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 bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

Xanthomonas citri is related to

  1. Disease in Xanthium

  2. Xanthophyceae

  3. A virus

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

Citrus canker is a disease that is caused by the bacterium Xanthomonas axonopodis. It affects the Citrus species of fruits such as lime, oranges, grapefruit. It results in the lesions on the leaves, stems, fruit and other parts of the citrus plants.

Thus, the correct answer is 'Citrus canker.' 

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

Which one causes blight disease of rice?

  1. Xanthomonas oryzae

  2. Pseudomonas oryzae

  3. Erwinia oryzae

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

Blight disease of Rice is a deadly disease that affects the cultivated rice. It is caused by bacteria Xanthomonas oryzae. It causes wilting of seedlings and yellowing and drying of leaves.

Thus, the correct answer is 'Xanthomonas oryzae.'

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

Little leaf disease and plant yellows are caused by

  1. Halobacterium

  2. Mycoplasma

  3. Bdellovibrios

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

Little leaf disease is a disease that affects brinjal. Symptoms include reduction in leaf size and rosette like appearance. It is transmitted by leafhopper. It is caused by Mycoplasma. Apart from this, Mycoplasma also causes witches' broom disease and plant yellows diseases.

Thus, the correct answer is 'Mycoplasma.'

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

Citrus canker is caused by

  1. Bacteria

  2. Virus

  3. Fungus

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

Citrus canker is a disease that is caused by the bacterium Xanthomonas axonopodis. It affects the Citrus species of fruits such as lime, oranges, grapefruit. It results in the lesions on the leaves, stems, fruit and other parts of the citrus plants.

Thus, the correct answer is 'Bacteria.' 

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

Which among the following is a bacterial disease?

  1. Rust of Tea

  2. Red rot of Sugarcane

  3. Citrus canker

  4. Late blight of Potato
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Rust of Tea is also called as red rust disease. It is caused by algae Cephaleuros parasiticus Karst. It affects the tea plant. Red rot is a disease that affects the sugarcane plant. It is caused by fungus Glomerella tucumanensis. Citrus canker is a bacterial disease affecting Citrus species caused by the Xanthomonas axonopodis. It affects Citrus species like lime, orange. Late blight is an infection caused by fungus Phytophthora infestans. It affects potato and tomato.

Thus, the correct answer is 'Citrus canker.'

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

A plant disease which is not caused by a fungus is

  1. Red rot of Sugarcane

  2. Late blight of Potato

  3. Black rot of crucifers

  4. Brown rust of wheat
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Red rot disease is caused by the fungus Glomerella tucumanensis. It produces a structure called as acervuli. This results in profuse sporulation. Late blight of Potato is caused by fungus Phytophthora infestans. It infects and destroys the leaves, stems, fruits, tubers of potato and tomato plants. Black rot of crucifers is caused by bacterium Xanthomonas campestris. It results in dark brown discoloration of the leaves of fruit and vegetables. Wheat leaf rust is a disease caused by fungus Puccinia triticina. It affects wheat, barley and rye stems, leaves and grains. 

Thus, the correct answer is 'Black rot of crucifers.'

Multiple choice botany biodiversity and classification common diseases in humans epidemics transmission of diseases

Choose the correct answers from the alternatives given.
In defining fungi, which of the following is not a correct contrasting statement?

  1. Animals are heterotrophic by ingestion while fungi are heterotrophic by absorption

  2. Plants have cell walls of cellulose; fungi have cell walls of chitin

  3. Energy reserve of fungi.is starch while the energy reserve of animals is glycogen

  4. Fungi lack flagella at all stages of their life while most protists have a stage that possesses flagella
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Reserve food material in all the fungi is glycogen and oil but not starch. 

So, the correct option is 'Energy reserve of fungi.is starch while the energy reserve of animals is glycogen'.

Multiple choice botany biodiversity and classification common diseases in humans epidemics transmission of diseases

The fungi are

  1. Autotrophic

  2. Holotrophic

  3. Chemotrophic

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

Fungi are multicellular, eukaryotic, heterotrophs, that acquire their nutrients by absorption. Heterotrophic nutrition is a type of nutrition which is obtained by digested organic compounds. They feed on dead or decaying organic matter.

Therefore, the correct answer is option D.

Multiple choice business organisation and correspondence environmental pollution and industries air pollution and its effects the environment and us environment and conservation

Anthracosis is caused by

  1. Iron dust

  2. Coal dust

  3. Cane fibre

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

Anthracosis is the clinical disorders of the respiratory tract that is caused due to deposition of the coal dust due to inhalation of polluted air. It is a form of pneumoconiosis. Due to this, the lungs are rendered black in colour. It is also called the Miner's disease as the coal mine workers are worst affected by it. It affects the bronchi and alveoli surface area. This illness can be seen in smokers as well. Pulmonary emphysema and chronic bronchitis are the severe effects of anthracosis. 

Hence, the correct answer is 'Coal dust'.

Multiple choice biology micro organisms non cellular organism : virus world of virus bacteria - introduction, shape and structure

Which of the following can be made into crystal form?

  1. Algae

  2. Amoeba

  3. Virus

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

Viruses can be made into a crystalline form. TMV became the first virus to be crystallized in 1935. One crystal of viruses consists of thousands of viruses. The crystallization of viruses was first done by Stanley. Algae, Amoeba and Sperm cannot be crystallised.

The correct answer is C.

Multiple choice biology micro organisms non cellular organism : virus world of virus bacteria - introduction, shape and structure

The organisms which display properties of both living and nonliving are

  1. Viruses

  2. Diatoms

  3. Lichens

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

Virus is the microorganisms which have properties of living and non-living both. They have a specific structure which consists of head and tail. Head is composed of several protein units known as capsomeres which enclose the genetic material made up of RNA or DNA. They have a lipid envelope derived from the host cell membrane which lies outside the capsomere. They occur in crystalline form outside the body of the host but as it enters the host cell it injects its genetic material which replicates vigorously. The replicated materials are further packed in the new protein coat formed using host protein and is thrown out by the lysis of cell membrane.

Multiple choice biology micro organisms non cellular organism : virus world of virus bacteria - introduction, shape and structure

Viruses are non-cellular organisms but replicate themselves once they infect the host cell. To which of the following kingdom do viruses belong to?

  1. Monera

  2. Protista

  3. Fungi

  4. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Viruses are non-cellular organisms and replicate only when they infect the host cell. 

Viruses belong to none of these. Option D.