Remember…DNA replication…
• Replication – makes an exact copy of
the genetic material for all new cells
Semiconservative Model (part old/part new)
Bellwork: Draw the graph and answer
the question
• The graph shows the rate of
activity for the enzyme catalase
at different temperatures.
Catalase helps convert hydrogen
peroxide to oxygen and water.
The rate of catalase activity is
directly related to the percent
increase in oxygen.
• Based on the graph, what
conclusions can be made about
the functioning of catalase?
Science Fact of the Day:
An Octopus has three hearts.
From DNA to Protein
Write 2 questions you have from the
video as you watch. 
Central Dogma
DNA
mRNA
Only dealing with
this part today!
Protein
Transcription
1) DNA has instructions for the
rest of the cell
2) DNA gets transferred into
mRNA (messenger RNA)
3) mRNA leaves nucleus,
crosses cytoplasm, and
attaches to a ribosome
Transcription Preview
DNA & RNA Differences:
1) RNA has ribose
instead of deoxyribose
2) RNA is single
stranded
3) RNA has uracil
instead of thymine
RNA
Add this to your notes!!
DNA to DNA
DNA to RNA
CG
GC
TA
AT
CG
GC
TA
AU
DNA/RNA match
up!!!!
What’s the point?
Gene expression: genetic information is turned
into a useful product, one section at a time
Think of it like this:
DNA = master blueprints, recipe book
mRNA = partial instructions (you don’t need
blueprints for the whole house to put in the
foundation), one recipe
Big Ideas
• first step in making a protein
(polypeptide)
• occurs in the nucleus
• DNA makes mRNA
–mRNA is sent out of the nucleus
–one gene (a small section of the DNA
strand) that codes for one protein at a
time
Practice Replication and Transcription
• We’re going to make a “Protein Synthesis Tri-fold”
• Follow my directions, step by step 
• Use your understanding of Transcription to
complete the worksheet you picked up at the
beginning of class. It’s due tomorrow.