1 / 13

Molecular Basis for Relationship between Genotype and Phenotype

Molecular Basis for Relationship between Genotype and Phenotype. genotype. DNA. DNA sequence. transcription. RNA. translation. amino acid sequence. protein. function. phenotype. organism. Protein Synthesis: Brief Summary 3 Stages Initiation Elongation Termination

spendleton
Download Presentation

Molecular Basis for Relationship between Genotype and Phenotype

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Molecular Basis for Relationship between Genotype and Phenotype genotype DNA DNA sequence transcription RNA translation amino acid sequence protein function phenotype organism

  2. Protein Synthesis: Brief Summary • 3 Stages • Initiation • Elongation • Termination • Catalytic Proteins • Initiation Factors • Elongation Factors • Termination Factors • Hydrolysis of GTP provides energy to drive some reactions. • mRNA, rRNA, and tRNA are involved.

  3. Protein Synthesis: Initiation in Prokaryotes Refer to Figure 9-13 from Introduction to Genetic Analysis, Griffiths etal., 2015. Shine-Dalgarno sequence pairs with 16S rRNA of 30S subunit. IF3 keeps 30S subunit dissociated from 50S subunit. Formyl group is added to methionine when associated with the initiator tRNA. IF1 and IF2 allows only initiator tRNA to enter P site. Initiation factors are released when two ribosomal subunits associate. Refer to Figure 9-14, Griffiths etal., 2015.

  4. Protein Synthesis: Initiation in Eukaryotes eIF4A, eIF4B, and eIF4G associates with 5’ end, then with 40S subunit and initiator tRNA. mRNA is unwound by movement of this complex in 5’ -> 3’ direction. 60S subunit associates with initiation complex when start codon is recognized. Initiation factors are released when the two ribosomal subunits associate. Refer to Figure 9-15 from Introduction to Genetic Analysis, Griffiths etal., 2015.

  5. Important Features of Ribosome Refer to Figure 9-12 from Introduction to Genetic Analysis, Griffiths etal., 2015. A - aminoacyl site P - peptidyl site E - exit site

  6. Proteins and RNA Molecules Compose the Two Subunits of a Ribosome Refer to Figure 9-10 from Introduction to Genetic Analysis, Griffiths etal., 2015.

  7. Protein Synthesis: Elongation EF-Tu associates with aminoacyl-tRNA to form a ternary complex. Correct match of ternary complex with codon in A site (decoding center) changes conformation of ribosome. EF-Tu leaves ternary complex, and peptide bond is formed between amino acids as amino acids are positioned together in peptidyltransferase center. Refer to Figure 9-16 from Introduction to Genetic Analysis, Griffiths etal., 2015. Amino acid in P site is transferred to amino acid in A site. Translocation requires GTP and EF-G. EF-G enters A site, shifting tRNAs. When EF-G leaves, A site is open for a new ternary complex. A new ternary complex associates with A site, and deacylated tRNA leaves from E site.

  8. Protein Synthesis: Termination tRNA molecules do not recognize stop codons. Termination codons are recognized by release factors. (RF1, RF2, RF3 in bacteria) UAA and UAG are recognized by RF1. UAA and UGA are recognized by RF2. RF3 assists in release activity. Release factors bind to a stop codon in the A site by association between codon and tripeptide of RF. Polypeptide is released from P site when RF fits into A site. Release of polypeptide is followed by dissociation of ribosomal subunits. Refer to Figure 9-17 from Introduction to Genetic Analysis, Griffiths etal., 2015.

  9. Universality of Genetic Information Transfer: Genetic code is essentially identical for all organisms. There are exceptions. UGA STOP TRP TRP System “universal” mammalian mitochondria yeast mitochondria AUA ILE MET ILE

  10. Comparison of Gene Expression Prokaryotes One type of RNA polymerase synthesizes all RNA molecules. mRNA is translated during transcription. Genes are not split. They are continguous segments of DNA. mRNAs are often polycistronic. Eukaryotes Three different types of RNA polymerases synthesize different classes of RNA. mRNA is processed before translation. Genes are often split. They are not continguous segments of coding sequences. mRNAs are mostly monocistronic.

  11. Molecular Basis for Relationship between Genotype and Phenotype genotype DNA DNA sequence transcription RNA translation amino acid sequence protein function phenotype organism

  12. Molecular Basis for Relationship between Genotype and Phenotype genotype DNA DNA sequence transcription RNA translation amino acid sequence protein function phenotype organism

  13. All Protein Interactions in an Organism Compose the Interactome Proteome: Complete set of proteins produced by genetic material of an organism. Interactome: Complete set of protein interactions in an organism. Refer to Figure 9-21 from Introduction to Genetic Analysis, Griffiths etal., 2015.

More Related