DNA Synthesis

1
DNA Synthesis

• Chapters 16 17

2
Nucleotide structure

• 3 components
• 1. 5 carbon sugar (ribose)
• 2. Phosphate
• 3. Nitrogenous base

3
Dehydration synthesis

• 5 to 3
• Phosphate (5C) binds with the hydroxyl group
  (3C)
• Removes water
• Phosphodiester bond
• Bond links 2 sugars of nucleotides

4
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5
Double Helix

• Two strands held together
• A forms 2 hydrogen bonds with T
• G forms 3 hydrogen bonds with C

6
Duplication

• Semiconservative replication
• Old strand template
• DNA has one old one new strand

7
Duplication

• Leading side
• Continuous strand in the 5 to 3 direction
• Lagging strand
• Side that is duplicated in short segments
• Okazaki fragments
• Short stretches on the lagging side

8
Duplication

• DNA Polymerases
• Lengthens by adding new nucleotides
• DNA primase
• Forms primer to start replication

9
Duplication

• DNA helicase
• Opens helix in front of the polymerase
• DNA gyrase
• Releases strain on the molecule
• DNA ligase
• Bonds Okazaki fragments

10
Duplication

• Replication fork
• Site of opening of the DNA
• Site of active replication

11
Stages of replication

• Initiation
• Elongation
• Termination

12
Protein synthesis

• DNA RNA protein
• Transcription Translation

13
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14
RNA

• rRNA ribosomal RNA
• Site where polypeptides are assembled
• tRNA transfer RNA (anti-codon)
• Transport aa for building polypeptides
• mRNA messenger RNA (codon)
• Transcribes the information
• Directs which aa are assembled

15
Ribosomes
16
Transcription

• Nucleus
• Initiation
• Promoter
• RNA polymerase
• Elongation
• Termination
• Stop signal (hair pin)

17
Transcription
18
Translation

• Cytoplasm in eukaryotes
• 1. Initiation
• 2. Elongation
• 3. Termination

19
Translation
20
Translation
21
Eukaryotes
22
Protein synthesis