CBSE Class 12 Biology Question Paper 2006

CBSE CLASS XII Questions

• 1.

  The process of copying genetic information from template strand of DNA into RNA is called transcription. It is mediated by RNA polymerase. Transcription takes place in the nucleus of eukaryotic cells. In transcription, only a segment of DNA and only one of the strands is copied into RNA. 

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• 2.

  Explain Gause’s 'Competitive Exclusion Principle' and provide a suitable ecological example that demonstrates this principle in nature.

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• 3.

  We know that plasmids and bacteriophages are the most commonly used vectors in biotechnology experiments. If we can link an alien piece of DNA to the plasmid DNA, the alien DNA can be multiplied equal to the copy number of the plasmid. Engineered vectors are used these days. Study the diagram of the E. coli cloning vector pBR322 and answer the questions that follow : 

  

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• 4.

  Explain the different organizational levels of biodiversity at the genetic, species, and ecological levels, providing a suitable example for each category.

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• 5.

  Briefly explain the events of fertilisation and implantation in an adult human female.

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• 6.

  Study the given chart showing evolution of plants. Answer the following questions :