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Chapter 16 - Coggle Diagram
Chapter 16
DNA Repair/Chromosomes
Repair
proofreading
mismatch repair
excision repair
Mutations
changes in DNA
source of variation
Telomeres
ends of DNA
shorten over time
telomerase extends
Chromosome Structure
DNA + histones
nucleosome
Packing Levels
DNA - nucleosome - chromatin - chromosome
Chromatin Types
euchromatin (active)
heterochromatin (inactive)
Structure of DNA
Nucleotide
phosphate
sugar
base
Bases
A, T, G, C
Base pairing
A–T
hydrogen bonds
G–C
Chargaff rules
A = T
G = C
Double helix
2 strands
antiparallel
Genetic material
Griffin
transformation
bacteria change
Avery et al
DNA = transforming molecule
Hershey & Chase
phage injects DNA
protein stays outside
Conclusion
DNA = hereditary material
DNA replication
Prokaryotes vs Eukaryotes
Prokaryotes
1 origin
1 bubble
Eukaryotes
multiple origins
many bubbles
Strands
Leading strand
continuous
Lagging strand
discontinuous
Okazaki fragments
short segments
Enzymes
Topoisomerase
relieves tension
Helicase
breaks H-bonds
Single-strand binding proteins
stabilize DNA
Primase
RNA primer
DNA polymerase
DNA polymerase
5’ - 3’ only
DNA polymerase I
replaces primer
DNA ligase
joins fragments
Structure
origin of replication
replication fork
replication bubble
Direction Rules
5’ - 3’ synthesis
antiparallel strands