The flow of information
 Knowledge
 Unit
 Encode
 Transmission
 Perception
The flow of genetic information
The flow of genetic information
Chapter 6
Replication, Maintenance,
and Rearrangements of Genomic DNA
Chapter 7
RNA Synthesis and Processing
Chapter 8
Protein Synthesis, Processing, and Regulation
Chapter 6
Replication & Maintenance
The flow of genetic information
Replication
1. The transmission of genetic information
2. From parent to offspring
3. Reproduction & heredity
Maintenance
1. The conservation of genetic information
2. From DNA damage
3. DNA repair system
Let’s watch how they work
http://www.hhmi.org/biointeractive/dna-replication-advanced-detail
DNA Replication
The double helix structure facilitates
the accurate transmission of hereditary
information
DNA Replication
Because of the base pairing rules,
the sequence of one strand determines
the sequence of the partner strand.
The two strands can be separated and
complementary sequences synthesized
to generate two identical daughter
strands.
Because the two daughter helices have
one parent strand and one newly
synthesized strand, the replication
process is called semiconservative
replication.
Why are DNA molecule the two strands (double helix)?
Structure comparison in the stability
Why are DNA molecule the two strands (double helix)?
Structure comparison in the stability
Why are DNA molecule the two strands (double helix)?
Structure comparison in the function
Genetic information
Why is DNA replicated in the semiconservative way?
Economy & Efficiency
Why are the two strands of a DNA molecule antiparallel?
Strctural aspect
Parallel strands
Antiparallel strands
DNA Replication
Formation of phospho diester bond
in which a bond formed between the
3' -OH group and the 5' phosphate group
through condensation reaction
Based on a template
DNA Replication
The reaction requires four activated precursor units:
deoxynucleoside 5’-triphosphates (dNTPs)-dATP, dGTP, dCTP, dTTP
DNA Polymerase
DNA polymerase catalyzes 1] template-directed 2] phosphodiester-linkage formation
DNA Polymerase
DNA polymerase synthesizes DNA only in the 5’ to 3’ direction:
adding a dNTP to the 3’ hydroxyl group of a growing chain.
Fidelity of DNA replication
Faithful copying, accuracy of DNA replication, is essential the preservation of information:
DNA polymerase’s essential capacity
Fidelity of DNA replication
Base complementarity:
Energetically stable and favorable interaction
Thermodynamic aspect
Structural aspect
Fidelity of DNA polymerase
Shape complementarity:
DNA polymerase's structure for determination of fidelity for purine & pyrimidine
Compatible nucleotide