DNA precipitation out of a mixture of biomolecules can be achieved by treatment with

• Chilled ethanol

• Methanol at room temperature

• Chilled chloroform

• Isopropanol

Variations caused by mutation, as proposed by Hugo de Vries are

• random and directionless

• small and directional

• small and directionless

• random and directional

The Earth Summit held in Rio de Janeiro in 1992 was called

• for conservation of biodiversity and sustainable utilization of its benefits

• to assess threat posed to native species by invasive weed species

• for immediate steps to discontinue use of CFCs that were damaging the ozone layer

• to reduce CO₂ emissions and global warming

Which of the following pairs of gases is mainly responsible for green house effect?

• Oxygen and nitrogen

• Nitrogen and Sulphur dioxide

• Carbon dioxide and Methane

• Ozone and Ammonia

Which of the following can be used as a biocontrol agent in the treatment of plant disease?

• Chlorella

• Anabaena

• Lactobacillus

• Trichoderma

Which of the following immune responses is responsible for rejection of kidney graft?

• Humoral immune response

• Inflammatory immune response

• Cell-mediated immune response

• Auto-immune response

Polyblend, a fine powder of recycled modified plastic, has proved to be a good material for

• used as a fertilizer

• Construction of roads

• Making tubes and pipes

• Making plastic sacks

The frequency of recombination between gene pairs on the same chromosome as a measure of the distance between genes was explained by :

• Gregor J. Mendel

• Alfred Sturtevant

• Sutton Boveri

• T.H. Morgan

Identify the correct pair representing the causative agent of typhoid fever and the confirmatory test for typhoid.

• Streptococcus pneumoniae / Widal test

• Salmonella typhi / Anthrone test

• Salmonella typhi / Widal test

• Plasmodium vivax / UTI test

Match the following genes of the Lac operon with their respective products :

Select the correct option

• A - (iii); B - (i); C - (ii); D - (iv)

• A - (iii); B - (i); C - (iv); D - (ii)

• A - (iii); B - (i); C - (i); D - (ii)

• A - (i); B - (iii); C - (ii); D - (iv)