Chargaff's Rules exam Flashcards
BackRelated flashcards
Related practice sets
More sets
Terms in this set (29)
Chargaff's First Rule
DNA base composition varies among species.
Chargaff's Second Rule
In any given species, the amount of adenine (A) is roughly equal to thymine (T), and the amount of guanine (G) is roughly equal to cytosine (C).
What did Chargaff discover about DNA base composition?
He discovered that DNA base composition varies among different species.
Why are the percentages of A and T roughly equal in DNA?
Because adenine (A) pairs with thymine (T) through complementary base pairing.
What is the significance of complementary base pairing?
It is crucial for the storage and transmission of genetic information.
What did Chargaff's rules help to reveal?
The double helix structure of DNA.
How did Chargaff's findings impact the understanding of DNA?
They highlighted the importance of complementary base pairing in DNA structure.
What are the four nitrogenous bases in DNA?
Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).
What is the base pairing rule in DNA?
Adenine (A) pairs with Thymine (T), and Guanine (G) pairs with (Cytosine) C.
Why are the percentages of G and C roughly equal in DNA?
Because guanine (G) pairs with cytosine (C) through complementary base pairing.
What did Chargaff's data table show?
The DNA composition in different species, showing varying percentages of A, T, G, and C.
What species did Chargaff study to determine his rules?
Various species, including Homo sapiens (humans) and Escherichia coli.
What was unknown about DNA in the early 1950s?
The structure of DNA.
How did Chargaff's techniques affect his findings?
Limitations in his techniques caused slight discrepancies in the exact percentages of A, T, G, and C.
What is the approximate percentage of A and T in human DNA?
Approximately 31%.
What is the approximate percentage of G and C in human DNA?
Approximately 19%.
Why are Chargaff's rules important?
They were crucial for understanding the structure and function of DNA.
What does complementary base pairing ensure?
The accurate replication and transmission of genetic information.
What did Chargaff's findings suggest about DNA structure?
That DNA has a specific pairing mechanism between its bases.
What is the significance of the equal percentages of A and T, and G and C?
It supports the idea of complementary base pairing in the DNA double helix.
What did Chargaff's rules contribute to molecular biology?
They provided foundational knowledge for the discovery of DNA's double helix structure.
What is the role of nitrogenous bases in DNA?
They form the rungs of the DNA ladder through base pairing.
How did Chargaff's discoveries influence future research?
They guided scientists towards understanding the molecular structure of DNA.
What is the relationship between DNA base composition and species?
Different species have different DNA base compositions.
What did Chargaff's data reveal about DNA in different species?
That the percentages of A, T, G, and C vary among species but follow specific pairing rules.
What is the importance of Chargaff's second discovery?
It indicated that DNA has a consistent base pairing mechanism across different species.
What did Chargaff's rules help to establish in genetics?
The principle of complementary base pairing in DNA.
What was a limitation in Chargaff's research techniques?
They caused slight inaccuracies in the exact percentages of DNA bases.
What is the significance of the percentages of A, T, G, and C in DNA?
They are crucial for understanding DNA's structure and function.