DNA Replication

DNA replication

• What does it mean?

– DNA is copied

• One double helix

become two double

helicies

Why do our cells need to copy their

DNA?

• Anytime your body makes more cells, those

new cells need their own DNA

– Growth and repair

– Reproduction

How can a cell copy its DNA?

• Things to consider?

– It has to be EXACTLY the same

• How do cells do anything?

– They get proteins to do the work

• Enzymes!

Watch a video!

• Bozeman Science DNA Replication

– https://youtu.be/FBmO_rmXxIw?list=PL7A750281

106CD067

– From 5:00 to 8:20

– Summarize on your paper

– http://www.hhmi.org/biointeractive/dna-

replication-advanced-detail

So, now what?

• What do we need to know about this whole mess?

• In general, what needs to happen?

– DNA needs to be unwound

– New nucleotides need to be added to exposed bases

– Replication moves in opposite directions

• Results?

– 2 strands each with ½ old and ½ new

Unwinding• Helicase breaks the hydrogen bonds which

causes the two strands to separate

Base Pairing• DNA Polymerase adds nucleotides on each of

the 2 strands

– Moves in opposite directions on each strand

– It proofreads also (Only 1 in 1 billion errors)

Results

• Two double helices are formed,

each one using ½ of the original

parent strand

– Semiconservative replication

• http://highered.mcgraw-

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