Biology:2016:CBSE:[All India]:Set-III

Following are two advantages of preferring CNG over diesel as an automobile fuel:

• Unlike diesel, CNG burns most efficiently and very little of it is left in the automobiles.
• CNG is cheaper than diesel.

Transgenic animals are those animals that have their DNA manipulated to possess and express an extra (foreign) gene. An example of transgenic animal is transgenic rat.

Evidence shows that Homo habilis essentially ate fruit and did not eat meat while Homo erectus probably ate meat.

In MOET, the genetic mother is administered with FSH (Follicle stimulating hormone) to stimulate the production of many eggs for super ovulation. This results in the production of 6-8 eggs per cycle instead of one.

A Male honeybee develops from an unfertilised egg by the process of parthenocarpy, while a female honey bee develops from the fertilised egg. Therefore, male honey bee has 16 chromosomes, while a female honey bee has 32 chromosomes (16+16).

Free-living bacterium: Azospirillum

Symbiotic bacterium: Rhizobium

They are called biofertilisers because they naturally enrich the nutrients of a soil.

When a HIV virus infects a human body, it firstly enters the macrophages, where RNA genome of a virus replicates to form a viral DNA with the help of an enzyme reverse transcriptase. The viral DNA gets incorporated into host cell’s DNA and directs the infected cell to produce the virus particles. The macrophages continue to produce virus and act like a HIV factory. Simultaneously, HIV enters the helper T-lymphocytes (T_H), where it replicates and produces progeny viruses. The progeny viruses, which are released in the blood, attack other helper T lymphocytes. It results in progressive decrease in the number of helper T lymphocytes of an infected person, which thereby reduces the immunity of a person.

The ultra violet rays emitted from the sun, strike CFC molecules present in the environment. As a result, CFC molecules are broken down and chlorine atoms are released. A free chlorine atom binds to ozone molecule and releases single oxygen atom. It leads to the depletion of ozone layer in the stratosphere.

Sacred groves are patches of trees on forest land, which are protected communally since ages. They are highly protected due to religious and cultural traditions. Sacred groves provide refuges to a large number of rare and threatened plants. These are ecologically unique regions with rich biodiversity.

Stop codon indicates no code for any amino acid.

Unambiguous codon indicates one codon codes for only one amino acid.

Degenerate codon indicates one codon codes for more than one amino acid.

Universal codon indicates that codon is nearly same for all either human or bacteria.