From DNA to Protein Genotype to Phenotype
Information from Genes to Proteins RNA (ribonucleic acid) Key mediator between DNA & polypeptide Only one strand Sugar: ribose Nitrogenous bases Adenine, guanine, cytosine, and uracil
Information from Genes to Proteins Central dogma DNA codes for the production of RNA, RNA codes for the production of proteins (polypeptide) Protein does not code for the production of protein, RNA, or DNA RNA viruses are the exceptions
Transcription Components of transcription DNA template Only one strand is used Ribonucleoside triphosphates to act as substrates RNA polymerase enzyme Messenger RNA (mRNA) is produced Transfer RNA (tRNA) is synthesized Ribosomal RNA (rRNA) is synthesized
Transcription Initiation Elongation Termination Finish product – mRNA Requires a promoter Tells RNA polymerase where to start, which strand to transcribe, and the direction Elongation RNA polymerase unwinds the DNA (~10 base pairs at a time) Reads in the 3’ to 5’ direction Termination Specific DNA sequences tells RNA polymerase to stop adding nucleotides Finish product – mRNA
Transcription
Transcription http://bcs.whfreeman.com/thelifewire/content/chp12/1202001.html
Translation mRNA translated into Proteins tRNA must read mRNA codons correctly tRNA must deliver the amino acids that correspond to the mRNA codons it has read tRNA It carries an amino acid It associates with mRNA molecules It interacts with ribosomes
Translation Ribosome is the workbench Two subunits (large & small) Eukaryotes have 3 different molecules of ribosomal RNA (rRNA)
Ribosome A site (amino acid) P site (polypeptide E site (exit) Where the tRNA anticodon binds to the mRNA codon P site (polypeptide Where the tRNA adds its amino acid E site (exit) Where the tRNA resides before being released
Translation Initiation Elongation Termination Initiation complex-starts translation Start codon (AUG) Codes 3’ to 5’ Elongation Anticodon of tRNA bind to the codon at the A site Amino acids become linked at the P site Free tRNA moves to E site & is released, ribosome shifts by one codon & the process repeats Termination Stop codon (UAA, UAG, or UGA) enter A site hydrolysis occurs in the bonds between the polypeptide chain, tRNA, & P site
Translation Initiation Small ribosomal subunit binds to the recognition sequence on mRNA Methionine-charged tRNA binds to the AUG “start” codon, completing the initiation complex The large ribosomal subunit joins the initiation complex with the tRNA now occupying the P site
Translation Elongation
Transcription Termination
Genetic Code
http://www.biostudio.com/demo_freeman_protein_synthesis.htm
Mutations Somatic mutations Germ line mutations Point mutations Body cells Passes on to the daughter cells after mitosis Germ line mutations Cells that give rise to gametes Passes on to a new organism at fertilization Point mutations Single base pairs on a single gene One allele becomes another allele Chromosomal mutations Change the position of a DNA segment without actually removing the genetic information May cause DNA to be irretrievably lost or duplicated
Mutations Four Types of Chromosomal mutations Explain the four types and the end result Discuss spontaneous or induced mutations, with examples Explain the relationship between mutations and evolution 2-3 pages, single space, 12pt font, Times New Roman