CBSE(NCERT) GRADE 12 BIOLOGY 2022 SET1

Which one of the two biogas plants can be used for generating gas fuel and electricity and why? Give suitable reasons in support of your answer.

Explain the two physiological attributes which enable a kangaroo rat to survive in desert conditions.

Study the given graphs (X) and (Y) depicting the annual variation in solar radiation on Earth from January to December and answer the undermentioned questions. (i) Identify the graph that depicts (I) tropical region, and (II) temperate region, respectively. (ii) Which of the two regions, (X) or (Y), will show high biological diversity and why? Give two reasons.

When Plasmodium sp. (malarial parasite) enters the human body, it reproduces asexually and increases its number. During this course, the affected person suffers from malaria. After a number of asexual cycles, the parasite, in order to complete its life cycle, enters the sexual phase of its life. Trace the sexual stages in the life cycle of Plasmodium in a female Anopheles mosquito, when it bites an infected person, up to the formation of mature infective stages of the parasite.

A large proportion of infants remain free from potent infections at least three months after birth, or even longer if breast fed. Explain, giving suitable reasons.

(i) How has the introduction of Nile Perch into Lake Victoria in East Africa had a devastating effect on the indigenous species in the lake? (ii) Name two invasive weed species which have posed a threat to the existence of our native species.

With the advent of sophisticated techniques of genetic engineering, we can now readily purify and isolate DNA. Name and explain the different steps involved in the separation and isolation of DNA fragments once cut by restriction endonucleases.

In an ecosystem, some species (species) affect the main functions of the ecosystem more than other species. How did Paul Ehrlich explain this by his 'rivet' hypothesis?

Development of recombinant DNA technology has opened gates to many breakthroughs in the fields of medicine and agriculture. This has enabled scientists to isolate, sequence and manipulate individual genes obtained from diverse living or dead cells. Given below is a diagram showing the basic steps involved in genetically modifying an organism. Study the given diagram and answer the questions that follow: (i) Are two different types of restriction endonucleases used, one to cut the vector DNA and another to cut the desired DNA to be cloned? Support your answer, giving reason. (ii) Which enzyme is used at step (X) to integrate the foreign DNA with the vector DNA? (iii) What is the term used for step (Y) showing multiple copies of the foreign DNA being formed in transformed E. coli? (iv) Draw a diagram of E. coli cloning vector pBR322 to show the following: (I) Any one restriction endonuclease site in tetracycline resistance gene (II) Any one restriction endonuclease site in ampicillin resistance gene (III) (v) What does rop code for in plasmid pBR322?

Are two different types of restriction endonucleases used, one to cut the vector DNA and another to cut the desired DNA to be cloned? Support your answer, giving reason.

An application of biotechnology in agriculture involves production of

Which enzyme is used at step (X) to integrate the foreign DNA with the vector DNA?

What is the term used for step (Y) showing multiple copies of the foreign DNA being formed in transformed E. coli?

Draw a diagram of E. coli cloning vector pBR322 to show the following: (I) Any one restriction endonuclease site in tetracycline resistance gene (II) Any one restriction endonuclease site in ampicillin resistance gene (III)

What does rop code for in plasmid pBR322?

What do you interpret from the bars (X and Z) obtained after 264 hours of treatment of monkeys with saline and 2.5 mg/kg SiRNAs treatment?

Name the category of organisms in the living world, where RNA interference (RNAi) takes place. Why?

What is the basic principle involved in RNA interference (RNAi) in silencing the preferred genes?