Biology 1202B Lecture Notes - Lecture 11: Nucleoside Triphosphate, The Double Helix, Nobel Peace Prize
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Lecture 11: DNA Structure and Organization
Human Genome
1952 – Hershey & Chase – discovered DNA inherited material
1953 – Watson, Crick & Franklin – discovered the DNA structure double helix
1956 – Tijo & Levan – found there were 46 linear chromosomes in the nucleus
1963 – Margit & Sylvan Nass – discovered circular chromosomes in mitochondria
DNA Structure
Watson and Crick won a Nobel peace prize for discovering the double helix structure
of DNA
Rosalind Franklin played an indirect role in this discovery because she actually
discovered the helix by x-ray diffraction. However, she died at a young age from
exposure to the substances she was working with. Her reports made their way to
Watson and Crick.
Nucleotides
Nucleotides are the building blocks of nucleic
acids
A nucleic acid is composed of a phosphate
group, a pentose (5) sugar, and a nitrogenous
base
These three basic components stay constant in
nucleic acids but can differ in many other ways
Differences between RNA and DNA
1. Ribose Sugar – DNA lacks an OH
2. Thymine (T) and Uracil (U)
3. Strand – DNA = double stranded
- RNA = single stranded
DNA
Phosphate group
Deoxyribose Sugar
4 nitrogenous bases:
o Guanine (G)
o Adenine (A)
o Thymine (T)
o Cytosine (C)
RNA
A phosphate group
Ribose Sugar
4 nitrogenous bases
o Guanine (G)
o Adenine (A)
o Uracil (U)
o Cytosine (C)
DNA & RNA are both made of dNTP – (deoxynucleoside triphosphate)
Ie, dATP, dCTP, dGTP, dTTP, dUPT (in RNA instead of dTTP)