Hydrogen bonds hold the structure together.Structure of DNAHuman DNA is organized into 46 separate chromosomes or (23 pairs)DNA wrapped around proteins, then coiled upIn between cell divisions, DNA is in a form called chromatin, which is loosely coiled and not visibleDuring cell divisions, DNA coils very tightly and becomes visibleChromosomes contain genesShort segment of DNA that contains the code, or recipe, for a proteinTranscription & Translation OverviewTranscriptionProcess of copying DNA of a gene into mRNA (messenger RNA)Occurs within the cellnucleusTranslationProcess of convertingthe mRNA template intoa proteinOccurs in the cytoplasm at ribosomesRNA StructureDNA & RNA are both nucleic acids made of nucleotides, but have different structures:DNADouble strandedSugar used is DeoxyriboseBasesG, A, C, and TFound only in the nucleusRNASingle strandedSugar used is RiboseBasesG, A, C, and UU can pair with ACan move from nucleus to cytoplasm3 Types of RNAMessenger RNA (mRNA)mRNA is a copy of the genetic information from DNA carried from nucleus to the ribosomes in the cytoplasm where protein synthesis occursRibosomal RNA (rRNA)Joins with proteins made in the cytoplasm to form the subunits of ribosomesTransfer RNA (tRNA)Transfers amino acids to the ribosomes where amino acids are joined to make polypeptidesTranscriptionA gene’s two strands of DNA separateOne DNA strand is copied to form an RNA molecule using complementary base pairingDNA mRNAC GG CT AA URNA Polymerase enzyme assists in making correct base pairingsMessenger RNA (mRNA) is formedEditing of mRNAMost human genes are made of sections called exons and intronsExons code for a protein (therefore must exit the nucleus to be Translated)Introns interrupt the coding portions of a geneDuring processing, introns are removed and exons are joined to form an edited mRNA moleculeEdited mRNA leaves the nucleus and enters the cytoplasmGenetic CodeThe genetic code is a triplet codeCodon:Sequence of three mRNA basesCodes for one amino acidThe Genetic Code is redundant64 different codons, but 20 different amino acidsSeveral different codons encode most amino acids, however each codon only codes for one amino acidA few codons have special meaning:Start CodonAUG (methionine amino acid): begins all genesCodes for both a start signal and an amino acidStop CodonsUAA, UAG, UGA: one ends each geneCode for only a stop signal, NOT an amino acidTranslation: Making a Protein from RNASeveral players involved in this process:Messenger RNA (mRNA): a copy of the DNA “recipe” (gene) containing codonsTransfer RNAs (tRNA): escort amino acids to the ribosome (site of translation); contain 3 bases called anticodons that are complementary to mRNA codonsRibosomes: serve as a docking station to bring together mRNA and incoming tRNA (with its amino acid)Amino Acids: form the subunits of the protein being manufactured1. InitiationRibosome subunits attach to mRNA at start codon (AUG)First tRNA (carrying methionine) comes in by pairing of its anticodon (UAC) to the start codon (AUG)2. ElongationtRNAs bring in specific amino acids, in the correct orderRibosome moves down one codon at a timeEach amino acid is joined by a peptide bond to the chain, and released from its tRNAEmpty tRNAs leave the ribosome3. TerminationStop codon causes termination of the processRibosome falls off the mRNA and releases the protein chainProtein folds into its three dimensional shapeTranslationTranslation proceeds very quicklyE. coli (a bacterium) can polymerize 40 amino acids per secondA second ribosome can begin translation before the first ribosome is doneIn fact, many ribosomes can simultaneously translate a single mRNABIOL 1140 1st Edition Lecture 7Outline of Last Lecture I. Glycolysisa. Glucose, moleculesII. Citric acid cella. Pyruvate, acetylIII. Respirationa. Cell, anaerobicOutline of Current Lecture I. Transcription, translationa. Process, convertingII. RNA, DNAa. 3 types of DNA III. Genetic Codea. Making a protein Current Lecture  Hydrogen bonds hold the structure together.  Structure of DNA- Human DNA is organized into 46 separate chromosomes or (23 pairs)- DNA wrapped around proteins, then coiled up - In between cell divisions, DNA is in a form called chromatin, which is loosely coiled and not visible- During cell divisions, DNA coils very tightly and becomes visible- Chromosomes contain genes o Short segment of DNA that contains the code, or recipe, for a proteinThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Transcription & Translation Overview Transcription- Process of copying DNA of a gene into mRNA (messenger RNA)- Occurs within the cell - nucleus Translation- Process of converting - the mRNA template into- a protein- Occurs in the cytoplasm at ribosomes RNA Structure DNA & RNA are both nucleic acids made of nucleotides, but have different structures:  DNA Double stranded Sugar used is Deoxyribose Bases G, A, C, and T Found only in the nucleus RNA Single stranded Sugar used is Ribose Bases G, A, C, and U U can pair with A Can move from nucleus to cytoplasm3 Types of RNA- Messenger RNA (mRNA)o mRNA is a copy of the genetic information from DNA carried from nucleus to the ribosomes in the cytoplasm where protein synthesis occurs- Ribosomal RNA (rRNA)o Joins with proteins made in the cytoplasm to form the subunits of ribosomes- Transfer RNA (tRNA)o Transfers amino acids to the ribosomes where amino acids are joined to make polypeptidesTranscription- A gene’s two strands of DNA separate- One DNA strand is copied to form an RNA molecule using complementary base pairingDNA mRNA C G G C T A A U- RNA Polymerase enzyme assists in making correct base pairings- Messenger RNA (mRNA) is formed Editing of mRNA- Most human genes are made of sections called exons and intronso Exons code for a protein (therefore must exit the nucleus to be Translated)o Introns interrupt the coding portions of a gene During processing, introns are removed and exons are joined to form an edited mRNA molecule- Edited mRNA leaves the nucleus and enters the cytoplasmGenetic Code- The genetic code is a triplet code- Codon:- Sequence of three mRNA bases- Codes for one amino acid- The Genetic Code is redundant- 64 different codons, but 20