Molecular Genetics
Are we controlled by our DNA?
Refer to pg 119-150 in Holtzclaw,
Ch 16-21 in Campbell
Last year...

What do you remember of DNA
Replication and Protein Synthesis?
DNA
genetic info
>
mRNA
message
>
protein
action molecule
So What?

Making the big connections...
◦ How many cells do you have?
◦ Compare the DNA in each of your cells
◦ Compare the protein products in each of your
cells...

How does your body
KNOW when to make
some proteins and not
others?
◦ THIS is gene expression
So What?

Model Organism: The Fruit Fly
So What?

More flies!
◦ - Using Gene expression to study eye
development
What do you think?
Are you controlled by your DNA?
What are the implications of studying
Gene expression?
1) Free Write (3 min)
 2) Learning Walk (5 min)
 3) No Hands Discussion (5 min)

Review last year…

Learning Intentions!
Gene Expression
You must know:

The functions of the three parts of an operon

The role of repressor genes in operons

The impact of DNA methylation and
histone acetylation on gene expression

The role of gene regulation in embryonic
development and cancer.
Gene Expression
Rather important, don’t you think?:

The functions of the three parts of an operon

The role of repressor genes in operons

The impact of DNA methylation and
histone acetylation on gene expression

The role of gene regulation in embryonic
development and cancer.
The Operon – p. 131 in Holtz.

What is it?
◦ Unit of genetic function
◦ Found in bacteria/phages/some eukaryotes
◦ Consists of:
 Promotor – site of RNA polymerase binding
 Operator – controls access of RNA polymerase
within the promotor
 Genes of the Operon –regulated together by the
operon
Regulatory Genes

What do they do?
◦ Produce repressor proteins that bind to the
operator of an operon to block RNA
polymerase from transcribing

Repressible Operon
◦ Usually “on,” can be inhibited...

Inducible Operon
◦ Usually “off,” can be induced...
The Try Operon – Repressible
The Lac Operon – Inducible
Let’s make sure we get this…