Science (English Medium) Class 12 - CBSE Question Bank Solutions for Biology

What are the methods of cancer detection? Describe the common approaches for treatment of cancer.

Why is a malignant tumour considered to be more damaging than a benign tumour? Explain.

One of the major approaches of crop improvement programme is Artificial Hybridisation. Explain the steps involved in making sure that only the desired pollen grain pollinate the stigma of a bisexual flower by a plant breeder. 

Name any two techniques used to detect the cancer of internal organs and write about any one of them.

Immunotherapy these days is one of the most efficient ways of treatment of cancer. The therapy involved activates the immune system and destroys the tumour.

1. Write an example of one such biological response modifier used in immunotherapy.
2. Why do patients need such substances if immune system is already working in body?
3. State what is 'Contact inhibition'.

Variations caused due to mutations are ______.

Suggest how pedigree analysis can be useful?

Depending upon the chemical nature of the template (DNA or RNA) and the nature of nucleic acids synthesised from it (DNA or RNA), list the types of nucleic acid polymerases.

Differentiate between the following:

mRNA and tRNA

Explain the process of transcription in Eukaryotes.

Explain the process of making heterogeneous nuclear RNA (hnRNA) into a fully functional mRNA in eukaryotes. Where does this process occur in the cell?

Answer the following question.
Construct and label a transcription unit from which the RNA segment given below has been transcribed. Write the complete name of the enzyme that transcribed this RNA. 

With regard to mature mRNA in eukaryotes.

Regulatory proteins are the accessory proteins that interact with RNA polymerase and affect its role in transcription. Which of the following statements is correct about regulatory protein?

Methyl guanosine triphosphate is added at 5' end of hn-RNA in a process of ______.

If the base sequence of a codon in mRNA is 5'-AUG-3', the sequence of tRNA pairing with it must be ______.

The amino acid attaches to the tRNA at its ______.

To initiate translation, the mRNA first binds to ______.

In transcription in eukaryotes, heterogeneous nuclear RNA (hnRNA) is transcribed by ______.

In eukaryotes, the process of processing of primary transcript involves ______.