2 10-1 From Genes to protein Objectives Compare the structure of DNA and RNASummarize the process of transcriptionOutline the major steps of translationSCS:B-4.4
3 Proteins are made by decoding the information in DNA Traits are determined by proteins that are built according to the instructions found on DNAProteins are not built directly from DNA but from RNA (ribonucleic acid)Copy of the DNA that is decoded
4 RNA – the facts Single stranded string of nucleotides Different bases Has uracil instead of thymineDifferent sugar – ribose
6 Gene expression – protein synthesis A gene’s instructions for making a protein are coded in the sequence of nucleotides in the geneInstructions are transferred from DNA to RNA in a process called transcriptionThe instructions are then decoded to make a protein in a process called translation
7 TranscriptionTakes place in the nucleus of eukaryotic organisms and in the cytoplasm of prokaryotic organisms
8 Steps of transcription RNA polymerase binds to the DNA molecule at the specific sequence that needs to be translatedRNA polymerase unwinds and separates strandsRNA polymerase adds nucleotides and links complimentary base until it reaches a “stop” signal.RNA detaches then it leaves the nucleus to be translated.
10 Genetic code is written in 3 nucleotide “words” 3 types of RNA are made during transcriptionMessenger RNA (mRNA) – copy of the DNATransfer RNA (tRNA) – carries nucleotides to the ribosomeRibosomal RNA (rRNA) – part of the ribosome
12 Each codon codes for an amino acid or a start or stop signal RNA instructions are written as a series of 3 nucleotide sequences of mRNA called codonsEach codon codes for an amino acid or a start or stop signalthe sequence can be decoded using the a genetic codeSpecifies the amino acid, so it tells you what protein is being madeNearly universal
14 Translation Takes place in the cytoplasm mRNA, tRNA, and rRNA are involvedRibosomes are the site of protein synthesisTranslation can take place at multiple places on the mRNA
15 Steps of translationmRNA leaves the nucleus; ribosome attaches at the start codon (AUG)tRNA brings the complimentary anticodon with a amino acid attachedA peptide bond forms after another tRNA brings a second amino acidThe ribosome continues the above process until a stop message is reached in the mRNA.The newly made protein detaches and the ribosome break apart.
17 10-2 Gene regulation and Structure ObjectivesSummarize how protein synthesis is regulatedDescribe the types of mutations that can occur during translationSCS:B-4.4
18 Protein synthesis is controlled by “on” and “off” switches This switch is called an operatorControls the access of RNA polymerase to the sequence of DNAA protein (repressor) binds to the DNA to keep RNA polymerase from binding to the promoter site (the group of genes that codes for a specific protein)
19 Regulation is more complex in eukaryotic organisms Regulated in many ways
20 Most of your DNA does not code for anything useful Introns – non coding regionAre “cut” out during translationExons – regions that actually code for proteins
21 Mutations result in nonfunctional proteins Types of point mutations (occur in only a few nucleotides)SubstitutionInsertionDeletion
22 Mutations can result in no protein being made, a nonfunctional protein, or have no affect at all Many genetic disorders are a result of a single nucleotide mutation