![Notes 11-25-09
Page 190
The connection between Genes and Proteins
-The study of metabolic defects provided evidence that genes
specify proteins
-Genes => tell cells how to build proteins
-Beadle and Tatum Experiment
-One gene – One polypeptide
Beadle and Tatum Experiment
(Metabolic pathways
-Worked with fungus pathways
-Final phase [d], grows from a.
-As long as DNA sequences are correct, all enzymes do the right thing.
-However, if gene is mutated and enzyme one does not work
-A enzyme damaged, B can still transform into C and then D
and work properly
-A, B, C damaged, no-go, D directly would still work.
-One gene affects particular enzyme, as gene makes
enzyme.
-One gene, one enzyme hypothesis
-“One gene, one polypeptide/protein”.
-Gene simply instructs how to build protein](https://image.slidesharecdn.com/11-25-09notes-091203084041-phpapp02/85/11-25-09-Notes-1-320.jpg)
![Bacterial Protein Synthesis
-Make small copy of segment of DNA describing how to make
small segment of protein
-mRNA – messenger RNA – copy of gene
-RNA – uracil instead of thymine
-Complimentary base pairing system used. mRNA is like 2nd DNA
strand.
-Translate DNA/RNA to protein sequence
Eukaryotic Protein Synthesis
-Transcription
-RNA processing
-Translation
-link up outside nuclear pore with ribsomes, ribosomes read code
-in the genetic code nucleotide triplets, RNA [codons] speicy amino
acid sequence
-codons tell which amino acid to place next in the polypeptide chain.
-UUU = phenylalanine -UAA = leucine
-page 192 – genetic code chart
-AUG – Start codon – Methianine
-STOP codons – UAA, UGA, UAG
-First and last letter important, third not so much.
-“Synonyms”
Transcription – Initiation
-RNA polymerase
-nucleotides can only be added to the three prime end of the RNA chain,
just like DNA
-Sides pulled apart, temp strand read.
-3 prime end toward 5 prime end read
Transcription – Elongation
-Complimentary base pairing, attaching to 3 prime end
-Adenine -> uracil
-Cytosine -> guanine
-Thymine -> adenine
-Guanine -> cytosine
Transcription – Termination
-Stop codon
Eukaryotic cells modify RNA after transcription
-Introns => unusable information that needs to be cut out
-reattaches important part of RNA](https://image.slidesharecdn.com/11-25-09notes-091203084041-phpapp02/85/11-25-09-Notes-2-320.jpg)
11 25 09 Notes
- 1. Notes 11-25-09 Page 190 The connection between Genes and Proteins -The study of metabolic defects provided evidence that genes specify proteins -Genes => tell cells how to build proteins -Beadle and Tatum Experiment -One gene – One polypeptide Beadle and Tatum Experiment (Metabolic pathways -Worked with fungus pathways -Final phase [d], grows from a. -As long as DNA sequences are correct, all enzymes do the right thing. -However, if gene is mutated and enzyme one does not work -A enzyme damaged, B can still transform into C and then D and work properly -A, B, C damaged, no-go, D directly would still work. -One gene affects particular enzyme, as gene makes enzyme. -One gene, one enzyme hypothesis -“One gene, one polypeptide/protein”. -Gene simply instructs how to build protein
- 2. Bacterial Protein Synthesis -Make small copy of segment of DNA describing how to make small segment of protein -mRNA – messenger RNA – copy of gene -RNA – uracil instead of thymine -Complimentary base pairing system used. mRNA is like 2nd DNA strand. -Translate DNA/RNA to protein sequence Eukaryotic Protein Synthesis -Transcription -RNA processing -Translation -link up outside nuclear pore with ribsomes, ribosomes read code -in the genetic code nucleotide triplets, RNA [codons] speicy amino acid sequence -codons tell which amino acid to place next in the polypeptide chain. -UUU = phenylalanine -UAA = leucine -page 192 – genetic code chart -AUG – Start codon – Methianine -STOP codons – UAA, UGA, UAG -First and last letter important, third not so much. -“Synonyms” Transcription – Initiation -RNA polymerase -nucleotides can only be added to the three prime end of the RNA chain, just like DNA -Sides pulled apart, temp strand read. -3 prime end toward 5 prime end read Transcription – Elongation -Complimentary base pairing, attaching to 3 prime end -Adenine -> uracil -Cytosine -> guanine -Thymine -> adenine -Guanine -> cytosine Transcription – Termination -Stop codon Eukaryotic cells modify RNA after transcription -Introns => unusable information that needs to be cut out -reattaches important part of RNA
- 3. -spliceosomes => part enzyme, part RNA perform this job.