DNA Flashcards
what is DNA and main role
hereditary material in humans and almost all other
organisms and long-term storage of
information.
[tells the cell how to build an organism]
Structure of DNA
long thin molecule made up of nucleotides
In the shape of a Double Helix
Nucleotides
There are four different types of
nucleotides: adenine, thymine, cytosine,
and guanine.
[the nucleotides are referred to as “bases”]
Together, a base, sugar, and phosphate are
called a nucleotide.
Backbone
Holding the nucleotides together is a backbone made of phosphate and deoxyribose. [side of the lade]
purines and pyrimidines
Two of the bases are called purines: adenine and guanine and the pyrimidines are called: thymine and cytosine
A–>T
C—>G
Bases
DNA bases pair up with each other, A with
T and C with G, to form units called base
pairs. Each base is also attached to a sugar
molecule and a phosphate molecule.
Together, a base, sugar, and phosphate are
called a nucleotide.
Purines
Structure: Double carbon-nitrogen ring with four nitrogen atoms
Size: Bigger
Source: Adenine and Guanine in both
DNA and RNA
Prymidines
Structure: Single carbon-nitrogen ring with two nitrogen atoms
Size: Smaller
Source: Cytosine in both DNA and RNA, Uracil only in RNA, Thymine only in DNA
Location Of DNA for different Organism
- nucleus [human, plants ]
- mitochondria [human, plants]
- cytoplasm [bacteria]
- chloroplast [plants]
DNA Discoveries
Fred Griffith (1928) - Experiments with pneumonia and baceterial transformation determined that there is a molecule that controls inheritance
Hershey-Chase Bacteriophage Experiment (1952) - discovered that DNA from viruses can program bacteria make new viruses.
Organization
DNA + histones(proteins) = chromatin
Condensed chromatin – chromosome
Total chromosome set - genome
