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प्रश्न
Answer the following question in your own words.
Describe the structure of the DNA molecule.
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उत्तर
- All organisms have the same DNA structure. Watson and Crick modelled DNA in 1953. In this model, two parallel nucleotide threads coil around each other. A ‘double helix’ describes this arrangement. Like a coiled ladder, its construction is flexible.
- The DNA strands include many tiny ‘nucleotide’ molecules. Four nitrogenous bases are adenine, guanine, cytosine, and thymine. Cytosine and thymine are pyrimidines and adenine and guanine are purines.
- A nitrogenous base, phosphoric acid, and sugar molecule form the nucleotide.
- Four types of nitrogenous bases equal four types of nucleotides.
- DNA has a chain of nucleotides. Each ladder rail is constructed of alternately connected sugar and phosphoric acid molecules, like the DNA molecule's two threads. Every ladder step is two nitrogenous bases connected by hydrogen bonds. Adenine always connects with thymine, cytosine with guanine.
Structure of DNA
DNA (Watson and Crick’s Model)
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संबंधित प्रश्न
Correct the following statement by changing the underlined word:
Nitrogen bonds are present between the complementary nitrogenous bases of DNA.
The three sketch (A, B and C) are intended to represent the replication of DNA.
What should be their correct sequence, starting with the first and ending with the last? ……
State whether the following sentence is true or false:
Each spiral of the DNA has 12 nucleotides.
Choose the correct answer:
Sex chromosomes in man are _____________
Multiple Choice Question
DNA structure was discovered by:
How many codons are needed to specify three amino acids?
What is the name given to the segments of DNA, which are responsible for the inheritance of a particular character?
How is the structure of DNA organized?
What is the biological significance of DNA?
In glycolysis how many NADH molecules are produced during the conversion of one glucose molecule to yield two molecules of pyruvate?
A DNA strand with the sequence AACGTAACG is transcribed. What is the sequence of the mRNA molecule synthesized?
Which of the following best describes the structural difference between a nucleoside and a nucleotide?
Nitrogenous bases in DNA are classified into two categories based on ring structure. Which bases belong to the purine class?
Which nitrogenous bases are classified as pyrimidines, characterized by their single-ringed structure?
Which structural component of DNA is hydrophilic and located on the exterior of the double helix?
What is the diameter of the DNA double helix as proposed by Watson and Crick?
Bacteriophage λ (lambda) has a genome of approximately how many base pairs?
Bacteriophage φX174 is notable for having one of the smallest known viral genomes. Approximately how many nucleotides does it contain?
