Which is true according to Chargaff’s rule ?a)A G = T Cb)A = Cc)G = Td...
Chargaff rule says that the no. of purines should be equal to no. of pyrimidines
Which is true according to Chargaff’s rule ?a)A G = T Cb)A = Cc)G = Td...
Chargaff's rule, also known as the base pairing rule, states that in a DNA molecule, the amount of adenine (A) is equal to the amount of thymine (T), and the amount of guanine (G) is equal to the amount of cytosine (C). This rule was discovered by Erwin Chargaff in the early 1950s and played a crucial role in the understanding of DNA structure and function.
The correct answer to the question is option 'A' - A G = T C. This means that the amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine in a DNA molecule.
Explanation:
- DNA Structure:
- DNA is a double-stranded molecule that resembles a twisted ladder or a helix. The two strands are held together by hydrogen bonds between the base pairs.
- The four nitrogenous bases present in DNA are adenine (A), thymine (T), guanine (G), and cytosine (C).
- Complementary Base Pairing:
- Adenine always pairs with thymine, and guanine always pairs with cytosine.
- These base pairs form the rungs of the DNA ladder, with the sugar-phosphate backbone forming the sides.
- Chargaff’s Rule:
- Erwin Chargaff analyzed the composition of DNA from various organisms and made an important observation.
- He found that the amount of adenine is always equal to the amount of thymine in a DNA molecule, and the amount of guanine is always equal to the amount of cytosine.
- This means that the base pairs are always present in a 1:1 ratio.
- Significance of Chargaff’s Rule:
- Chargaff’s rule played a crucial role in understanding the structure of DNA and contributed to the discovery of the double helix model by Watson and Crick.
- It provided evidence for the specific pairing of the DNA bases and helped explain how DNA could replicate itself accurately.
- The base pairing rule also has important implications in DNA sequencing and genetic research.
In conclusion, Chargaff's rule states that the amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine in a DNA molecule. This rule is fundamental to the understanding of DNA structure and function.
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