Tag: zoology

Questions Related to zoology

Bt toxin protein crystals present in bacterium Bacillus thuringiensis, do not kill the bacteria themselves because

zoology sustainable agriculture microbes and farming biopesticide environmental protection

  1. Bacteria are resistant to the toxin

  2. Toxins occor as inactive protoxins in bacteria

  3. Bacteria enclose toxins in a special sac

  4. None of these

Show answer
Correct Option: B
Explanation:

Soil bacterium Bacillus thruingiensis (Bt) produces proteins that kill certain insects like lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes).Bacillus thuringinesis forms some intracellular protein crystals. These crystals contain a toxic insecticidal protein. The Bt toxin protein exists as an inactive toxin and is converted into an active form due to the alkaline pH of the alimentary canal that solubilities the crystals. The activated toxin binds to the surface of midgut epithelial cells and creates pores which cause cell swelling and lysis and finally cause the death of the insect.

So, the correct answer is 'Toxins occur as inactive protoxins in bacteria'.

The free-living fungus Trichoderma can be used for:

zoology sustainable agriculture microbes and farming biopesticide environmental protection

  1. killing insects

  2. biological control of plant diseases

  3. controlling butterfly caterpillars

  4. producing antibiotics

Show answer
Correct Option: B
Explanation:

Trichoderma species are free living fungi that are very common in the root ecosystems. They are effective biocontrol agents of several plant pathogens like Fusarium, Phytopthora etc and used in the treatment of plant diseases.

So, the correct answer is 'biological control of plant diseases' 

What causes the inactive form of Bt toxin i.e. protoxin to get converted into its active form in the body of an insect?

zoology sustainable agriculture microbes and farming biopesticide environmental protection

  1. Temperature of the gut

  2. Enzymes present in the saliva

  3. Alkaline pH of the gut

  4. There is no specific reason

Show answer
Correct Option: C
Explanation:

Soil bacterium Bacillus thruingiensis (Bt) produces proteins that kill certain insects like lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes).Bacillus thuringinesis forms some intracellular protein crystals. These crystals contain a toxic insecticidal protein. The Bt toxin protein exists as an inactive toxin and is coverted into an active form due to the alkaline pH of the alimentary canal that solubilities the crystals. The activated toxin binds to the surface of midgut epithelial cells and creates pores which cause cell swelling and lysis and finally cause death of the insect.

So, the correct answer is 'Alkaline pH of the gut'.

Which of the following is not used as a biopesticide?

zoology sustainable agriculture microbes and farming biopesticide environmental protection

  1. Trichoderma harzianum

  2. Nucleopolyhedrovirus

  3. Xanthomonas campestris

  4.  Bacillus thuringiensis

Show answer
Correct Option: C
Explanation:

Xanthomonas campestris is not used as a biopesticide. Bacillus thuringiensis is used as a microbial biocontrol agent. Trichoderma harzianum is a free-living fungi, common in soil and root ecosystems. It is an effective biocontrol agent of several plant pathogens. Viruses of the family Baculoviruses are pathogens that attack insects and other arthropods. The majority of baculoviruses used as biological control agents belong to genus Nucleopolyhedrovirus. So, the correct answer is 'Xanthomonas campestris'.

Biopesticides are:

zoology sustainable agriculture microbes and farming biopesticide environmental protection

  1. The chemicals which are used to destroy the pests

  2. The living organisms or their products which are used for the pest control

  3. The organisms which destroy the crops

  4. None of these.

Show answer
Correct Option: B
Explanation:

Biopesticides are those biological agents or their products that are used for the control of weeds and insects (pathogens). A most important example is the soil bacterium, Bacillus thuringiensis.

Given below is the list of few chemicals that are used for protection of crops
i) dalapon 

ii) butachlor 
iii) malathion 
iv) simazine 
v) disyston 
vi) gammexane
How many of these are used as insecticides?

zoology sustainable agriculture microbes and farming biopesticide environmental protection

  1. 3

  2. 4

  3. 2

  4. 5

Show answer
Correct Option: A
Explanation:
 Name of the compound  uses
 Dalapon It is used as a herbicide and acts on the perennial grasses. It controls the specific weed species and leaving the desired crops relatively unharmed.
 Butachlor It is used as a herbicide. It is mainly used in the form of granules in rice.
 Malathion It is used as an insecticide. It is basically used in mosquitoes eradication. 
 Simazine It is used as a herbicide. It is used to control broad-leaved weeds and annual grasses.
 Disulfoton It is used as an insecticide. It is effective against the sucking insects e.g. beet flies, 
 Gammexane It is used both as an agricultural insecticide and pharmaceutical purpose.

So, the correct answer is ' 3'.

A biological control which is effective biocontrol agent for several plant pathogens : 

zoology sustainable agriculture microbes and farming biopesticide environmental protection

  1. Nucleopolyhedrovirus

  2. Tirchoderma

  3. Agrobacterium

  4. Bacillus

Show answer
Correct Option: A
Explanation:

Trichoderma are fungi and present in the soil as avirulent symbionts.

Agrobacterium has a unique ability to transfer its DNA to the plants and hence it is manipulated by genetic engineering to make the crop pathogen resistance.
But the biocontrol agent for several plant pathogens is Nucleopolyhedrovirus. It is a virus that infects the pests like butterfly, moth, etc.
So the correct answer is ' Nucleopolyhedrovirus'. 

Which of the following pairs is wrongly matched?

zoology sustainable agriculture microbes and farming biopesticide environmental protection

  1. Activated : Secondary treatment

  2. Gobar gas : ${ CH } _{ 4 }+{ CO } _{ 2 }$

  3. Biopesticide : Xanthomonas campestris

  4. Detergent formulations : Lipases

Show answer
Correct Option: C
Explanation:

Xanthomonas campestris is an aerobic, gram-negative rod known to cause the black in crucifers by darkening the vascular tissues. Host-associated, over 20 different pathovars of V.Campestris have been identified by their distinctive pathogenicity on a wide range of plants including crops and wild plants.

So, the correct option is 'Biopesticide: Xanthomous campestris'.

Refer to the given dichotomous key and select the correct option.
I.   (a) Fibre obtained from natural sources - Go to II
     (b) Fibre obtained from chemical, - K
II.  (a) It is a cellulosic fibre - Go to III
     (b) It is a protein fibre. - Go to IV
III. (a) It is obtained from leaves. - L
     (b) It is obtained from seeds.
IV. (a) It is obtained from mammals. - N
     (b) It is obtained from an insect. - O

zoology sustainable agriculture microbes and farming biopesticide environmental protection

  1. Fabrics fibres K and N could be water proof.

  2. When fibres L and M are burnt separately they give smell of burning paper and burning hair, respectively.

  3. Fibre L is separated from leaves by retting process whereas from seeds by ginning process.

  4. N can be obtained from the same animal repeatedly whereas O can be obtained from source animal only once in its lifetime.

Show answer
Correct Option: A
Explanation:

Fabrics fibers K and N are usually laminated to or coated with a waterproofing material such as rubber, polyvinyl chloride (PVC), polyurethane (PU), silicone elastomer, fluoropolymers, and wax

So, the correct option is 'Fabrics fibers K and N could be waterproof'.

Which is useful as biological control ?

zoology sustainable agriculture microbes and farming biopesticide environmental protection

  1. Mucor mucedo

  2. Trichoderma viridae

  3. Penicillium notatum

  4. Phytophthora parasitica

Show answer
Correct Option: B