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

Which of the following statements are FALSE regarding fungi?

  1. Food materials are stored in the form of starch.
  2. The cell wall is made up of chitin.
  3. Fungi are always autotrophs.
  4. Thallus is made up of pseudo parenchyma.

  1. Only 1 and 2

  2. Only 1and 3

  3. Only 1and 4

  4. Only 2 and 3

  5. Only 3 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Yes, it is correct, as both are false. In fungi, food materials are stored in the form of glycogen, and fungi are heterotrophs due to absence of chlorophyll.

Multiple choice

Which of the following plant diseases are caused by fungus? P. Ergot of Rye Q. Powdery mildew of cucurbits R. Crown gall of hemp S. Black rot of crucifers

  1. Only P and Q

  2. Only P and R

  3. Only P and S

  4. Only Q and R

  5. Only R and S
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yes, both are caused by fungus. Ergot of Rye is a plant disease that is caused by the fungus Claviceps purpurea. Powdery mildew of cucurbits is caused by two fungus: Sphaerotheca fuliginea and Erysiphe cichoracearum.

Multiple choice

Which of the following fungi is best known as an insect parasite?

  1. Rhizopus oryzae

  2. Saksenaea vasiformis

  3. Aspergillus fumigatus

  4. Beauveria bassiana

  5. Fusarium
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This fungi is usually as a saprophytic contaminant. World-wide, known as an insect parasite. Sympodial development of single-celled conidia on a narrow geniculate or zig-zag rachis emanating from a flask-shaped conidiophore.

Multiple choice

After complete medical check up, doctor told a couple that their daughter is suffering from CNS zygomycosis, which is a fungal disesae. Which of the following is the causative agent of CNS zygomycosis?

  1. Absidia corymbifera

  2. Conidiobolus coronatus

  3. Cunninghamella bertholletiae

  4. Mucor

  5. Rhizomucor pusillus
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

It is a common human pathogen causing pulmonary, rhinocerebral, disseminated, CNS  zygomycosis. It is a small pyriform shaped sporangia with a characteristic conical shaped columellae and pronounced apophysis.

Multiple choice

Keratin is the key structural material making up the outer layer of human skin. Which of the following diseases is caused by a fungus, which have the ability to utilise keratin as a nutrient source?

  1. Candidiasis

  2. Chronic Candida onychomycosis

  3. Pityriasis folliculitis

  4. Paronychia

  5. Dermatophytosis
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Dermatophytosis of the scalp, glabrous skin, and nails is caused by dermatophytes which have the ability to utilise keratin as a nutrient source. No living tissue is invaded, the keratinised stratum corneum is simply colonised.

Multiple choice

In a hospital, after a thoorugh check up, it was confirmed that Jacob's 12 year old sister is suffering from a fungal disease which is characterised by draining sinuses, granules and tumefaction. Which of the following diseases is she be suffering from?

  1. Pityriasis

  2. Cutaneous Mycoses

  3. Sporotrichosis

  4. Chromoblastomycosis

  5. Mycetoma
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

It is a mycotic infection of humans and animals caused by a number of different fungi, and actinomycetes characterised by draining sinuses, granules and tumefaction. The disease results from the traumatic implantation of the aetiologic agent, and usually involves the cutaneous and subcutaneous tissue.

Multiple choice

Which of the following is a causative agent of swamp cancer especially in horses?

  1. Shizophyllum

  2. Pythium insidiosum

  3. Apophysomyces elegans

  4. Basidiobolus ranarum

  5. Conidiobolus coronatus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Pythium insidiosum is the causative agent of swamp cancer especially in horses, mainly in wet tropical environments. Infections are characterised by tumour-like masses, which develop mostly on the legs.

Multiple choice

Mycotic abortion is common only in cattles. Which of the following is the causative agent of bovine mycotic abortion?

  1. Cunninghamella bertholletiae

  2. Mortierella wolfii

  3. Lichtheimia corymbifera

  4. Saksenaea vasiformis

  5. Syncephalastrum racemosum
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Mortierella wolfii is an important casual agent of bovine mycotic abortion, pneumonia and systemic mycosis. It has also been isolated from soil, rotten silage, hay and coal spoil tips.

Multiple choice

The blood samples of an old man showed levels of aflatoxins, which is a potent liver carcinogen. Which of the following fungi is associated with the production of aflatoxins?

  1. Aspergillus versicolor

  2. Aspergillus ustus

  3. Aspergillus parasiticus

  4. Aspergillus oryzae

  5. Aspergillus sojae
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Aspergillus parasiticus is a mold known to produce aflatoxins,  which is a potent liver carcinogen. It is closely related Aspergillus flavus.