SECTION IDENTIFYING DNA AS THE GENETIC
Fisher 2015SECTION8.1IDENTIFYING DNA AS THE GENETIC MATERIALStudy GuideKEY CONCEPTDNA was identified as the genetic material through a seriesof experiments.VOCABULARYbacteriophageMAIN IDEA: Griffith finds a “transforming principle.”Write the results of Griffith’s experiments in the boxes below.Experiments1. Injected mice withR bacteria2. Injected mice withS bacteria4. Mixed killed S bacteria with Rbacteria and injected theminto micemice livedmice diedmice livedmice diedFound live Sbacteria in themice’s bloodCHAPTER 8From DNA to ProteinsCopyright McDougal Littell/Houghton Mifflin Company.3. Killed S bacteria and injectedthem into miceResults5. Which type of bacteria caused disease, the S form or the R form?S Form6. What conclusions did Griffith make based on his experimental results?Griffith concluded that some material must have been transferred from the heat- killedS-bacteria to the live R-bacteria.Unit 3 Resource BookMcDougal Littell BiologyTransforming PrincipleStudy Guide61
STUDY GUIDE, CONTINUEDMAIN IDEA:Avery identifies DNA as the transforming principle.7. Avery and his team isolated Griffith’s transforming principle and performed three teststo learn if it was DNA or protein. In the table below, summarize Avery’s work by writingthe question he was asking or the results of his experiment.Avery’s QuestionResultsWhat type of molecule does the transformingprinciple contain?Showed DNA was present NOTproteinDo the proportions in the extract matchthe proportions found in DNA?Which type of enzyme destroys the ability ofthe transforming principle to function?Hershey and Chase confirm that DNA is the genetic material.8. Proteins containsulfurphosphorusCHAPTER 8From DNA to ProteinsAn enzyme which destroys DNA9. DNA containsbut very little.phosphorusbut nosulfur.10. Summarize the two experiments performed by Hershey and Chase by completing thetable below. Identify what type of radioactive label was used in the bacteriophage andwhether radioactivity was found in the bacteria.ExperimentBacteriophageBacteriaExperiment 1 infected w/ radioactive sulfur atoms in proteinExperiment 2 infected w/ radioactive phos DNANo radioactivity foundFound radioactivity in thebacteria!Vocabulary Check11. Explain what a bacteriophage is and describe or sketch its structure.Copyright McDougal Littell/Houghton Mifflin Company.MAIN IDEA:The ratio of nitrogen to phosphorus in thetransforming principle is similar to the ratiofound in DNA.Better known as a "phage"-takes over bacterium's genetic machinery and directs it to makemore viruses.62Study GuideUnit 3 Resource BookMcDougal Littell Biology
SECTION8.1IDENTIFYING DNA AS THE GENETIC MATERIALPower NotesGriffith’s experiments:Refer to pg 61 of Study GuideREPEAT Don't' do .Conclusion:Avery’s experiments:Refer to page 62 of Study Guide Conclusion:CHAPTER 8From DNA to ProteinsCopyright McDougal Littell/Houghton Mifflin Company.Hershey and Chase’s experiments: Refer to page 62 of Study Guide Conclusion:Unit 3 Resource BookMcDougal Littell BiologyPower Notes63
SECTION8.1IDENTIFYING DNA AS THE GENETIC MATERIALReinforcementKEY CONCEPT DNA was identified as the genetic material through a series ofexperiments.A series of experiments helped scientists recognize that DNA is the genetic material.One of the earliest was done by Frederick Griffith who was studying two forms of thebacterium that causes pneumonia. The S form was surrounded by a coating that madethem look smooth. The R form did not have a coating, and the colonies looked rough.Griffith injected these bacteria into mice and found that only the S type killed the mice.When the S bacteria were killed, they did not cause the mice to die. However, whenkilled S bacteria were mixed with live R bacteria, the mice died and Griffith found liveS bacteria in their blood. This led Griffith to conclude that there was a transformingprinciple that could change R bacteria into S bacteria.Oswald Avery, another scientist, developed a way to purify this transforming principle.He then conducted a series of chemical tests to find out what it was. Many scientiststhought that DNA was too simple of a molecule to be the genetic material and thatproteins, being more complex, were a better candidate. However, Avery made three keydiscoveries about his samples of transforming principle that showed otherwise: DNA was present, not protein. The chemical composition matched that of DNA, not protein. The addition of enzymes that break down DNA made the transforming principleAlfred Hershey and Martha Chase carried out the final, conclusive experiments in 1952.Bacteriophages are viruses that infect bacteria and take over bacteria’s genetic machineryto make more viruses. They consist of a protein coat surrounding DNA. Hershey andChase grew these viruses in cultures containing radioactively labeled sulfur, a componentof proteins, or phosphorus, a component of DNA. Bacteria were then infected withviruses that either had radioactively labeled sulfur or phosphorous. Hershey and Chasenext separated the viruses from the bacteria with a blender. The bacteria had radioactivephosphorus but no radioactive sulfur. Hershey and Chase concluded that the viruses’DNA, but not the protein coat, had entered the bacteria.1. What was “transformed” in Griffith’s experiment?R bacteria into S bacteria2. Which molecule had entered the bacterium in the Hershey-Chase experiments, sulfur orphosphorus? Which molecule is a major component of DNA?The viruses DNA entered the bacterium because the only radioactive material youcould see was phosphorus! Phosphorus is a major component of DNA.64ReinforcementUnit 3 Resource BookMcDougal Littell BiologyCopyright McDougal Littell/Houghton Mifflin Company.CHAPTER 8From DNA to Proteinsinactive. The addition of enzymes that break down proteins or RNA had no effect.
SECTION8.2STRUCTURE OF DNAStudy GuideKEY CONCEPTDNA structure is the same in all organisms.VOCABULARYnucleotidebase pairing rulesdouble helixMAIN IDEA: DNA is composed of four types of nucleotides.In the space below, draw a nucleotide and label its three parts using words and arrows.phosphate group-sugar-nitrogen baseCHAPTER 8From DNA to ProteinsCopyright McDougal Littell/Houghton Mifflin Company.page 230 in textbook1. How many types of nucleotides are present in DNA?Four types:Thymine, Adenine, Cytosine, & Guanine2. Which parts are the same in all nucleotides? Which part is different?Same: phosphate group & sugar (deoxyribose) Different: their Nitrogen containing basesMAIN IDEA: Watson and Crick developed an accurate model of DNA’sthree-dimensional structure.3. What did Franklin’s data reveal about the structure of DNA?DNA was a helix4. How did Watson and Crick determine the three-dimensional shape of DNA?Watson and Crick were shown Franklin's photograph by her partner Wilkin's. Lookingat Franklin's X-ray photo's gave them the hint they needed.Unit 3 Resource BookMcDougal Littell BiologyStudy Guide65
STUDY GUIDE, CONTINUED5. How does DNA base pairing result in a molecule that has a uniform width?Watson & Crick paired double ringed nucleotides with single-ringed nucleotides, created samewidth and fit like a puzzle piece!MAIN IDEA:Nucleotides always pair in the same way.6. What nucleotide pairs with T? with C?C attaches to GsingledoubleT attaches to AsingledoubleIn the space below, draw a DNA double helix. Label the sugar-phosphate backbone, thenitrogen-containing bases, and the hydrogen bonds.Vocabulary Check7. Explain how the DNA double helix is similar to a spiral staircase.Two strands of DNA wind around each other like a twisted ladder.8. How do the base pairing rules relate to Chargaff ’s rules?Chargaff said the amount of A in an organism equaled the amount of T in an organismand the amount of G in an organism equaled the amount of C in an organism. ThisCopyright McDougal Littell/Houghton Mifflin Company.CHAPTER 8From DNA to ProteinsOpen textbook to page 233. Copy figure 8.7would be do to the fact that for every A there is a T and for every G there is a C becausethey are paired together.66Study GuideUnit 3 Resource BookMcDougal Littell Biology
SECTIONSTRUCTURE OF DNA8.2Power NotesOverall shape:Parts of aDNA moleculeDouble HelixNitrogencontaining basessingle ringBackbonedouble ringPyrimidinesPurinesthymineadenine1.phosphate group2.sugar (deoxyribose)cytosineguanineCHAPTER 8From DNA to ProteinsCopyright McDougal Littell/Houghton Mifflin Company.Base pairing rules:T always pairs with AC always pairs with GT Hbond ABonding1.2.GCATHydrogen BondsCovalent BondsCChargaff’s rules:Amount ofA Tcovalent bondGC GUnit 3 Resource BookMcDougal Littell BiologyPower Notes67
SECTION8.2STRUCTURE OF DNAReinforcementKEY CONCEPT DNA structure is the same in all organisms.DNA is a chain of nucleotides. In DNA, each nucleotide is made of a phosphate group,a sugar called deoxyribose, and one of four nitrogen-containing bases. These four basesare cytosine (C), thymine (T), adenine (A), and guanine (G). Two of the bases, C and T,have a single-ring structure. The other two bases, A and G, have a double-ring structure.Although scientists had a good understanding of the chemical structure of DNA by the1950s, they did not understand its three-dimensional structure. The contributions ofseveral scientists helped lead to this important discovery. Erwin Chargaff analyzed the DNA from many different organisms and realized thatthe amount of A is equal to the amount of T, and the amount of C is equal to theamount of G. This A T and C G relationship became known as Chargaff ’s rules. Rosalind Franklin and Maurice Wilkins studied DNA structure using x-rayJames Watson and Francis Crick applied Franklin’s and Chargaff’s data in building athree-dimensional model of DNA. They confirmed that DNA is a double helix inwhich two strands of DNA wind around each other like a twisted ladder. The sugar andphosphate molecules form the outside strands of the helix, and the bases pair together inthe middle, forming hydrogen bonds that hold the two sides of the helix together. Abase with a double ring pairs with a base with a single ring. Thus, in accordance withChargaff’s rules, they realized that A pairs with T, and C pairs with G. The bases alwayspair this way, which is called the base pairing rules.1. What did Chargaff’s rules state?The amount of A T and the amount of C G in an organism2. What did Franklin’s data show about the three-dimensional structure of DNA?That DNA is a helix consisting of two strands that are a regular, consistent widthapart.3. What forms the backbone strands of the DNA double helix? What connects thesestrands in the middle?Copyright McDougal Littell/Houghton Mifflin Company.CHAPTER 8From DNA to Proteinscrystallography. Franklin’s data suggested that DNA is a helix consisting of twostrands that are a regular, consistent width apart.Sugar and phosphate molecules form the outside strand of the DNA helix. In the middle are thebase pairs. Hydrogen bonds between the base pairs; (ex C to G) connect the two sides together.68ReinforcementUnit 3 Resource BookMcDougal Littell Biology
SECTION8.3DNA REPLICATIONStudy GuideKEY CONCEPTDNA replication copies the genetic information of a cell.MAIN IDEA:VOCABULARYreplicationDNA polymeraseReplication copies the genetic information.1. What is DNA replication?The process in which DNA is copied during the cell cycle.2. Where does DNA replication take place in a eukaryotic cell?In the nucleus.3. When is DNA replicated during the cell cycle?DNA is replicated during the S (synthesis) stage.4. Why does DNA replication need to occur?Assures that every cell in an organism has a complete set of identical genetic information.5. What is a template?Template- a pattern to follow- InstructionsCHAPTER 8From DNA to Proteins6. If one strand of DNA had the sequence TAGGTAC, what would be the sequence ofthe complementary DNA strand?Copyright McDougal Littell/Houghton Mifflin Company.ATCCATGMAIN IDEA:Proteins carry out the process of replication.7. What roles do proteins play in DNA replication?Proteins- hold the strands of DNA apart while they serve as a template.8. What must be broken for the DNA strand to separate?Hydrogen bonds between the nucleotides. Hydrogen bonds that are connecting the basepairs are broken.9. Why is DNA replication called semiconservative?Because you have 2 identical DNA molecules that result from the process. But each newmolecule has one strand from the original molecule. So, conserved some energy in themaking process.Unit 3 Resource BookMcDougal Littell BiologyStudy Guide69
STUDY GUIDE, CONTINUEDUse words and diagrams to summarize the steps of replication, in order, in the boxes below.10.11.12.-Free floating nucleotidespair up w/ exposed baseson each template-DNA polymerase bondsthese nucleotides- DNA molecule unzips-nucleotide base pairsseparate-Two identical doublestranded DNA moleculesresult-Replication beginspg. 237MAIN IDEA:pg. 237pg 237Replication is fast and accurate.13. Human chromosomes have hundreds oforigins, where the DNA isunzipped so replication can begin.14. DNA polymerase has aproofreaderfunction that enables it to detect errorsVocabulary Check15. Explain what DNA polymerase is by breaking the word into its parts.DNA polymer- means makes DNA polymersBonds the new nucleotide to the template.ase-means enzyme16. Write a short analogy to explain what replication is.NABe Creative17. People sometimes like to display bumper stickers that relate to their trade or field ofstudy. For example, a chemist may have a bumper sticker that says “It takes alkynes tomake the world.” Then, chemists or other people who know that an alkyne is a moleculethat contains carbon atoms joined by a triple bond get a nice little chuckle out of theplay on words. Use your knowledge of DNA replication to write a bumper sticker.NA70Study GuideUnit 3 Resource BookMcDougal Littell BiologyCopyright McDougal Littell/Houghton Mifflin Company.CHAPTER 8From DNA to Proteinsand correct them.
SECTIONDNA REPLICATION8.3Power NotesGeneral description:ReplicationIdentify thestructures.Process1.1.UnzipsBackbone phosphate group& sugar(deoxyribose) old strandof DNA molecule2.Free FloatingNucleotidespair up w/exposed baseson templateCopyright McDougal Littell/Houghton Mifflin Company.DNAbond thesepolymerasenucleotides togetherto form new strandsBase pairs3.DNApolymerase4.End resultNucleotideCHAPTER 8From DNA to Proteins3.2.New strand of DNAmolecule4. TwoidenticaldoublestrandedDNA molecule resultUnit 3 Resource BookMcDougal Littell BiologyPower Notes71
SECTION8.3DNA REPLICATIONReinforcementKEY CONCEPT DNA replication copies the genetic information of a cell.Every cell needs its own complete set of DNA, and the discovery of thethree-dimensional structure of DNA immediately suggested a mechanism by which thecopying of DNA, or DNA replication, could occur. Because the DNA bases pair inonly one way, both strands of DNA act as templates that direct the production of a new,complementary strand. DNA replication takes place during the S stage of the cell cycle.The process of DNA replication is very similar in both eukaryotes and prokaryotes,but we will focus on eukaryotes. During the S stage of the cell cycle, the DNA is loosely organized in the nucleus.Certain enzymes start to unzip the double helix at places called origins ofreplication. The double helix unzips in both directions along the strand. Eukaryoticchromosomes are very long, so they have many origins of replication to help speedthe process. Other proteins hold the two strands apart. The unzipping exposes the bases on the DNA strands and enables free-floatingnucleotides to pair up with their complementary bases. DNA polymerases bondthe nucleotides together to form new strands that are complementary to the originaltemplate strands. The result is two identical strands of DNA. DNA replication is described asDNA polymerase not only bonds nucleotides together. It also has a proofreadingfunction. It can detect incorrectly paired nucleotides, clip them out, and replace themwith the correct nucleotides. Uncorrected errors are limited to about one per 1 billionnucleotides.1. Why is DNA replication described as semiconservative?Copyright McDougal Littell/Houghton Mifflin Company.CHAPTER 8From DNA to Proteinssemiconservative because each DNA molecule has one new strand and one originalstrand.DNA replication is described as semiconservative because each DNA molecule hasone new strand and one original strand.2. What are two major functions that DNA polymerase performs?1. Bonds nucleotides together2. Proofreading function72ReinforcementUnit 3 Resource BookMcDougal Littell Biology
SECTIONTRANSCRIPTION8.4Study GuideKEY CONCEPTTranscription converts a gene into asingle-stranded RNA molecule.VOCABULARYcentral dogmamessenger RNA (mRNA)RNAribosomal RNA (rRNA)transcriptiontransfer RNA (tRNA)RNA polymeraseMAIN IDEA: RNA carries DNA’s instructions.Label each of the processes represented by the arrows in the diagram below. Write whereeach of these processes takes place in a eukaryotic cell in parentheses.Replication (takes place in the 3.(takes place in the nucleus)(Takes place in cytoplasm)Copyright McDougal Littell/Houghton Mifflin Company.DNARNA4. Contains the sugar deoxyribose5.Has the bases A, C, G, and UACGT6. Typically double-strandedMAIN IDEA:Contains the sugar ribose (has extraoxygen)CHAPTER 8From DNA to ProteinsFill in the table below to contrast DNA and RNA.RNA is a single strand ofnucleotides)Transcription makes three types of RNA.7. What enzyme helps a cell to make a strand of RNA?RNA polymerasesUnit 3 Resource BookMcDougal Littell BiologyStudy Guide73
STUDY GUIDE, CONTINUED8. Summarize the three key steps of transcription.1. RNA enzyme recognizes the start site of gene9.2. RNA polymerase uses 1 strand of DNA as a template, & strings together compstrand of RNA3. Once the entire gene has been transcribed, the RNA strand detaches completelyfromtheDNA.Writebasic function of each type of RNA in the chart below.Type of RNACarries instructions that is translated to forma proteinForms Ribosomes- a cells protein factoriesTransfers/brings amino acids from cytoplasma ribosome to help make the growing proteinmRNArRNAtRNAMAIN IDEA:FunctionThe transcription process is similar to replication.Both processes occur within the nucleus of eukaryotic cells. Both are catalyzed(sped up) by enzymes. Both involve unwinding of DNA double helix.11. List two ways that the end results of transcription and replication differ.The job of replication is to ensure that each new cell will have 1 complete set ofgenetic instructions. Replication occurs only once during each round of the cellcycle. InCheckcontrast,a cell may need 100's of copies of certain proteins. Many RNAVocabularycantypebeoftranscribedmolecules12. Howdoes the name of eachRNA tell what fromit does?a single gene at the same time to helpproduce more protein.m messengerCopyright McDougal Littell/Houghton Mifflin Company.CHAPTER 8From DNA to Proteins10. List two ways that the processes of transcription and replication are similar.r ribosomalt transfer13. What is transcription?The proces of copying a sequence orf DNA to produce a complementary strand ofRNA74Study GuideUnit 3 Resource BookMcDougal Littell Biology
SECTION8.4TRANSCRIPTIONPower NotesCentral Dogma1. DNA2.3.RNA4.DNA: sugar deoxyriboseATCG basesRNA: sugar Double strand of nucleotides 5.ProteinriboseAUCGSingle strand of NucleotidesTranscriptionLabel the parts on the lines below. Summarize the steps of transcription in the boxes.1.2.start siteDNA TemplateCopyright McDougal Littell/Houghton Mifflin Company.Transcription complex6. RNA3.5.RNA Strand4.RNA Type1. MessengerRNA (mRNA)2.3.rRNAtRNAUnit 3 Resource BookMcDougal Littell BiologypolymerasenucleotidesCHAPTER 8From DNA to Proteins7.DNA templateFunctioncarries genetic information/instructionsRibosomal RNATransfer RNA transfers/brings amino acids to helpmake growing proteinPower Notes75
SECTION8.4TRANSCRIPTIONReinforcementKEY CONCEPT Transcription converts a gene into a single-stranded RNA molecule.DNA provides the instructions needed by a cell to make proteins. But the instructionsare not made directly into proteins. First, a DNA message is converted into RNA in aprocess called transcription. Then, the RNA message is converted into proteins in aprocess called translation. The relationship between these molecules and processes issummed up in the central dogma, which states that information flows in one direction,from DNA to RNA to proteins.During transcription, a gene is transferred into RNA. Specific DNA sequences and acombination of accessory proteins help RNA polymerase recognize the start of a gene.RNA polymerase is a large enzyme that bonds nucleotides together to make RNA.RNA polymerase, in combination with the other proteins, forms a large transcriptioncomplex that unwinds a segment of the DNA molecule. Using only one strand of DNAas a template, RNA polymerase strings together a complementary RNA strand that hasU in place of T. The DNA strand zips back together as the transcription complex movesforward along the gene.Transcription makes three main types of RNA. Messenger RNA (mRNA) is the intermediate message between DNA and proteins.It is the only type of RNA that will be translated to form a protein. Ribosomal RNA (rRNA) forms a significant part of ribosomes. Transfer RNA (tRNA) carries amino acids from the cytoplasm to the ribosomeduring translation.The DNA of a cell therefore has genes that code for proteins, as well as genes that codefor rRNA and tRNA.1. What is stated in the central dogma?That information flows in one direction DNA to RNA to proteins2. What are the three main types of RNA? Which is translated into a protein?mRNA, rRNA, tRNA76ReinforcementmRNA is translated into proteinUnit 3 Resource BookMcDougal Littell BiologyCopyright McDougal Littell/Houghton Mifflin Company.CHAPTER 8From DNA to ProteinsLike DNA, RNA is a nucleic acid. It is made of nucleotides that consist of a phosphategroup, a sugar, and a nitrogen-containing base. However, RNA differs in important waysfrom DNA: (1) RNA contains the sugar ribose, not deoxyribose; (2) RNA is made up ofthe nucleotides A, C, G, and uracil, U, which forms base pairs with A; (3) RNA is usuallysingle-stranded. This single-stranded structure enables RNA to fold back on itself intospecific structures that can catalyze reactions, much like an enzyme.
SECTIONTRANSLATION8.5Study GuideKEY CONCEPTTranslation converts an mRNA messageinto a polypeptide, or protein.MAIN IDEA:VOCABULARYtranslationcodonstop codonstart codonanticodonAmino acids are coded by mRNA base sequences.1. What is translation?2.The process that converts, or translates, an mRNA message into a polypeptideprotein.What is a codon?A three-nucleotide sequence that codes for an amino acid3. Would the codons in Figure 8.13 be found in a strand of DNA or RNA?RNA why? U4. What is a reading frame?Codons read in right order, without spaces, and no overlaps. A change in thereading frame changes the resulting protein.Refer to Figure 8.13 to complete the table below.Amino Acid or FunctionCopyright McDougal Littell/Houghton Mifflin Company.5. AGAarginine (Arg)6. UAG7.STOPtryptophan (Trp)UGG8. GGAMAIN IDEA:9.CHAPTER 8From DNA to ProteinsCodonglycine (Gly)Amino acids are linked to become a protein.RibosomesandtRNAare the tools that help a cell translatean mRNA message into a polypeptide.10. Thesmall11. ThelargeUnit 3 Resource BookMcDougal Littell Biologysubunit of a ribosome holds onto the mRNA strand.subunit of a ribosome has binding sites for tRNA.Study Guide77
STUDY GUIDE, CONTINUED12. A tRNA molecule is attached to anamino acidanticodonat one end and has anat the other end.Fill in the cycle diagram below to outline the steps of translation.Ribosome assembles onstart codon of mRNA strand.Initiation: small subunit ribosome w/ tRNA andamino acid attaches to mRNA at the start codon.Protein synthesis is initiated.Termination: When the ribosomeB. Elongation: A new tRNA and aminoacid encounters the ribosome andone of three stop codons.links at the next codon. ProcedureThe ribosome releases fromrepeats.mRNAthe small subunit can nowbe loaded with newtRNA and startWhen the ribosome encountersa stop codon, it falls apart andtranslation again.the protein is released.Vocabulary Check13. What are AGG, GCA, and GUU examples of?amino acids14. What is a set of three nucleotides on a tRNA molecule that is complementary to anmRNA codon?15.Anticodon- a set of three nucleotides that is complementary to an mRNA codon ex:anticodon CCC pairs w mRNA codon GGGWhat do codons code for in addition to amino acids?Codons code for nucleotides- sequence ex: AUG78Copyright McDougal Littell/Houghton Mifflin Company.CHAPTER 8From DNA to ProteinsC.A.Study GuideUnit 3 Resource BookMcDougal Littell Biology
SECTIONTRANSLATION8.5Power NotesReading frame:3 codons read in aseriesnucleotides strung togetherto code for aminoacidsCodon3 nucleotidesequence thatcodes foran amino acidStart codon:methionineStop codon:signal the end of aminoacid chainAnticodonRibosome small subunit Common language:Triplet Codea set of 3nucleotides thatis complementaryto an mRNA codonlarge subunitTranslation1.Partsstart codon2. peptide bondCopyright McDougal Littell/Houghton Mifflin Company.3.tRNAActs like an adaptorbetween mRNA and amino acids.On one end tRNA carries freefloating amino acids and on theother end it carries anticodons toProcesscomp. a codonon a mRNAInitiationstrand.CHAPTER 8From DNA to Proteins4.1.Transfer RNA (tRNA)large ribosomeCysMetLeu2.Elongationanticodon8.mRNA6. small ribosomeReading Frame7.5.Unit 3 Resource BookMcDougal Littell Biology3.TerminationPower Notes79
SECTION8.5TRANSLATIONReinforcementKEY CONCEPT Translation converts an mRNA message into a polypeptide, orprotein.Translation is the process that converts an mRNA message into a polypeptide, or protein.An mRNA message is made up of combinations of four nucleotides, whereas proteinsare made up of twenty types of amino acids. The mRNA message is read as a series ofnon-overlapping codons, a sequence of three nucleotides that code for an amino acid.Many amino acids are coded for by more than one codon. In general, codons that codefor the same amino acid share the same first two nucleotides. Three codons, called stopcodons, signal the end of the polypeptide. There is also a start codon, which both signalsthe start of translation and codes for the amino acid methionine. This genetic code is thesame in almost all organisms, so it is sometimes called the universal genetic code.At the start of translation, a small subunit binds to an mRNA strand. Then the largesubunit joins. A tRNA molecule binds to the start codon. Another tRNA molecule bindsto the next codon. The ribosome forms a bond between the two amino acids carried by thetRNA molecules and pulls the mRNA strand by the length of one codon. This causes thefirst tRNA molecule to be released and opens up a new codon for binding. This processcontinues to be repeated until a stop codon is reached and the ribosome falls apart.1. What is a codon?A sequence of 3 nucleotides that code for an amino acid.2. What role does tRNA play in translation?Copyright McDougal Littell/Houghton Mifflin Company.CHAPTER 8From DNA to ProteinsAlthough tRNA and rRNA are not translated into proteins, they play key roles in helpingcells translate mRNA into proteins. Each tRNA molecule folds up into a characteristicL shape. One end has three nucleotides called an anticodon, which recognize and bindto a codon on the mRNA strand. The other end of the tRNA molecule carries a specificamino acid. A combination of rRNA and proteins make up the ribosome. Ribosomesconsist of a large and small subunit. The large subunit has binding sites for tRNA. Thesmall subunit binds to the mRNA strand.Transfers/brings amino acids from cytoplasm to a ribosome to help make growingprotein.3. What forms the bond between neighboring amino acids?The ribosome80ReinforcementUnit 3 Resource BookMcDougal Littell Biology
SECTION8.6GENE EXPRESSION AND REGULATIONStudy GuideKEY CONCEPTGene expression is carefully regulated in both prokaryoticand eukaryotic cells.MAIN IDEA:VOCABULARYpromoteroperonexonintronProkaryotic cells turn genes on and off by controlling transcription.1. Why is gene expression regulated in prokaryotic cells?Allows bacteria to better respond to stimuli and to conserve energy2. In prokaryotic cells, gene expression is typically regulated at the start oftranscriptionpromotor3. A.is a segment of DNA that helps RNA polymerase recognizethe start of a gene.4. Anoperonis a region of DNA that includes aoperatorpromotor, anstructural genethat code for proteins, and one or moreneeded to carry out a task.Copyright McDougal Littell/Houghton Mifflin Company.mediumwithout lactoseaddedThe repressorcontinues tobind to theoperator.5.7.8.Bacteriagrowingin culturemediumwith lactoseaddedUnit 3 Resource BookMcDougal Littell Biologylactosebinds to therepressor.Repressorfalls off esRNApolymerasetranscribesthe genesin the lacoperon.CHAPTER 8From DNA to ProteinsComplete the cause-and-effect diagram below about the lac operon.6.BlocksTranscription repressorproteinThe resultingtranscript istranslatedinto 3 enzymes.9.NAStudy Guide81
STUDY GUIDE, CONTINUEDMAIN IDEA:Eukaryotic cells regulate gene expression at many points.10. Why do the cells in your body differ from each other?Cells differ from each other because differerent sets of genes are expressed indifferent types of cells.11. What role do transcription factors play in a cell?Transcription Factors A protein that binds to DNA & blocks synthesis12. What is a TATA box?7-nucleotide promotor13. What is “sonic hedgehog” an example of?A gene that contro
8.1. IDENTIFYING DNA AS THE GENETIC MATERIAL. Reinforcement. KEY CONCEPT. DNA was identified as the genetic material through a series of experiments. A series of experiments helped scientists recognize that DNA is the genetic material. One of the earliest was done by Frederick Griffith wh
May 02, 2018 · D. Program Evaluation ͟The organization has provided a description of the framework for how each program will be evaluated. The framework should include all the elements below: ͟The evaluation methods are cost-effective for the organization ͟Quantitative and qualitative data is being collected (at Basics tier, data collection must have begun)
Silat is a combative art of self-defense and survival rooted from Matay archipelago. It was traced at thé early of Langkasuka Kingdom (2nd century CE) till thé reign of Melaka (Malaysia) Sultanate era (13th century). Silat has now evolved to become part of social culture and tradition with thé appearance of a fine physical and spiritual .
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Chính Văn.- Còn đức Thế tôn thì tuệ giác cực kỳ trong sạch 8: hiện hành bất nhị 9, đạt đến vô tướng 10, đứng vào chỗ đứng của các đức Thế tôn 11, thể hiện tính bình đẳng của các Ngài, đến chỗ không còn chướng ngại 12, giáo pháp không thể khuynh đảo, tâm thức không bị cản trở, cái được
2. At the end of DNA replication, (four/two) new strands of DNA have been produced, giving a total of (four/six) strands of DNA. 3. New DNA is replicated in strands complementary to old DNA because production of new DNA follows the rules of (base pairing/the double helix). Identifying Structures On the lines corresponding to the numbers on the .
Genetic transformation and DNA DNA is the genetic material in bacterial viruses (phage) The base-pairing rule DNA structure. 2. Basis for polarity of SS DNA and anti-parallel complementary strands of DNA 3. DNA replication models 4. Mechanism of DNA replication: steps and molecular machinery
