Structure of DNA - Lecture 2 Flashcards
What are the two roles of genes?
○ Units of biological information
○ Units of inheritance
What are the monomers of DNA called?
Nucleotides
What are the three parts of each nucleotide?
○ Sugar = 2’ deoxyribose
○ Phosphate group
○ Base
How many phosphate groups are attached and where is it attached?
○ 1 to 3 attached to a sugar on the 5’ carbon
○ α = closest
○ γ = furthest
What carbon is the base attached to and how?
○ 1’ carbon
○ Attached to sugar with a β-N-glycosidic bond
What are the purines?
○ Adenine
○ Guanine
What are the pyrimidines?
○ Cytosine
○ Thymine
What is Chargaff’s rule?
Total number of purines in a DNA molecule is equal to the total number of pyrimidines
How are nucleotides joined together?
Phosphodiester bond
What is the direction of DNA?
5’ -> 3’
Who discovered the double helix structure?
James Watson and Francis Crick
What are the features of the DNA double helix?
○ Two strands are anti-parallel
○ There is a major and minor groove
○ The two strands are held together by base-pairing (hydrogen bonds)
What is the GC content of human DNA?
40.3%
What is the GC content of plasmodium falciparum (causes malaria)?
19%
What is the GC content of soil bacteria?
72.4%
