Advertisements
Advertisements
Question
Which property of DNA double helix led Watson and Crick to hypothesise semi-conservative mode of DNA replication? Explain.
Advertisements
Solution
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-stranded DNA molecule identical to the original. 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 consists of one new and one old strand. This replication mechanism is referred to as semi-conservation because each daughter molecule contains only one conserved parent strand. Later, experiments by Joseph Taylor, Meselson and Stahl verified it.
APPEARS IN
RELATED QUESTIONS
Group the following as nitrogenous bases and nucleosides:
Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine.
If a double stranded DNA has 20 per cent of cytosine, calculate the per cent of adenine in the DNA.
One turn of DNA possesses ______.
In a DNA strand the nucleotides are linked together by ______.
A nucleoside differs from a nucleotide. It lacks the ______.
Who amongst the following scientists had no contribution in the development of the double helix model for the structure of DNA?
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 ______.
If 30 percent of an organism’s DNA is thymine, then ______.
H-bonds between Cytosine and Guanine are ______.
______ occurs in RNA instead of the nitrogenous base thymine found in DNA.
In the polynucleotide chain of DNA, a nitrogenous base is linked to the -OH of ______
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?
A nucleotide is the monomer unit of a nucleic acid. Which of the following correctly identifies the three components of a nucleotide?
The phosphate group in a nucleotide is attached to which carbon of the pentose sugar?
In a polynucleotide chain, nucleotides are linked together by which type of bond?
In a DNA double helix, what is the spatial relationship between the two polynucleotide strands?
Why is the name 'deoxyribonucleic acid' appropriate for DNA?
A dinucleotide is formed by linking two nucleotides together. The bond formed between them is:
Pyrimidines differ from purines in their basic structural feature. Which statement is correct?
A nucleotide is the monomer unit of a nucleic acid. Which of the following correctly identifies the three components of a nucleotide?
Which of the following nitrogenous bases is classified as a purine with a double-ring structure?
The 3′ end of a polynucleotide chain is characterized by the presence of:
The backbone of a polynucleotide chain is formed by which components?
In a DNA double helix, what is the spatial relationship between the two polynucleotide strands?
What is the significance of the 2′-OH group in ribose compared to deoxyribose?
A dinucleotide is formed by linking two nucleotides together. The bond formed between them is:
