Lecture 10 Flashcards
What is Chargaffs theory
significant DNA variation between species- could be genetic material
composition of DNA varies between species
What is Chargaffs Rule
[A]=[T] and [G]=[C]
What is the basic DNA Structure
a double-stranded helical (helix) molecule with particular features
bases are perpendicular to the length of the DNA molecule
what are the Base Rules
One ring bases (C, T) join with the two ring base (A, G).
sugar (pentile) + Phosphate group + base. 5’ prime carbon attaches to phosphate
What is a polynucleotide
Nucleotide monomers joined with the Phosphodiester Bonds/linkage (covalent) to form a polynucleotide= (nucleic acid)
where to Nucleotides join
the OH group on the 3rd carbon reacts with the phosphate group on 5th carbon on another nucleotide
What direction are DNA and RNA always synthesised
DNA and RNA are always synthesised in the 5’ to 3’ direction
How is the double helix formed
Two strands are in antiparallel (3-5 and 5-3)
hydrogen bonds between base pairs
How Many hydrogen bonds does A-T have
Two Hydrogen Bonds
How many hydrogen bonds does G-C have
Three Hydrogen Bonds
what is the Watson/Crick model
a double-stranded helix sugar phosphate backbone-outside bases-inside hydrogen bonds stablise polynucleotide strands orientated in the opposite direction
what is the Semi-conservative model of replication
Each DNA strand of the double helix is used as a template strand for the synthesis of two new strands
Why does DNA replicate
to make more cells, growth, injury and pregnancy
