http://www.pbs.org/wgbh/nova/teachers/interactives/regulating-genes/index.html

http://www.sumanasinc.com/webcontent/animations/content/lacoperon.html

http://www.teachertube.com/viewVideo.php?title=Lac_operon&video_id=217174

Warmup

• What are the 4 levels of protein structure?• What are 2 reasons why proteins are

important?• Factor 8 is a blood clotting protein that most

hemophiliacs lack. How would you make and purify large quantities of factor 8?

Do you have the same DNA in all of your cells?

Yes! All cells from an organism has the same DNA.

How is it possible that we have different types of cells? (What makes these cells

different?)

What makes these cells different?

Proteins make cells look different. In different types of cells, some proteins are made and other proteins are not made, changing their phenotype.

Hint: DNA RNA  Transcription

 Translation Protei

n

What makes these cells different?

 Transcription

 Translation Protei

nRNA

Phenotype

(Gene)

Genotype

Gene On Protein/Phenotype

Gene Off

DNA

No Protein

How do cells control what protein is made and what protein is not made?

Cells control the process gene expression (how proteins are made from DNA ) by gene regulation (how some genes get turned on and other genes get turned off).

ProteinGene Regulator

Gene regulation allows for cell differentiation (when cells only express certain proteins to help them perform a specific function).

Interactive: http://www.pbs.org/wgbh/nova/teachers/interactives/regulating-genes/index.html

The lac operon regulates genes by turning on the genes to digest lactose only when there is lactose around it.

lac operon animation

Lac operon video 2

Gene regulation in Prokaryotes

An operon is a link of genes that code for proteins that perform a similar function

General diagram of lac operon

Diagram of lac operon when lactose is NOT present

Diagram of lac operon when lactose IS present

Gene Regulation in Eukaryotes

Gene regulation in eukaryotes is complex! It can occur at different steps along the gene expression process.

Regulation of DNA PackingWhen DNA is tightly wrapped in chromatin,

RNA polymerase cannot bind to transcribe the gene.

Ex: X chromosome inactivation

Oswald and Sisters!

Initiation of TranscriptionSimilar to how prokaryotes regulate transcription.

- Has regulator genes that code for activator proteins (Turn on) and repressor proteins (Turn off) to bind operator

- Usually one promoter and operator for each gene. (few operons)- Uses transcription factors to help RNA polymerase transcribe

RNA Processing and Breakdown

Alternative splicing is when different exons are cut to form the mRNA making different proteins from the same gene

Regulation of Translation

mRNA gets degraded before it is translated to a protein

Protein Alteration and Breakdown

Proteins can be cut or degraded

Why Regulate Genes?