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 biology breeding and biotechnology method of plant breeding for crop improvement plant breeding for food production biotechnology

The Ear cockier of wheat can be differentiated from Molya disease of wheat by the fact that in the former.

  1. Plants become dwarf, stem and leaves become twisted spike lets get distorted and grains get replaced by brown stony structures

  2. Plants become pale, leaves turn yellow with reddish lip, roots get matted and fail to ear

  3. Root tips swell and cyst adheres to roots that turn brown and fall

  4. Show hypertrophy of stern and leaves and roots swell
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ear cockle of wheat is caused by the nematode Anguina tritici, which causes the formation of galls (brown stony structures) in place of grains and distorts the spikelets.

Multiple choice biology breeding and biotechnology method of plant breeding for crop improvement plant breeding for food production biotechnology

Which pathogen causes the blast disease of rice?

  1. Cercospora personata

  2. Pyricularia oryzae

  3. Xanthomonas citri

  4. Tungro virus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Blast disease in rice is caused by the fungus Magnaporthe oryzae which was earlier known as Pyricularia oryzae. Different parts of the plants are affected by the fungus. The blast can occur wherever blast spores are present. Rice can have blast in all growth stages. There are lesions formed on the leaf, panicle and neck region of the plant. There is great loss in yield due to this disease affecting the rice plants.
Thus, the correct answer is option B.
Multiple choice botany ecosystem energy flow in food chain food chain and energy flow energy flow in ecosystem

Which bacteria consumes organic matter as their food, and thus oxidizing it to stable end product?

  1. Viruses

  2. Aerobic Bacteria

  3. Anaerobic Bacteria

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

Aerobic bacteria require oxygen to break down organic matter into stable end products like carbon dioxide and water. Anaerobic bacteria function in the absence of oxygen, and viruses are not organisms that consume organic matter in this way.

Multiple choice evs farming brings prosperity agriculture and types of crops crop management management of crops in india

Which one of the following pathogens infect unfertilized ovary in wheat?

  1. Puccinia graminis tritici

  2. Puccinia recondita

  3. Usilago nuda tritici

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

Ustilago nuda tritici causes loose smut of wheat, a fungal disease that infects the unfertilized or developing ovary within the flower. The fungus replaces the grain with masses of dark spores.

Multiple choice botany know the plant world closely nutrition and its types types of nutrition in plants different modes of nutrition in plants

A partial parasite is?

  1. Cuscuta

  2. Cassytha

  3. Arceuthobium

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

Viscum is a partial stem parasite among the following because it depends on its host for only water and minerals. It can prepare its own food through photosynthesis as it is chlorophyllous.

So the correct option is 'Viscum'.

Multiple choice botany know the plant world closely nutrition and its types types of nutrition in plants different modes of nutrition in plants

Saprophytes are likely to grow on 

  1. Bread pieces

  2. Pickles when kept in moist places

  3. On the ground after rains

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

Saprophytes are organisms that can't make their own food. In order to survive, they feed on dead and decaying matter. Fungi and a few species of bacteria are saprophytes. They grow tubular structures, or hyphae, which are filaments that grow and branch into the dead matter, produce digestive enzymes and digest away the dead organism. In order for a saprotrophic organism to facilitate optimal growth and repair, favourable conditions and nutrients must be present.[4] Optimal conditions refer to several conditions which optimize the growth of saprotrophic organisms, such as;

  • Presence of water: 80–90% of the fungi is composed of water by mass, and requires excess water for absorption due to the evaporation of internally retent water.
  • In terms of nitrogen-rich sources, saprotrophs require combined protein for the creation of proteins, which is facilitated by the absorption of amino acids, and usually taken from the rich soil.
  •  Fungi, bread mould, some protists, and many bacteria are saprophytic in nutrition.

So, the correct answer is 'All of the above'.

Multiple choice biology biodiversity and classification monera five kingdoms of living organisms biodiversity and need of classification

Ray fungi are

  1. Phycomycetes

  2. Ascomycetes

  3. Actinomycetes

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

Ray fungi are also called as Actinomycetes. They form a mycelium consisting of narrow hyphae. They show characteristics of both fungi and bacteria. They form the normal part of the mouth flora in the human. They produce many antibiotics like streptomycin, actinomycin and chloromycin. 

Thus, the correct answer is 'Actinomycetes.'

Multiple choice botany bacteria bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Torula condition' occurs in ________.

  1. Rhizopus

  2. Ulothrix

  3. Spirogyra

  4. Riccia
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
When some species of like mucor they grow in high concentrated liquid medium of sugar and they brown up into small pieces called odia and further they grow like yeast by budding and this condition called Torula condition.
Hence the correct answer is A. 
Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Sex factor of bacteria is

  1. RNA

  2. Sex pili

  3. F-factor

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

F-factor is also called as fertility factor. It is the sex factor of bacteria. It allows the transfers of genes from one bacterium carrying the factor to another bacterium lacking the factor by the process of conjugation. It is found in some bacteria only.

Thus, the correct answer is 'F-factor.'

Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Murein of bacterial cell wall is derivative of

  1. Vitamin

  2. Fat

  3. Organic acid

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

The bacterial cell wall is made up of Peptidoglycan or murein. It is a polymer that is made up of sugars and amino acids. The sugar component is made up of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). NAM is then attached to an amino acid chain of L-alanine, D-glutamic acid, diaminopimelic acid (DAP) and D-alanine. 

Thus, the correct answer is 'Sugar.'

Multiple choice evs - i community health and hygiene drug, tobacco and alcohol consumption addiction and dependence important stages in agricultural development disorders of nervous system

Cyclosporin A, an immunosuppressive drug is produced by

  1. Aspergillus niger

  2. Monascus purpureus

  3. Penicillium notatum

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

Cyclosporin is used as immuno depressant, this drug is derived from a fungus Trichoderma polysporum and inhibit the activity of helper - T cells, thus help to prevent rejection of organ transplant.

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

Organisms called methanogens are most abundant in a

  1. Hot spring

  2. Sulphur rock

  3. Cattle yard

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

Methanogens are the primitive bacteria belonging to archaea which are able to produce methane through the process of methanogenesis. 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 cattle. The methane is released along with the other wastes by the cattle and so, methane is found abundantly in the cattle yard. 

Thus, the correct answer is option C.