DNA Replication

WHAT IS DNA REPLICATION??

• Replication: copies itself exactly the same
• Any mistake in copying = mutation

What is DNA made of??

• One sugar base
• One phosphate base
• One nitrogen base (Adenine, Thymine, Cytosine and Guanine)
• A>>>T C>>>G

Process of DNA Replication

• Helicase "unzip" DNA molecule
• Enzymes breaks hydrogen bonds between bases

After it unwound.....

• SSB protein stabilize the unwound DNA
• prevent both strands from attaching

both strands?

• DNA splits to two parts: Leading strand and lagging strand
• Transcription: DNA copies itself to RNA

Leading strand

• Primase: generates short strands of RNA
• In leading strand synthesis DNA synthesis progresses in a 5'>>>3' direction
• it replicates continuously

Lagging strands

• replication is discontinuous
• DNA polymerase extends the primed segments, forming Okazaki fragments
• RNA replaces DNA
• DNA are joined together by DNA ligase

telomere

• noncoding DNA that contains repeat sequences and are called telomeres. As a result, a part of the telomere is removed in every cycle of DNA Replication.

one more thing.....

SCIENTISTS THAT CONTRIBUTES TO DNA REPLICATION

• Watson and Crick: discover the double helix structure
• Morgan: genea in chromosomes
• Mendel: inheritence in pea plants

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