2. The Magic Double Helical Structure of DNA Flashcards
What did Friedrich Miescher do?
Isolated nuclein (DNA) for the first time
What are the building blocks of DNA?
Sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base. 4 bases (A, C, G, T).
What is the difference between the sugars in RNA and DNA?
RNA contains the sugar ribose, while DNA contains the slightly different sugar deoxyribose (a type of ribose that lacks one oxygen atom),
What is the difference between Nucleoside and Nucleotide?
Nucleotides consist of the components such as a nitrogenous base, sugar, and a phosphate group while the nucleosides contain only sugar and a base. The nucleotide forms the basic structure of RNA and DNA, while the nucleoside occurs before the nucleotide itself.
What did Phoebe Levine theory state?
Levene identified the building blocks of DNA, including the four bases. Levene thought that DNA was linked in a linear fashion and that A=C=G=T. However, this model is incorrect and if it were true, the DNA structure would be too simple to contain genetic material.
What did Chargaff’s rule prove about Levine’s theory?
Chargaffs proved that Levine’s A=C=G=T was incorrect. Found that DNA, either found in plant/animals, had equal amounts of A, T and equal amounts of C, G.
Is the composition of DNA the same in all species?
No, the ratio of genetic material, particularly the amount of A,C T,G bases differs from specie to specie.
What is the significance of Rosalind Franklin and Wilkins X-ray analyses?
They demonstrated that DNA has a regularly repeating helical structure?
What are the types of DNA?
A, B, and Z. A form is found in low humidity, B form found in high humidity, and Z form is Z because the backbone is in a zigzag formation.
What is the diameter of the helix?
2 nm (nanometer) = 20 A
