Post on 20-Sep-2019
transcript
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-
hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535
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