Prokaryotes vsEukaryotes

II. RNA modification

5” cap chemically speaknig

The movie – yes there is a movie

• http://vcell.ndsu.nodak.edu/animations/mrnaprocessing/movie.htm

III Bacteria genetics

• Binary fission

Prokaryotic variation in genetic make-up

• Mutations

• Genetic recombination– Transformation– Transduction– Conjugation

Transformation

Transduction

Conjugation

IV. Control of metabolic pathways

A. Two ways1. Vary the activity of the enzymes (inhibit

them or promote their ability) – feedback inhibition pathways

2. Vary the # of enzymes present – regulate enzyme production at the gene expression level

B. Gene regulation in bacteria

• OPERONS!– Need to know that an operon is a section of

DNA that contains genes for a protein– Need to know the parts and players

Ex 1 – Lac Operon

Ex 2 Tryptophan operon

A closer look at the parts

• A) promoter – site on DNA where RNA polymerase can bind and begin transcription

• B) operator – the “on/off” switch, located between promoter and structural genes

• C) structural genes – genes that code for a protein

Important players

• Repressor – a protein that when active will bind to the operator thus blocking transcription

• Regulatory gene – the DNA sequence that codes for the repressor protein

• Co-repressor – a molecule that attaches to an inactive repressor and makes it active

• Inducer – a molecule that attaches to an active repressor and makes it inactive

How they work together

• Negative regulation

• Positive regulation

Negative regulation

• Two examples– Lac operon– Tryptophan operon – best animation link