 Watson & Crick  Beedle & Tatum

 Processes:  Transcription (DNA to mRNA)  Translation (mRNA to protein)  Importance of location  Eukaryotes  Prokaryotes

 Review  Types of RNA in Gene Expression  mRNA (messenger)-provides code for protein  tRNA (transfer)-carries amino acids  rRNA (ribosomal)-directs translation

 Requires DNA-dependent RNA Polymerase ▪ Core enzyme + sigma factor = holoenzyme  Three forms in Eukaryotic Nuclei ▪ RNA Pol I –Pre-rRNA ▪ RNA Pol II**--Pre-mRNA ▪ RNA pol III –Pre-tRNA

 RNA recognizes region to be transcribed  Promotor regions ▪ TATA box ▪ CAAT box

 Complementary mRNA produced from DNA

 Often zones with high GC levels  Loop and release of mRNA  Protection  5’ capped with 7-methyl G  3’ tail polyadenylation

 Prokaryotic cells translate immediately into protein  Eukaryotic cells process mRNA before translation occurs  Cutting out Introns  Protecting transcript

 Splicing occurs by sequence  snRNA and snRNP (spliceosomes), and/or ribozymes (self-splicing enzymes)  Many different proteins can result from one transcript

 mRNA  Transcript  tRNA  Carrier for amino acids  Ribosomes  Two sub-units of protein with three pieces of RNA

 Codons- 3 nucleotide codes for amino acids  20 amino acides  64 codons  3 stop codons (UGA, UAA, UAG)  1 Start codon (AUG-methionine)  Each codon brings in a tRNA anti-codon that contributes one amino acid to the protein

 Small sub-unit of ribosome binds to mRNA  Methionine “start”  Large sub-unit of ribosome enters  Initiation factors involved

 Connection  Next tRNA enters  1 st tRNA “hands” amino acid to 2 nd tRNA, then leaves  Ribosome slides to free the next space  Continuation for length of protein  Elongation factors involved

 Stop Codon is reached  RF’s bind to stop codon  Protein is released  Ribosomal units disassociate

 Exploring factors influencing gene expression  Expression and repression of genes

 Brooker, R. J. (2011). Concepts of Genetics + Connect Plus Access Card. McGraw-Hill Science Engineering, New York, NY.  Brooker, R. J., (2012). Genetics: analysis and principles. 4th Ed. McGraw- Hill Higher Education, New York, NY.  King, M. D. (2013). The Medical Biochemistry Page. Retrieved from:  McClean, P. E. (2013). Transcription. Retrieved from: m m  Unknown (2013). Three types of RNA polymerase in eukaryotic nuclei. Retrieved from: 7.euk_trxn_apparatus.pdfhttp://mcb.berkeley.edu/courses/mcb110/ZHOU/lec.5- 7.euk_trxn_apparatus.pdf

 Cap & Tail ding jpg ding jpg  RNA Elongation on_diagram1.png on_diagram1.png  RNA Initiation  Processing )_Image.gif )_Image.gif  Translation Initiation  Translation Elongation  Translation Termination nsla.jpg nsla.jpg