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Chargaff's rule states that in an organism          [2003]
  • a)
    Amounts of all bases are equal
  • b)
    Amount of adenine (A) is equal to that ofthymine (T) and the amount of guanine (G)is equal to that of cytosine (C)
  • c)
    Amount of adenine (A) is equal to that ofguanine (G) and the amount of thymine (T)is equal to that of cytosine (C)
  • d)
    Amount of adenine (A) is equal to that ofcytosine (C) and rthe amount of thymine (T)is equal to that of guanine (G)
Correct answer is option 'B'. Can you explain this answer?
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Chargaff's rule states that in an organism [2003]a)Amounts of ...
Amount of A = T and that of G = C.
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Chargaff's rule states that in an organism [2003]a)Amounts of ...
The ratio between adenine (A) and thymine (T) and guanine (G) and cytosine(C) are constant and equal
A/T +G/C=1
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Chargaff's rule states that in an organism [2003]a)Amounts of ...
Chargaff's Rule

Chargaff's rule, also known as the base-pairing rule, states that in the DNA of an organism, 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, an Austrian-American biochemist, in the late 1940s.

Explanation

Chargaff's rule is based on the complementary base pairing in DNA. DNA is made up of two strands that are twisted together to form a double helix. Each strand consists of a backbone made of sugar and phosphate molecules, with bases attached to the sugar molecules. The bases can be adenine (A), thymine (T), guanine (G), or cytosine (C).

The bases in DNA form specific pairs through hydrogen bonding: adenine pairs with thymine, and guanine pairs with cytosine. This means that for every adenine molecule in a DNA strand, there is a thymine molecule in the opposite strand, and for every guanine molecule, there is a cytosine molecule.

Chargaff's rule states that the amounts of adenine and thymine are always equal in DNA, as are the amounts of guanine and cytosine. This can be explained by the complementary base pairing. If the amount of adenine were not equal to the amount of thymine, the DNA strands would not be able to pair properly, leading to structural instability. Similarly, if the amount of guanine were not equal to the amount of cytosine, the DNA strands would not be able to pair properly.

Significance

Chargaff's rule is important in understanding the structure and function of DNA. It provides a fundamental principle for the replication of DNA during cell division, as the complementary base pairing allows each DNA strand to serve as a template for the synthesis of a new strand.

Furthermore, Chargaff's rule has practical applications in various fields of biology and genetics. It can be used in DNA sequencing techniques to determine the base composition of a DNA molecule. It is also useful in forensic science, where the comparison of DNA profiles relies on the principle of base pairing.

In conclusion, Chargaff's rule states that in the DNA of an organism, the amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine. This rule is based on the complementary base pairing in DNA and has significant implications for DNA structure, replication, and various applications in biology and genetics.
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Chargaff's rule states that in an organism [2003]a)Amounts of all bases are equalb)Amount of adenine (A) is equal to that ofthymine (T) and the amount of guanine (G)is equal to that of cytosine (C)c)Amount of adenine (A) is equal to that ofguanine (G) and the amount of thymine (T)is equal to that of cytosine (C)d)Amount of adenine (A) is equal to that ofcytosine (C) and rthe amount of thymine (T)is equal to that of guanine (G)Correct answer is option 'B'. Can you explain this answer?
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