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 Multiple Choice QuestionsMultiple Choice Questions

1.

Micro-organism which act as a vehicle for foreign gene transfer in higher plants

  • Agrobacterium

  • E. coli

  • T.M.V.

  • Bacillus anihracis


A.

Agrobacterium

The bacterium-Agrobacterium acts as a vehicle for transfer of DNA or genes from one organism to another organism because it infects all dicot plants.


2.

Which one of the following proved effective for biological control of nematodal diseases in plants?

  • Pisolithus tinctorius

  • Pseudomonas cepacin

  • Gliocladium virens

  • Paceilomyces Lilacinus


D.

Paceilomyces Lilacinus

Paexcilomyces Lilacinus is proved effective for biological control of nematodal  disease in plants. it is easily produced in vitro, Rhizosphere competent, attack the eggs of several nematodes species and treatment of plant matter, eg, seed tuber, can be effective.

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3.

The Triticale is an intergeneric hybrid between

  • wheat and maize

  • maize and rye

  • wheat and rye

  • bajra and wheat


C.

wheat and rye

The Triticale is the first man made cereal. It is formed by a cross between wheat (Triticum) and rye (Secale cerale) followed by allopolyploidy (multiplication of non- homologous chromosomes).

Triticum sp × Secale cerale 

Diploid

                      Allopolyploidy

Triticale


4.

One gene- one enzyme hypothesis of Beadle and Tatum was experimentally proved on

  • Saccharomyces 

  • Neurospora crassa

  • Lathyrus odoratus

  • Claviceps


B.

Neurospora crassa

One gene- one enzyme theory was given by Beadle and Tatum in 1958, while they were working on red mould or Neurospora crassa (Ascomycetes fungus), which is also called Drosophila of plant kingdom.


5.

Farmers in a particular region were concerned that pre-mature yellowing of leaves of a pulse crop might cause decrease in the yield. Which treatment could be most beneficial to obtain maximum seed yield?

  • Frequent irrigation of the crop

  • Treatment of the plants with cytokinins alongwith a small dose of nitrogenous fertilizer

  • Removal of all yellow leaves and spraying the remaining green leaves with 2,4,5- trichlorophenoxy acetic acid

  • Application of iron and magnesium to promote synthesis of chlorophyll


D.

Application of iron and magnesium to promote synthesis of chlorophyll

If a pulse crop possesses premature yellowing of leaves and decrease in yield and application of magnesium and iron to promote synthesis of chlorophyll may become most beneficial to overcome the problem and to obtain maximum seed yield.
Magnesium is an important part of ring structure of chlorophyll molecule and its deficiency causes chlorosis and premature leaf abscission.
In iron deficiency also, the leaves become chlorotic because iron is required for the synthesis of some of the chlorophyll protein complexes in the chloroplast.

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6.

Which of the following pairs is correctly matched

  • Central dogma- Codon

  • Okazaki fragments - Splicing

  • RNA polymerase -RNA primer

  • Restriction enzymes - Genetic engineering


D.

Restriction enzymes - Genetic engineering

Restriction enzyme recognises specific nucleotide sequences in DNA and then makes a double-stranded cleavage of DNA molecule. Restriction enzymes are called genetic scissors as they slice off genes and is recently being used in gene therapy technique. They are key tool of genetic engineering. Central dogma is related with protein synthesis. Okazaki fragments are found during DNA synthesis and RNA polymerase is used in synthesis of RNA.


7.

Bacillus thuringiensis (Bt) strains have been used for designing novel

  • bio- metallurgical technique

  • bio- mineralization processes

  • bio- insecticidal plants

  • biofertilizers


C.

bio- insecticidal plants

Bioinsecticides are those biological agents, which are used to control harmful insects. A bacterium, Bacillus thuringiensis is used for this purpose. Spores of this bacterium produce the insecticidal cry-protein. Therefore, spores, of this bacterium kill larvae of certain insects. The commercial preparations of B. thuringiensis contain a mixture of spores, cry-protein and an inert carrier.


8.

Genes for cytoplasmic male sterility in plants are generally located in

  • mitochondrial genome

  • cytosol

  • chloroplast genome

  • nuclear genome


A.

mitochondrial genome

Mitochondria are the eukaryotic cell organelles. These originate from pre-existing mitochondria only. Also known as semi autonomous organelles because they consists of  a circular, double stranded DNA molecule, RNA and 70 S type of ribosome. The genes, located outside of nucleus (i.e., within the cytoplasm) also governes some traits and are referred as plasmogenes or cytoplasmic genes. Cytoplasmic male sterility (i.e., dominance of female cytoplasmic genes over male) is due to plasmogenes located in mitochondrial DNA (mtDNA).


9.

Microbes found to be very useful in genetic engineering are

  • Escherichia coli and Agrobacterium tumefaciens

  • Vibrio cholerae and a tailed bacteriophage

  • Diplococcus sp. and Pseudomonas sp

  • Crown gall bacterium and Caenorhabditis elegans


A.

Escherichia coli and Agrobacterium tumefaciens

Escherichia coli and Agrobacterium tumefaciens are the microbes found to be very useful in genetic engineering. 
E. coli is a motile, gram negative, rod shaped bacterium which is a normal inhabitant of human colon. It is most extensively used in bacterial genetics and molecular biology.
Agrobacterium tumefaciens is a soil bacterium. It has Ti plasmid (Tumour inducing plasmid) and it can be used for the transfer of a desired gene in dicot plants.

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10.

Restriction enzymes are used in genetic engineering, because they

  • can degrade harmful proteins

  • can join different DNA fragments

  • can cut DNA at specific base sequence

  • are nucleases that cut DNA at variable sites


C.

can cut DNA at specific base sequence

Restriction enzyme are also known as molecular knifes or molecular scissors. They are isolated from bacteria. They recognize specific base sequence in DNA and cleave both strands of it.