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प्रश्न
Which property of DNA double helix led Watson and Crick to hypothesise semi-conservative mode of DNA replication? Explain.
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उत्तर
Watson and Crick proposed a semi-conservative mode of DNA replication based on the molecule's antiparallel, double-stranded structure. They suggested that the two strands of the DNA molecule uncoil and separate, with each strand serving as a template for the production of a new (complementary) strand alongside it. The template and its complement then combine to generate a new double strand of DNA that is identical to the original molecule. The sequence of bases that should be present in the new strands is easily predicted because they will be complementary to the bases present in the old strands. A will partner with T, T with A, C with G, and G with C. As a result, two daughter DNA molecules are created that are identical to the parent molecule; each daughter DNA molecule is made up of one new and one old strand. This replication mechanism is referred to as semi-conservation since each daughter molecule only contains one conserved parent strand. Later, experiments by Joseph Taylor, Meselson and Stahl verified it.
संबंधित प्रश्न
Group the following as nitrogenous bases and nucleosides:
Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine.
Chargaff’s rules are applicable to ______.
One turn of DNA possesses ______.
If a double stranded DNA has 20% of cytosine, what will be the percentage of adenine in it?
In some viruses, RNA is present instead of DNA indicating that ______.
In a DNA strand the nucleotides are linked together by ______.
Both deoxyribose and ribose belong to a class of sugars called ______.
The fact that a purine base always paired through hydrogen bonds with a pyrimidine base leads to, in the DNA double helix ______.
What is the nature of the strands of the DNA duplex?
Protein helping in opening of DNA double helix in front of replications fork is ______.
How far is each base pair from the next one in DNA double helix model?
Synthesis of DNA from RNA is explained by ______.
H-bonds between Cytosine and Guanine are ______.
DNA is made of two chains that twist about one another in the shape of a ______.
______ occurs in RNA instead of the nitrogenous base thymine found in DNA.
Which of the following is a purine?
During in vitro synthesis of DNA, a researcher used 2’, 3’ – dideoxy cytidine triphosphate as raw nucleotide in place of 2’-deoxy cytidine. What would be the consequence?
A short piece of DNA, having 20 base pairs, was analyzed to find the number of nucleotide bases in each of the polynucleotide strands. Some of the results are shown in the table.
| Number of nucleotide bases | ||||
| Adenine | Cytosine | Guanine | Thymine | |
| Strand 1 | 4 | 4 | ||
| Strand 2 | 5 | |||
How many nucleotides containing Adenine were present in strand 2?
What is the smallest part of a DNA molecule that can be changed by a point mutation?
