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DNA Replication. How does DNA copy itself when a new cell needs to be made?. DNA Replication replicate means “to copy” replicación del ADN replicar medios "para copiar“ DNA Replication nhân rộng các phương tiện "để sao chép". 3’. Parental DNA Molecule. 5’. Replication Fork. 3’. 5’. - PowerPoint PPT Presentation
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DNA ReplicationDNA Replication
How does DNA copy itself when a new cell needs to be made?
DNA Replication
replicate means “to copy”
replicación del ADN
replicar medios "para copiar“
DNA Replication
nhân rộng các phương tiện "để sao chép"
DNA Replication la replicación la replicación del ANDdel AND sao chép DNAsao chép DNA
Replication Forks: hundreds of Y-shapedregions of replicating DNA molecules where new strands are growing. Horquillas de replicación: cientos de Y-forma regiones de la replicación de las moléculas de ADN donde las nuevas hebras están creciendo.Forks Replication: hàng trăm Y-hình khu vực tái tạo các phân tử DNA nơi sợi mới đang phát triển.
ReplicationReplicationForkFork
Parental DNA MoleculeParental DNA Molecule
3’
5’
3’
5’
Replication Bubbles:
a. Hundreds of replicating bubbles (Eukaryotes).
b. Single replication fork (bacteria).
Burbujas de replicación:
a. Cientos de burbujas de replicación (eucariotas).
b. Tenedor de replicación Individual (bacterias).
Replication Bubbles:
a. Hàng trăm bong bóng sao chép (Eukaryote).
b. Độc thân nhân rộng ngã ba (vi khuẩn).
Bubbles Bubbles
Strand Separation:
1. Helicase: enzyme which catalyze the unwinding and separation (breaking H-Bonds) of the parental double helix.
2. Single-Strand Binding Proteins: proteins which attach and help keep the separated strands apart.
Separación Strand:
1. Helicase: enzima que catalizan el desenrollado y la separación (romper H- Bonds) de la doble hélice parental.
2. Single-Strand Binding Proteínas: las proteínas que se unen y ayudan a mantener las hebras separadas aparte.
Tách Strand:
1. helicase: enzyme xúc tác cho sự thư giãn và tách (chia H- trái phiếu) của cha mẹ xoắn kép.
2. Single-Strand Binding Protein: protein đính kèm và giúp giữ các sợi tách ra ngoài.
Strand Separation:
3. Topoisomerase: enzyme which relieves stress on the DNA molecule by allowing free rotation around a single strand.
Enzyme
DNA
Enzyme
Priming:1. RNA primers: before new DNA strands
can form, there must be small pre-existing primers (RNA) present to start the addition of new nucleotides (DNA Polymerase).
2. Primase: enzyme that polymerizes (synthesizes) the RNA Primer.
Synthesis of the new DNA Strands:
1. DNA Polymerase: with a RNA primer in place, DNA Polymerase (enzyme) catalyze the synthesis of a new DNA strand in the 5’ to 3’ direction.
RNARNAPrimerPrimerDNA PolymeraseDNA Polymerase
NucleotideNucleotide
5’
5’ 3’
2. Leading Strand: synthesized as a single polymer in the 5’ to 3’
direction.
RNARNAPrimerPrimerDNA PolymeraseDNA PolymeraseNucleotidesNucleotides
3’5’
5’
3. Lagging Strand: also synthesized in the 5’ to 3’ direction, but
discontinuously against overall direction of replication.
RNA PrimerRNA Primer
Leading StrandLeading Strand
DNA PolymeraseDNA Polymerase
5’
5’
3’
3’
Lagging StrandLagging Strand
5’
5’
3’
3’
4. Okazaki Fragments: series of short segments on the lagging strand.
Lagging Strand
RNARNAPrimerPrimer
DNADNAPolymerasePolymerase
3’
3’
5’
5’
Okazaki FragmentOkazaki Fragment
5. DNA ligase: a linking enzyme that catalyzes the formation of a
covalent bond from the 3’ to 5’ end of joining stands.
Example: joining two Okazaki fragments together.
Lagging Strand
Okazaki Fragment 2Okazaki Fragment 2
DNA ligaseDNA ligase
Okazaki Fragment 1Okazaki Fragment 1
5’
5’
3’
3’
Question:
• What would be the complementary DNA strand for the following DNA sequence?
DNA 5’-GCGTATG-3’DNA 5’-GCGTATG-3’
Answer:Answer:
DNA 5’-GCGTATG-3’DNA 5’-GCGTATG-3’
DNA 3’-CGCATAC-5’DNA 3’-CGCATAC-5’
