in psychosis, a condition in which thoughts and emotions are affected to such an extent that contact is lost with reality. 
So, the correct answer is 'Claviceps'.
Multiple choice biology kingdom monera, protista and fungi mycorrhiza classification of fungi useful and harmful microbes

Mucor belongs to .......... sub-division of Eumycota.

  1. Mastigomycotina

  2. Ascomycotina

  3. Zygomycotina

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

Zygomycotina is composed of organisms that are characterized by the formation of ribbon-like aseptate hyphae and sexual reproduction with the formation of zygospores. The vast majority of human zygomycotic disease is caused by the members of the family Mucoraceae. This family includes zygomycetes that produce asexual sporangiospores in sporangia. Sporangium producers which may or may not produce stolons and rhizoids and included in the genera Mucor and Rhizomucor. Thus, the correct answer is option 'Zygomycotina'.  

Multiple choice biology kingdom monera, protista and fungi mycorrhiza classification of fungi useful and harmful microbes

Ergot (of Rye) is obtained from

  1. Claviceps purpurea

  2. Puccinia graminis

  3. Alternaria solanii

  4. Fusarium oxysporum
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ergot of Rye is a plant disease that is caused by the fungus Claviceps purpurea. The so-called ergot that replaces the grain of the rye is a dark, purplish sclerotium.

Therefore A is correct option. 

Multiple choice biology kingdom monera, protista and fungi mycorrhiza classification of fungi useful and harmful microbes

Claviceps purpurea is casual organism of 

  1. Smut of Barley

  2. Rust of Wheat

  3. Ergot of Rye

  4. Powdery Mildew of Pea
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Claviceps purpurea is the fungal pathogen causing ergot disease of rye. It infects rye grains, producing sclerotia containing toxic alkaloids. Smut (Ustilago), rust (Puccinia), and powdery mildew (various fungi) are different plant diseases.

Multiple choice botany bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

Crown Gall is due to

  1. Agrobacterium

  2. Mycobacterium

  3. Clostridium

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

Crown gall disease is a plant disease that is caused by the bacterium Agrobacterium tumefaciens. It results in the overgrowth appearing as knobbly swellings or galls on stems, roots, trunks, and branches. It affects mostly woody shrubs and herbaceous plants like grapes, raspberries, blackberries, and roses.

Thus, the correct answer is 'Agrobacterium.'

Multiple choice botany bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

Agrobacterium tumefaciens causes

  1. Wilt

  2. Damping off

  3. Rust

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

Crown gall disease is a plant disease that is caused by the bacterium Agrobacterium tumefaciens. It results in the overgrowth appearing as knobbly swellings or galls on stems, roots, trunks, and branches. It affects mostly woody shrubs and herbaceous plants like grapes, raspberries, blackberries, and roses.

Thus, the correct answer is 'Crown gall.'