Prokaryotes vs Eukaryotes. But first it’s QUIZ TIME!! Copier is down – deal with it 1.Write the...
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Transcript of Prokaryotes vs Eukaryotes. But first it’s QUIZ TIME!! Copier is down – deal with it 1.Write the...
Prokaryotes vsEukaryotes
But first it’s QUIZ TIME!!Copier is down – deal with it
1. Write the correct mRNA transcript based on the gene sequence below:
GTA GTA GGT
2. Use your codon chart to determine the sequence of amino acids dictated by the gene sequence above.
mRNA Amino Acid AGA arginine GGA glycine AGC serine GCA alanine CAG glutamine
3. Which mRNA would code for both amino acid sequences shown, simply by a shift in the reading frame?
…glutamine…glutamine…glutamine …serine… serine… serine
A. AGUAGUAGUAGU C. GCUGCUGCUGCUB. AGCAGCAGCAGC D. GCAAGCGCAAGC
Use the amino acid chart from question #3
…glycine…serine…glycine…
4. Which of the following DNA strands would code for the amino acid sequence shown above?
A. ACTCCTTCT C. CCGTCGACT
B. TCTCCGTCG D. CCTTCGCCT
#5 and #6
5. An incoming tRNA would attach to which site on the ribosome?
6. If the tRNA anticodon is UUU, what amino acid will it bring to the growing peptide chain?
#7 and #8
7. Spliceosomes cut out ______ and splice together ________ which get expressed.
8. Modifications to the ends of the mRNA transcript are required before leaving the nucleus. Which end (3’ or 5’) is modified with a Poly- A tail?
II. RNA modification
5’ cap chemically speaknig
The movie – yes there is a movie
• http://vcell.ndsu.nodak.edu/animations/mrnaprocessing/movie.htm
Why Cap and Poly- A tail?
• Protect the messenger!
• exonucleases – protect but destroy
• http://en.wikipedia.org/wiki/5'_cap
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 ever