DNA Flashcards
What does DNA stand for?
Deoxyribonucleic acid
What’s the monomer in DNA
Nucleotide
What’s the structure of a DNA nucleotide ?
-deoxyribose
-a phosphate group
-an organic nitrogen containing base
What bond joins nucleotides together
Phosphodiester bond
What forms the backbone of a polynucleotide strand?
Sugar and phosphate
What are the 4 bases in DNA?
-adenine
-cytosine
-thymine
-guanine
What are the complementary base pairs in DNA?
A-T
G-C
What bond joins completely bases together?
Hydrogen
What’s the function of DNA?
It contains genes that code of polypeptides.
What’s the structure of DNA and why is it important
It’s helical. This makes it compact and protects the bases. It’s double stranded so each strand can act as a template
What were the 3 originally proposes methods of DNA replication
- conservative replication
-semi conservative replication
-dispersive replication
Describe semi conservative replication
- DNA helicase unwinds the double helix and breaks the hydrogen bonds
-Each strand acts as a template.
-individual nucleotides align with their complementary base pair and bond with hydrogen bonding
-adjacent nucleotides bond by DNA polymerase with phosphdiester bonds.
Why is it called semi conservative replication
One strand in the new DNA is full conserved from the original
Who did the experiment used as evidence for semi conservative replication
Meselson and Stahl
Describe Meselson and Stahls experiment
-cells of bacteria were grown on N15 isotope
-cells were allowed to divide on this heavy nitrogen
-bacteria was moved to medium of N14
-samples were taken after every division and spun in a centrifuge
