DNA

1. DNA Replication

2. DNA Replication • Process by which DNA makes a copy of itself • The copy must be exactly like the original

3. Steps in DNA Replication • The DNA “unzips” as the weak chemical bonds holding the bases together are broken • The parent strand (the original strand) acts as a template (something from which a copy can be made) • The enzyme DNA polymerase attaches free-floating nucleotides in the nucleus to the parent strand to create the daughter strand

4. Steps in DNA Replication (cont.) • Once the nucleotides have been brought in, the backbone forms • The DNA polymerase also proofreads the new strands to make sure there are no mistakes in the copy

5. Semi-conservative • DNA replication is said to be semi-conservative, meaning that each new copy of DNA has one original strand (parent strand) and one new strand (daughter strand)

6. Example • Give the complementary sequence for the following strand of DNA: A T T C G A C T G A • If this piece of DNA was to replicate, what would the resulting strands of DNA look like? T A A G C T G A C T

7. Example (cont.) A T T C G A C T G A  parent strand T A A G C T G A C T  daughter strand A T T C G A C T G A  daughter strand T A A G C T G A C T  parent strand