DNA Functions & Replication

Function of DNA

STORE genetic info. to build proteins; passed to offspring

COPY to provide instructions to new cells when cells divide

EXPRESS instructions to make proteins (protein synthesis)

WHEN does DNA Replicate?

when cells get too large & divide

WHERE does DNA Replicate?

in the nucleus (eukaryotes)

in the cytoplasm (prokaryotes)

WHY does DNA Replicate?

so each new replicated cell has the exact same DNA as its “parent” cell

PRODUCT of DNA Replication

2 perfect identical copies of DNA

Topoisomerase

unwinds DNA double helix

Helicase

breaks hydrogen bonds holding nucleotides together and separates two parent strands (creates a replication fork)

Parent Strand

original DNA strand that serves as a template

Replication Fork

site/area where two parent strands separate

Single Strand Binding Proteins (SSB)

bonds to single strand DNA to prevent two strands from bonding back together

Replication happens in what direction?

5’ to 3’

(leading strand and lagging strand created)

Leading Strand

replicated continuously toward the replication fork

DNA Primase

adds short strands of RNA primer

RNA Primer

signals DNA polymerase to start adding new nucleotide bases

DNA Polymerase

enzyme that adds complementary nucleotides to create new strand of DNA (RNA primers are released)

Lagging Strand

CANNOT be replicated continuously!! must be synthesized in short strands called Okazaki Fragments