Chapter 14 Flashcards
A-T G-C
Chargaffs rule
Nucleotides
Are the monomers that build DNA
A nucleotide is made up of 1,2,3
1 Penrose sugar, 2 phosphate group, 3 nitrogenous base
RNA ONLY
No T (thymine) only U (uracil)
RNA is for
Complementary base pairing
Nucleotides combine with each other via
Phosphodiester bonds
Directionality
Opposite direction
3-5
5-3
Chromatin
Interphase
When the phosphate bond holding the third phosphate to the nucleoside is broken the energy released is used to form the
Phosphodiester bonds
Between the incoming nucleotides of the growing chain
DNA pol I is an
Accessory protein important is DNA polymerization
DNA pol II is required for
DNA repair
DNA pol III is the enzyme necessary for
Adding new nucleotides on to the growing chain
Helicase is an
Enzyme that unwinds the DNA by breaking down the hydrogen bonds between the nitrogenous base pairs using ATP
DNA pol II can only add new nucleotides to the
3’ end
DNA pol I pieces them together later away from the replication fork this,
Form fragments called Okazaki fragments
The strand with Okazaki fragments is called the
Lagging strand
A protein called the sliding clamp holds the
DNA pol III in place
DNA polymerase III
Bacteria
Starts adding nucleotides to the 3’ -OH end of the primers
The gap between the two DNA fragments are sealed by DNA Ligase which helps in the formation of
Phosphodiester bonds
Strand elongation (adding new nucleotides to the two new strands) is done by
Pol a, pol b, and pol e, in eukaryotes
A sliding clamp protein called proliferating cell nuclear antigen (PCNA) holds the
DNA pol complex in place is eukaryotes
Point mutations
Affect a single base pair usually substitutions
Missense mutation
Result in the wrong amino acid being translated
Frame shift mutation
Result from insertions or deletions of nucleotides which shift the reading frame and the production of a nonfunctional protein
