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Which of the following is not a feature of the double helix model of DNA ?
- a)The two chains have anti-parallel polarity
- b)A purine always comes opposite to a pyrimidine
- c)The pitch of the DNA is 3.4 nm
- d)The two chains are coiled in a left-handed fashion
Correct answer is option 'D'. Can you explain this answer?
Verified Answer
Which of the following is not a feature of the double helix model of D...
The two chains are coiled in a right handed fashion.
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Which of the following is not a feature of the double helix model of D...
Understanding the Double Helix Model of DNA
The double helix model of DNA is a fundamental concept in molecular biology, describing the structure and function of deoxyribonucleic acid. Here’s a breakdown of the key features of this model and the incorrect statement regarding its characteristics.
1. Anti-Parallel Polarity
- The two strands of DNA run in opposite directions, which is referred to as anti-parallel polarity.
- One strand runs from the 5' to 3' direction, while the complementary strand runs from 3' to 5'.
2. Base Pairing
- In the double helix, a purine (adenine or guanine) pairs with a pyrimidine (thymine or cytosine) through hydrogen bonds.
- This specific pairing (A-T and G-C) is crucial for the stability of the DNA structure.
3. Pitch of the DNA Helix
- The pitch of the DNA helix is approximately 3.4 nanometers.
- This measurement represents the distance for one complete turn of the helix, which is about 10 base pairs.
4. Right-Handed Helix
- The correct structure of DNA is a right-handed helix, not a left-handed one.
- This means that as the helix twists, it spirals to the right, which is a critical aspect of its physical properties and biological functions.
Conclusion
The statement "The two chains are coiled in a left-handed fashion" is incorrect. The double helix of DNA is indeed right-handed, making option D the answer to the question. Understanding these characteristics is essential for comprehending how DNA functions in biological systems.
The double helix model of DNA is a fundamental concept in molecular biology, describing the structure and function of deoxyribonucleic acid. Here’s a breakdown of the key features of this model and the incorrect statement regarding its characteristics.
1. Anti-Parallel Polarity
- The two strands of DNA run in opposite directions, which is referred to as anti-parallel polarity.
- One strand runs from the 5' to 3' direction, while the complementary strand runs from 3' to 5'.
2. Base Pairing
- In the double helix, a purine (adenine or guanine) pairs with a pyrimidine (thymine or cytosine) through hydrogen bonds.
- This specific pairing (A-T and G-C) is crucial for the stability of the DNA structure.
3. Pitch of the DNA Helix
- The pitch of the DNA helix is approximately 3.4 nanometers.
- This measurement represents the distance for one complete turn of the helix, which is about 10 base pairs.
4. Right-Handed Helix
- The correct structure of DNA is a right-handed helix, not a left-handed one.
- This means that as the helix twists, it spirals to the right, which is a critical aspect of its physical properties and biological functions.
Conclusion
The statement "The two chains are coiled in a left-handed fashion" is incorrect. The double helix of DNA is indeed right-handed, making option D the answer to the question. Understanding these characteristics is essential for comprehending how DNA functions in biological systems.
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Which of the following is not a feature of the double helix model of DNA ?a)The two chains have anti-parallel polarityb)A purine always comes opposite to a pyrimidinec)The pitch of the DNA is 3.4 nmd)The two chains are coiled in a left-handed fashionCorrect answer is option 'D'. Can you explain this answer? for NEET 2026 is part of NEET preparation. The Question and answers have been prepared according to the NEET exam syllabus. Information about Which of the following is not a feature of the double helix model of DNA ?a)The two chains have anti-parallel polarityb)A purine always comes opposite to a pyrimidinec)The pitch of the DNA is 3.4 nmd)The two chains are coiled in a left-handed fashionCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for NEET 2026 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Which of the following is not a feature of the double helix model of DNA ?a)The two chains have anti-parallel polarityb)A purine always comes opposite to a pyrimidinec)The pitch of the DNA is 3.4 nmd)The two chains are coiled in a left-handed fashionCorrect answer is option 'D'. Can you explain this answer?.
Which of the following is not a feature of the double helix model of DNA ?a)The two chains have anti-parallel polarityb)A purine always comes opposite to a pyrimidinec)The pitch of the DNA is 3.4 nmd)The two chains are coiled in a left-handed fashionCorrect answer is option 'D'. Can you explain this answer? for NEET 2026 is part of NEET preparation. The Question and answers have been prepared according to the NEET exam syllabus. Information about Which of the following is not a feature of the double helix model of DNA ?a)The two chains have anti-parallel polarityb)A purine always comes opposite to a pyrimidinec)The pitch of the DNA is 3.4 nmd)The two chains are coiled in a left-handed fashionCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for NEET 2026 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Which of the following is not a feature of the double helix model of DNA ?a)The two chains have anti-parallel polarityb)A purine always comes opposite to a pyrimidinec)The pitch of the DNA is 3.4 nmd)The two chains are coiled in a left-handed fashionCorrect answer is option 'D'. Can you explain this answer?.
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