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

The leaf blight on carrot is caused by

  1. Alternaria triticina

  2. Alternaria solani

  3. Alternaria panax

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

Alternaria carotiincultae is a plant pathogen & causes leaf blight on carrot.

Multiple choice

The bacteria present as a commensal on human skin is

  1. Solobacterium moorei

  2. Staphylococcus aureus

  3. Staphylococcus capitis

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

It is found as a commensal on human skin, but has also been involved in infections of the bloodstream, urinary tract, bones and joints.

Multiple choice

The fungus with bioluminescent characteristic is

  1. Claviceps purpurea

  2. Omphalotus olearius

  3. Cordyceps sinensis

  4. Trametes versicolor
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This fungus is distinguished by its bioluminescent characteristic. Ingestion of even small amounts of this highly toxic fungus can lead to severe diarrhea, vomiting and cramps.

Multiple choice

Which of the following is not a correct match?

  1. Root knot disease – Nematode Heterodera marioni

  2. Smut of bajra – Helminthosporium sacchari

  3. Covered smut of barley – Ustilago nuda

  4. Late blight of potato – Phytophthora infestans
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Covered smut of barley is caused by Ustilago hordei.

Multiple choice

'Watermelon snow' is caused due to

  1. Trichodesmium

  2. Gonyulaux

  3. Chlamydomonas nivalis

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

It causes 'Red snow'. Its hypnospores consist of a red colour pigment, which gives the colour to snow.

Multiple choice

Which process results in dropping of plant leaves, stem and flowers due to water loss?

  1. Leaf spot

  2. Crown gall

  3. Wilting

  4. Fasciation

  5. Downey mildew
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Usually when a plant wilts, it is an indicative of lack of water or moisture . It also occurs due to the presence of some kind of toxin such as introduced by disease or poison. If the soil around the roots of a plant lacks water or the rate of loss of water is faster than the rate of absorption of water, the cells in the plant will contain less water and fail to support the plant. Therefore, it results in dropping of plant parts.

Multiple choice

A division of the circular single stranded viruses has been proposed for easy and convenient study. Which among the following types of genomes is characterised by small circular DNA genome?

  1. Type I genomes

  2. Type II genomes

  3. Type III genomes

  4. Type IV genomes

  5. Type V genomes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Type I genomes are characterized by a small circular DNA genome (approximately 2-kb), with the Rep protein and the major open reading frame (ORF) in opposite orientations. This type is characteristic of the circoviruses, geminiviruses and nanoviruses.

Multiple choice

Which one of the following organisms is a fungus?

  1. Staphylococcus

  2. Salmonella

  3. Clostridium

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

Aspergillus is a genus of fungi, while the other three options are all bacteria. Staphylococcus and Clostridium are genera of bacteria, and Salmonella is a bacterial genus as well.

Multiple choice

Microorganisms cannot survive under

  1. ice cold condition

  2. hot springs

  3. deserts

  4. marshy lands

  5. none of these
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

As they can survive under all types of environment, ranging from ice cold climate to hot springs and deserts to marshy lands, so all are correct. Hence, this is the correct answer.