Which is social foresting species
Leucaena leucocephala
Tectona grandis
Mangifera indica
Rosa indica
A.
Leucaena leucocephala
Leucaena leucocephala is commonly known as subabool. It is a very fast growing leguminous plant and therefore is commonly used as social foresting species.
Double fertilization means
fusion of nucleus of male gamete with the egg nucleus
fusion of two polar nuclei
fusion of sperm nucleus with secondary nucleus
fusion of one sperm nucleus with nucleus and fusion of other sperm nucleus with secondary nucleus
D.
fusion of one sperm nucleus with nucleus and fusion of other sperm nucleus with secondary nucleus
Double fertilization was first observed by Nawaschin (1892) in Lilium and Fritillaria and confirmed by Grignard. It is characteristic of angiosperms. In double fertilization first fertilization is normal and second, as it involves three nuclei is known as triple fusion.
Which of the following statement is correct about DDT
It is a biomagnifying biodegradable pollutant
It is non biomagnifying biodegradable pollutant
It is biomagnifying non biodegradable pollutant
It is not a pollutant
C.
It is biomagnifying non biodegradable pollutant
DDT has been recently banned because it is non-biodegradable and biomagnifying pollutant. Biomagnification means the increase in amount of DDT in the body of organism along with the increase in trophic level. Hence, the amount of DDT in 1st trophic level will be minimum and in top consumer will be maximum.
DNA polymerase enzyme is required for synthesis of
DNA from RNA
RNA from DNA
DNA from DNA
RNA from RNA
C.
DNA from DNA
The enzyme needed for replication of DNA i.e. formation of DNA from DNA is DNA polymerase III. DNA replication is initiated by RNA primer which is later removed by DNA polymerase I.
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.
Which type of DNA is found in bacteria
Helical DNA
Membrane bound DNA
Straight DNA
Circular free DNA
D.
Circular free DNA
Bacteria are prokaryotic in nature, in which typical chromosomes are lacking. DNA is circular and naked as it is not surrounded by histones (basic proteins which are responsible for coiled structure of nucleosome).
The part of earth in which life exist is known as
Lithosphere
Biosphere
Atmosphere
Hydrosphere
B.
Biosphere
Biosphere is the part of earth where life exists.
2n-1 condition represent
tetrasomy
trisomy
monosomy
multisomy
C.
monosomy
When changes involve only a few chromosome say one or two and not the entire genome, the phenomenon is called aneuploidy. Monosomy is a case of aneuploidy, when there is loss of one chromosome from a pair of homologue.
In terrestrial ecosystem such as forest, maximum energy is found in which trophic level
T1
T2
T3
T4
A.
T1
In almost all ecosystem the maximum amount of energy is found in 1st trophic level.
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.