Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Biology

Mention the different ways by which the population density of different species can be measured.

Name the microbes that help the production of the following product commercially:
Statin

Name the microbes that help the production of the following product commercially:
Penicillin

The net electric charge on DNA and histones is ______.

Nucleosome core is made of ______.

Barr body in mammals represents ______.

Histone proteins are ______.

The structure in chromatin seen as ‘beads-on string’ when viewed under electron microscope are called ______.

Find out the wrong statement about heterochromatin.

Which of the following is correct about mature RNA in eukaryotes?

The total number of nucleotide sequences of DNA that code for a hormone is 1530. The proportion of different bases in the sequence is found to be Adenine = 34%, Guanine = 19%, Cytosine = 23%, Thymine = 19%.

Applying Chargaff’s rule, what conclusion can be drawn?

A stretch of euchromatin has 200 nucleosomes. How many bp will there be in the stretch and what would be the length of the typical euchromatin? 

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In prokaryotes, DNA is circular and present in the cytoplasm but in eukaryotes, DNA is linear and mainly confined to the nucleus. DNA or deoxyribonucleic acid is a long polymer of nucleotides. In 1953, the first correct double-helical structure of DNA was worked out by Watson and Crick. Based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin. It is composed of three components, i.e., A phosphate group, a deoxyribose sugar, and a nitrogenous base. Different forms of DNA are B-DNA, Z-DNA, A-DNA, C-DNA, and D-DNA.

Name the linkage present between the nitrogen base and pentose sugar in DNA.

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In prokaryotes, DNA is circular and present in the cytoplasm but in eukaryotes, DNA is linear and mainly confined to the nucleus. DNA or deoxyribonucleic acid is a long polymer of nucleotides. In 1953, the first correct double-helical structure of DNA was worked out by Watson and Crick. Based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin. It is composed of three components, i.e., A phosphate group, a deoxyribose sugar, and a nitrogenous base. Different forms of DNA are B-DNA, Z-DNA, A-DNA, C-DNA, and D-DNA.

The double helix structure of DNA was proposed by ______ 

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In prokaryotes, DNA is circular and present in the cytoplasm but in eukaryotes, DNA is linear and mainly confined to the nucleus. DNA or deoxyribonucleic acid is a long polymer of nucleotides. In 1953, the first correct double-helical structure of DNA was worked out by Watson and Crick. Based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin. It is composed of three components, i.e., A phosphate group, a deoxyribose sugar, and a nitrogenous base. Different forms of DNA are B-DNA, Z-DNA, A-DNA, C-DNA, and D-DNA.

The double chain of B-DNA is coiled in a helical fashion. The spiral twisting of the B-DNA duplex produces ______ 

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The process of copying genetic information from the 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.

Monocistronic structural genes are found in which organisms?

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The translation is the process of polymerization of amino acids to form a polypeptide. The order and sequence of amino acids are defined by the sequence bases in the mRNA. The amino acids are joined by a bond called a peptide bond. The ribosome is the site of protein synthesis.

During translation, how many initiation factors are required in eukaryotes for initiation reactions?

Which of the below mentioned regions exhibit lees seasonal variations?

What is the function of histones in DNA packaging?

Distinguish between heterochromatin and euchromatin. Which of the two is transcriptionally active?