Bio 2.1 Final Exam Study Guide.pdf

Bio 2.1 Final Exam Study Guide.pdf - Exam#1 Concepts 1 What...

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Unformatted text preview: Exam​ ​#1​ ​Concepts 1. What​ ​does​ ​it​ ​mean​ ​to​ ​say​ ​science​ ​is​ ​provisional​ ​and​ ​that​ ​proof​ ​is​ ​relative​ ​to​ ​the​ ​evidence​ ​available at​ ​that​ ​time?​ ​You​ ​should​ ​be​ ​able​ ​to​ ​relate​ ​this​ ​to​ ​several​ ​of​ ​the​ ​topics​ ​discussed​ ​this​ ​term. i​ s​ ​provisional​ ​because​ ​there​ ​are​ ​no​ ​absolutes​ ​in​ ​science.​ ​Nothing​ ​can​ ​be proven​ ​with​ ​absolute​ ​certainty,​ ​but​ ​supported​ ​with​ ​evidence.​ ​Proof​ ​is​ ​relative​ ​to​ ​the evidence​ ​available​ ​at​ ​the​ ​time​ ​because​ ​technology​ ​is​ ​advancing​ ​and​ ​as​ ​this happens​ ​ideas​ ​became​ ​more​ ​accepted​ ​than​ ​before​ ​because​ ​there​ ​is​ ​more​ ​certain evidence​ ​to​ ​back​ ​it​ ​up.​ ​Robert​ ​Hooke​ ​had​ ​limited​ ​technology​ ​compared​ ​to Theodore​ ​Schwann​ ​(every​ ​part​ ​of​ ​animal​ ​looked​ ​at​ ​was​ ​made​ ​of​ ​cells)​ ​and Matthias​ ​Schleiden​ ​(every​ ​part​ ​of​ ​plant​ ​looked​ ​at​ ​was​ ​made​ ​out​ ​of​ ​cells)​ ​who​ ​had improved​ ​microscopes,​ ​sites,​ ​and​ ​staining.These​ ​advancements​ ​allow​ ​the​ ​cell theory​ ​to​ ​develop​ ​because​ ​there​ ​was​ ​evidence​ ​to​ ​support​ ​that​ ​cells​ ​were​ ​the​ ​basic unit​ ​of​ ​life​ ​and​ ​all​ ​living​ ​things​ ​were​ ​composed​ ​of​ ​cells.​ ​This​ ​is​ ​compared​ ​to​ ​Hooke who​ ​used​ ​technology​ ​to​ ​view​ ​the​ ​water​ ​passages​ ​in​ ​the​ ​cork​ ​involved​ ​in​ ​plant growth,​ ​but​ ​could​ ​calculate​ ​from​ ​his​ ​work​ ​what​ ​the​ ​cell​ ​was​ ​composed​ ​with. ​Science​ ​Our​ ​understanding​ ​of​ ​life​ ​is​ ​constantly​ ​changing​ ​as​ t​ echnology​​ ​and​ ​collaboration​​ ​allow for​ ​new​ ​means​ ​to​ ​answer​ ​old​ ​questions.​ ​What​ ​we​ ​know​ ​today​ ​and​ ​think,​ ​may​ ​change tomorrow.​ ​This​ ​is​ ​due​ ​to​ ​technology,​ ​improvements​ ​in​ ​technology​ ​helps​ ​us​ ​think​ ​in different​ ​ways,​ ​ways​ ​we​ ​view​ ​DNA​ ​today​ ​was​ ​not​ ​possible​ ​15​ ​years​ ​ago.​ ​For​ ​example, now​ ​we​ ​can​ ​sequence​ ​our​ ​own​ ​genes​ ​today,​ ​before​ ​we​ ​couldn’t.​ ​Science​ ​is​ ​an​ ​ongoing process. a. Relating​ ​to​ ​the​ ​Cell​ ​Theory:​ ​A​ ​specific​ ​example​ ​of​ ​this​ ​comes​ ​with​ ​the​ ​nerve​ ​cells, they​ ​were​ ​thought​ ​to​ ​be​ ​an​ ​outlier​ ​during​ ​the​ ​development​ ​of​ ​the​ ​cell​ ​theory​ ​due to​ ​its​ ​complexity.​ ​When​ ​golgi​ ​used​ ​the​ ​black​ ​reaction​ ​he​ ​discovered​ ​the​ ​structure of​ ​a​ ​neuron​ ​and​ ​thought​ ​that​ ​the​ ​cells​ ​were​ ​directly​ ​connected​ ​to​ ​one​ ​another. But​ ​the​ ​development​ ​of​ ​the​ ​electron​ ​microscope,​ ​scientists​ ​discovered​ ​the synapses​ ​between​ ​nerve​ ​cells​ ​.​ ​This​ ​is​ ​a​ ​demonstration​ ​of​ ​the​ ​process​ ​of scientific​ ​discovery.​ ​Science​ ​is​ ​provisional​ ​because​ ​it​ ​is​ ​based​ ​on​ ​facts​ ​and observable​ ​truths​ ​that​ ​can​ ​only​ ​happen​ ​when​ ​the​ ​proper​ ​experiment​ ​and​ ​tools needed​ ​for​ ​an​ ​experiment​ ​are​ ​available. 2. Scientific​ ​evidence​ ​suggests​ ​that​ ​all​ ​living​ ​things​ ​share​ ​a​ ​common​ ​ancestor​ ​(the​ ​unity​ ​of​ ​life).​ ​What evidence​ ​supports​ ​this​ ​statement​ ​that​ ​all​ ​living​ ​organisms​ ​are​ ​related? a. -Darwin​ ​saw​ ​anatomical​ ​similarities b. -similarities​ ​between​ ​alive​ ​and​ ​extinct​ ​species c. -Most​ ​evidence​ ​that​ ​all​ ​life​ ​is​ ​all​ ​related​ ​has​ ​to​ ​do​ ​with​ ​our​ ​DNA​ ​and​ ​RNA,​ ​since all​ ​things​ ​have​ ​it.​ ​RNA​ ​is​ ​very​ ​critical​ ​to​ ​life​ ​but​ ​evolves​ ​very​ ​slowly,​ ​giving scientists​ ​the​ ​opportunity​ ​to​ ​go​ ​back​ ​and​ ​look​ ​at​ ​homologies​ ​or​ ​relationships between​ ​distantly​ ​related​ ​organisms.​ ​Also​ ​with​ ​modern​ ​technology​ ​we​ ​are​ ​able​ ​to go​ ​back​ ​and​ ​compare​ ​DNA.​ ​Both​ ​DNA​ ​and​ ​RNA,​ ​this​ ​has​ ​made​ ​looking​ ​at​ ​our genes​ ​very​ ​useful​ ​for​ ​determining​ ​evolutionary​ ​relationships. ● ● ● ● All​ ​living​ ​organisms​ ​have​ ​DNA/RNA​ ​(use​ ​the​ ​same​ ​code) All​ ​living​ ​organisms​ ​use​ ​ATP​ ​-​ ​ATP​ ​synthase All​ ​living​ ​things​ ​have​ ​cell​ ​membranes​ ​(ex.​ ​Phospholipid​ ​bilayer) All​ ​living​ ​things​ ​have​ ​ribosomes​ ​and​ ​synthesize​ ​proteins s​ aw​ ​anatomical​ ​similarities​ ​between​ ​diverse​ ​species​ ​that​ ​were​ ​alive/extinct. Despite​ ​this,​ ​most​ ​evidence​ ​to​ ​support​ ​the​ ​unity​ ​of​ ​life​ ​comes​ ​from​ ​our​ ​DNA/RNA. As​ ​we​ ​know​ ​RNA​ ​is​ ​very​ ​critical​ ​to​ ​life​ ​but​ ​has​ ​evolved​ ​very​ ​slowly.​ ​This​ ​has allowed​ ​scientists​ ​to​ ​go​ ​global​ ​and​ ​look​ ​at​ ​similarities​ ​between​ ​distantly​ ​related organisms,​ ​make​ ​genes​ ​very​ ​useful​ ​for​ ​determining​ ​evolutionary​ ​relationships. Additionally​ ​we​ ​are​ ​now​ ​able​ ​to​ ​look​ ​at​ ​DNA​ ​sequences​ ​for​ ​comparison. ​Darwin​ ​ ​the​ ​biggest​ ​unifying​ ​characteristic​ ​among​ ​all​ ​domains​ ​is​ ​that​ ​they​ ​all​ ​share​ ​a​ ​genetic​ ​code.​ ​They​ ​use the​ ​same​ ​letters​ ​and​ ​if​ ​you​ ​put​ ​them​ ​in​ ​certain​ ​sequences,​ ​they​ ​have​ ​the​ ​same​ ​results.​ ​Living​ ​things also​ ​have​ ​the​ ​same​ ​building​ ​blocks​ ​in​ ​common​ ​(amino​ ​acids)​ ​and​ ​they​ ​use​ ​ATP​ ​for​ ​energy. These​ ​characteristics​ ​show​ ​that​ ​life​ ​evolved​ ​from​ ​one​ ​single​ ​cell​ ​because​ ​living​ ​organisms​ ​all​ ​seem to​ ​be​ ​a​ ​variation​ ​of​ ​the​ ​same​ ​building​ ​blocks.​ ​Some​ ​are​ ​simpler,​ ​and​ ​others​ ​are​ ​more​ ​complex,​ ​but the​ ​more​ ​complex​ ​ones​ ​must​ ​have​ ​evolved​ ​over​ ​a​ ​long​ ​period​ ​of​ ​time​ ​through​ ​mutations​ ​that​ ​just happened​ ​to​ ​help​ those​ ​organisms​ ​thrive​ ​in​ ​their​ ​environment.​ ​It​ ​is​ ​unlikely​ ​that​ ​any​ ​complex organism​ ​magically​ ​arranged​ ​themselves​ ​into​ ​a​ ​functioning​ ​self-sustaining​ ​and​ ​self-replicating system,​ ​when​ ​nature​ ​favors​ ​disorder.​ ​They​ ​must​ ​have​ ​come​ ​from​ ​simpler​ ​organisms,​ ​the​ ​simplest one​ ​being​ ​the​ ​cell. 3. Discuss​ ​the​ ​general​ ​steps​ ​needed​ ​for​ ​life​ ​to​ ​emerge​ ​from​ ​inorganic​ ​molecules. -(CO2)​ ​inorganics​ ​to​ ​organic​ ​(CH) Hydrothermal​ ​events​ ​(gradient)​:​ ​right​ ​next​ ​to​ ​the​ ​hydrothermal​ ​vents​ ​it was​ ​too​ ​hot,​ ​and​ ​too​ ​far​ ​from​ ​the​ ​hydrothermal​ ​vents​ ​it​ ​was​ ​too​ ​cold,​ ​life could​ ​have​ ​potentially​ ​arose​ ​at​ ​a​ ​certain​ ​distant​ ​from​ ​the​ ​vents​ ​which provided​ ​an​ ​ideal​ ​temp​ ​and​ ​environment.​ ​(Goldilocks​ ​effect) ● Extraterrestrial​:​ ​meteorites​ ​brought​ ​life,​ ​crash​ ​would​ ​result​ ​in​ ​new compounds/molecules​ ​(form​ ​new​ ​bonds​ ​and​ ​break​ ​bonds) ● Lightning​ ​striking​ ​the​ ​oceans​-​ ​Stanley​ ​miller​ ​recreated​ ​this:electrical voltage.​ ​Empirical​ ​evidence.​​ ​Reducing​ ​Environment​ ​(favoring​ ​synthesis) ● Deep​ ​Sea​ ​Vents​ ​-​ ​underwater​ ​volcanoes ○ Has​ ​potentially​ ​favorable​ ​temperatures ○ Is​ ​a​ ​reducing​ ​environment ○ Heat​ ​in​ ​the​ ​form​ ​of​ ​volcanoes/gas -Simple​ ​to​ ​complex ● Clays,​ ​tide​ ​pools;​ ​tide​ ​comes​ ​in​ ​washing​ ​up​ ​simple​ ​organic​ ​matter,​ ​water evaporates​ ​now​ ​you​ ​have​ ​concentration​ ​of​ ​simple​ ​organic​ ​particles. ● Increase​ ​concentration -complex​ ​to​ ​life ● Compartment ● Self​ ​replication ● 4. Compare​ ​and​ ​contrast​ ​Eukarya,​ ​Bacteria,​ ​and​ ​Archaea​ ​and​ ​discuss​ ​why​ ​horizontal​ ​gene​ ​transfer makes​ ​using​ ​molecular​ ​data​ ​to​ ​determine​ ​evolutionary​ ​relationships​ ​between​ ​these​ ​domains challenging. 5. Using​ ​examples,​ ​explain​ ​the​ ​concept​ ​“structure​ ​suggests​ ​function”​ ​as​ ​it​ ​relates​ ​to​ ​biological molecules​ ​and​ ​cells. 6. Explain​ ​the​ ​endosymbiotic​ ​theory​ ​used​ ​to​ ​explain​ ​the​ ​origin​ ​of​ ​mitochondria​ ​and​ ​chloroplasts.​ ​You should​ ​be​ ​able​ ​to​ ​list​ ​several​ ​lines​ ​of​ ​evidence​ ​supporting​ ​this​ ​theory. Endosymbiosis​ ​is​ ​the​ ​process​ ​in​ ​which​ ​certain​ ​unicellular​ ​organisms​ ​engulf​ ​other​ ​cells, Which​ ​become​ ​organelles​ ​in​ ​the​ ​host​ ​cell.​ ​Structural,​ ​biochemical,​ ​and​ ​DNA​ ​sequence data​ ​indicate​ ​that​ ​the​ ​first​ ​eukaryotes​ ​acquired​ ​mitochondria​ ​by​ ​engulfing​ ​an​ ​aerobic​ ​prokaryote. The​ ​endosymbiosis​ ​theory​ ​states​ ​that​ ​cells​ ​were​ ​created​ ​by​ ​engulfing​ ​mitochondria​ ​and​ ​by​ ​using the​ ​excess​ ​power​ ​that​ ​they​ ​produced,​ ​created​ ​the​ ​other​ ​organelles​ ​that​ ​are​ ​present​ ​in Eukaryotic​ ​cells​ ​today. Evidence ● A​ ​double​ ​membrane​ ​in​ mitochondria ● Mitochondria​ ​has​ ​bacterial​ ​DNA​ ​(circular) ● Mitochondria​ ​divides​ ​by​ ​binary​ ​fission ● Mitochondria​ ​have​ ​70-S​ ​ribosomes,​ ​but​ ​eukaryotes​ ​have​ ​80-S ● Mitochondria​ ​are​ ​used​ ​for​ ​energy Mitochondria​ ​came​ ​first,​ ​before​ ​chloroplasts;​ ​we​ ​have​ ​reason​ ​to​ ​believe​ ​this​ ​is​ ​the​ ​case​ ​because all​ ​eukaryotic​ ​cell​ ​contains​ ​mitochondria,​ ​but​ ​not​ ​every​ ​one​ ​contains​ ​chloroplasts. 7. Explain​ ​how​ ​substrate​ ​concentration​ ​affects​ ​the​ ​rate​ ​of​ ​an​ ​enzyme-catalyzed​ ​reaction.​ ​Describe how​ ​this​ ​response​ ​to​ ​substrate​ ​concentration​ ​is​ ​affected​ ​by​ ​competitive​ ​and​ ​noncompetitive inhibitors. 8. Describe​ ​how​ ​allosteric​ ​regulators​ ​may​ ​inhibit​ ​or​ ​stimulate​ ​the​ ​activity​ ​of​ ​an​ ​enzyme​ ​and​ ​how​ ​this can​ ​be​ ​used​ ​by​ ​the​ ​cell​ ​to​ ​regulate​ ​metabolic​ ​pathways. -By​ ​inducing​ ​shape​ ​change​ ​so​ ​something​ ​can’t​ ​bind​ ​to​ ​active​ ​site. Glycolysis=pyruvate--->acetyl​ ​coa--->citric​ ​acid​ ​cycle​ ​(produces​ ​NADH​ ​and​ ​FADH2)​ ​-->oxidative phosphorylation=​ ​ATP------->​ ​if​ ​nothing​ ​is​ ​taking​ ​ATP,​ ​ATP​ ​can​ ​bind​ ​with​ ​phosphofructokinase Exam​ ​#2​ ​Concepts 9. Explain​ ​how​ ​various​ ​molecules​ ​(hydrophobic,​ ​small/large​ ​charged​ ​or​ ​polar,​ ​etc.)​ ​are​ ​transported across​ ​membranes. The​ ​cell​ ​transports​ ​CO​2​​ ​Ca​ ​and​ ​other​ ​small/​ ​nonpolar​ ​substances​ ​ ​through​ ​simple​ ​diffusion. Transport​ ​of​ ​larger​ ​molecules​ ​like​ ​glucose​ ​AA,​ ​and​ ​ions​ ​require​ ​transport​ ​proteins​ ​and​ ​facilitated diffusion.​ ​Transmembrane​ ​proteins​ ​create​ ​a​ ​water​ ​filled​ ​pore​ ​through​ ​which​ ​ions​ ​and​ ​small hydrophilic​ ​molecules​ ​can​ ​pass​ ​via​ ​diffusion​ ​with​ ​their​ ​concentration​ ​gradient.​ ​There​ ​channels can​ ​be​ ​opened​ ​or​ ​closed​ ​based​ ​off​ ​of​ ​the​ ​needs​ ​of​ ​the​ ​cells.​ ​Transmembrane​ ​porters​ ​(transporters) use​ ​active​ ​transport​ ​which​ ​requires​ ​ATP​ ​to​ ​force​ ​ions​ ​or​ ​small​ ​molecules​ ​through​ ​the​ ​membrane against​ ​their​ ​concentration​ ​gradient. Simple​ ​Diffusion​ ​(a):​ ​passive,​ ​no​ ​ATP,​ ​concentration​ ​grad​ ​is​ ​potential​ ​energy​ ​used.​ ​Small, nonpolar​ ​molecules​ ​(Oxygen,​ ​nitrogen,​ ​carbon​ ​dioxide) Channel-mediated​ ​Facilitated​ ​Diffusion​ ​(b):​ ​Transport​ ​proteins​ ​with​ ​hydrophilic​ ​core​ ​all diffusion​ ​of​ ​polar​ ​molecules​ ​(water)​ ​to​ ​pass,​ ​no​ ​ATP,​ ​cell​ ​regulated Carrier-mediated​ ​Facilitated​ ​Diffusion​ ​(c):​ ​Transport​ ​protein​ ​changes​ ​shape​ ​when​ ​large​ ​polar molecules​ ​(glucose)​ ​bind​ ​to​ ​active​ ​site. ● Hydrophobic​ ​small​ ​molecules​ ​are​ ​passively​ ​transported​ ​through​ ​the​ ​nonpolar​ ​membrane ● Large​ ​molecules​ ​are​ ​often​ ​rejected​ ​from​ ​moving​ ​through​ ​the​ ​membrane​ ​in​ ​any​ ​way ● Small​ m ​ olecules​ ​usually​ ​get​ ​across​ ​is​ ​one​ ​of​ ​the​ ​three​ ​ways​ ​(passively,​ ​through​ ​a​ ​canal, or​ ​actively​ ​through​ ​transport​ ​proteins) ● Hydrophilic​ ​molecules​ ​need​ ​canals​ ​with​ ​a​ ​polar​ ​inside​ ​or​ ​transport​ ​proteins​ ​to​ ​move through​ ​membranes ● Charged​ ​molecules​ ​(ions)​ ​need​ ​canals​ ​and​ ​transport​ ​proteins​ ​as​ ​well 10. Using​ ​examples,​ ​describe​ ​facilitated​ ​diffusion,​ ​primary​ ​active​ ​transport,​ ​and​ ​secondary​ ​active transport​ ​(antiporter/symporter).​ ​Relate​ ​these​ ​to​ ​the​ ​structure​ ​and​ ​function​ ​of​ ​carriers​ ​and​ ​channels. 11. Explain​ ​how​ ​cells​ ​establish,​ ​maintain,​ ​and​ ​use​ ​electrochemical​ ​gradients.​ ​Relate​ ​this​ ​to​ ​cellular energy​ ​and​ ​cell​ ​signaling. 12. Compare​ ​and​ ​contrast​ ​the​ ​structures​ ​and​ ​functions​ ​of​ ​microtubules,​ ​intermediate​ ​filaments,​ ​and actin​ ​filaments. 13. Explain​ ​how​ ​the​ ​cell​ ​uses​ ​cytoskeletal​ ​elements​ ​(microtubules​ ​or​ ​actin​ ​filaments)​ ​and​ ​motor proteins​ ​(dynein/kinesin​ ​or​ ​myosin)​ ​in​ ​intracellular​ ​transport​ ​and​ ​muscle​ ​contractions. 14. Discuss​ ​muscle​ ​contractions​ ​as​ ​an​ ​example​ ​of​ ​the​ ​interconnectedness​ ​of​ ​cellular​ ​structures​ ​and processes.​ ​You​ ​should​ ​be​ ​able​ ​to​ ​relate​ ​intracellular​ ​transport,​ ​membrane​ ​structure/transport, protein​ ​structure/function/regulation,​ ​cellular​ ​energy,​ ​and​ ​cell​ ​signaling​ ​to​ ​muscle​ ​contractions. Remember​ ​that​ ​this​ ​example​ ​was​ ​used​ ​to​ ​tie​ ​these​ ​complex​ ​processes​ ​together​. 15. Explain​ ​how​ ​an​ ​energetically​ ​favorable​ ​reaction​ ​can​ ​be​ ​used​ ​to​ ​drive​ ​an​ ​energetically​ ​unfavorable reaction.​ ​Be​ ​able​ ​to​ ​relate​ ​this​ ​concept​ ​to​ ​other​ ​aspects​ ​of​ ​cell/molecular​ ​biology. 16. Summarize​ ​each​ ​step​ ​in​ ​cellular​ ​respiration​ ​(glycolysis,​ ​pyruvate​ ​processing,​ ​citric​ ​acid​ ​cycle,​ ​ETC) and​ ​photosynthesis​ ​(light​ ​reaction​ ​and​ ​Calvin​ ​cycle)​ ​highlighting​ ​the​ ​flow​ ​of​ ​energy​ ​(ΔG)​ ​and describe​ ​where​ ​in​ ​the​ ​cell​ ​it​ ​occurs. 17. Explain​ ​in​ ​general​ ​terms​ ​how​ ​redox​ ​reactions​ ​are​ ​involved​ ​in​ ​energy​ ​exchanges.​ ​Relate​ ​this​ ​to​ ​cell respiration​ ​and​ ​photosynthesis. 18. Describe​ ​the​ ​similarities​ ​and​ ​differences​ ​between​ ​oxidative​ ​phosphorylation​ ​(mitochondria)​ ​and photophosphorylation​ ​(chloroplasts). 19. List​ ​and​ ​briefly​ ​describe,​ ​using​ ​examples,​ ​the​ ​three​ ​stages​ ​of​ ​cell​ ​signaling. 20. Explain​ ​how​ ​one​ ​signal​ ​can​ ​promote​ ​different​ ​responses​ ​in​ ​different​ ​cells.​ ​For​ ​example,​ ​epinephrine causes​ ​the​ ​heart​ ​to​ ​beat​ ​faster​ ​while​ ​causing​ ​the​ ​liver​ ​to​ ​release​ ​glucose. Genetic​ ​Material 21. Explain​ ​how​ ​the​ ​experiments​ ​performed​ ​by​ ​the​ ​following​ ​scientists​ ​provided​ ​evidence​ ​that​ ​DNA​ is the​ ​genetic​ ​material: a. Frederick​ ​Griffith:​ ​He​ ​did​ ​the​ ​whole​ ​experiment​ ​with​ ​bacteria​ ​and​ ​mice.​ ​Used​ ​two​ ​strains of​ ​bacteria,​ ​R​ ​and​ ​S.​ ​His​ ​purpose​ ​was​ ​to​ ​develop​ ​a​ ​vaccine​ ​against​ ​pneumonia.​ ​Tried injecting​ ​mice​ ​with​ ​heat-killed​ ​S​ ​bacteria.​ ​The​ ​heat​ ​killed​ ​S​ ​bacteria​ ​don't​ ​cause​ ​disease​ ​in mice.​ ​When​ ​harmless​ ​R​ ​bacteria​ ​was​ ​combined​ ​with​ ​harmless​ ​heat-killed​ ​S​ ​bacteria​ ​and injected​ ​into​ ​a​ ​mouse,​ ​the​ ​mouse​ ​developed​ ​pneumonia​ ​and​ ​died,​ ​but​ ​also​ ​found​ ​the​ ​blood​ ​in the​ ​mouse​ ​contained​ ​living​ ​S​ ​bacteria.​ ​So,​ ​he​ ​concluded​ ​that​ ​the​ ​R-strain​ ​bacteria​ ​must​ ​have taken​ ​up​ ​a​ ​transforming​ ​principle​ ​from​ ​the​ ​heat​ ​killed​ ​S​ ​bacteria​ ​which​ ​allowed​ ​them​ ​to transform​ ​into​ ​smooth​ ​coated​ ​bacteria​ ​and​ ​become​ ​harmful. b. Oswald​ ​Avery,​ ​Maclyn​ ​McCarty,​ ​and​ ​Colin​ ​MacLeod:​ ​Wanted​ ​to​ ​identify​ ​“transforming principle.”​ ​Began​ ​with​ ​large​ ​cultures​ ​of​ ​heat​ ​killed​ ​S​ ​cells​ ​and​ ​purified​ ​the​ ​the​ ​transforming principle​ ​by​ ​washing​ ​away,​ ​separating​ ​out,​ ​or​ ​destroying​ ​other​ ​cellular​ ​components.​ ​They were​ ​able​ ​to​ ​obtain​ ​a​ ​small​ ​amount​ ​of​ ​highly​ ​purified​ ​transforming​ ​principle​ ​which​ ​they​ ​were able​ ​to​ ​analyze.​ ​They​ ​suggested​ ​that​ ​it​ ​was​ ​DNA.​ ​What​ ​they​ ​found​ ​out: ● The​ ​substance​ ​gave​ ​a​ ​negative​ ​result​ ​in​ ​chemical​ ​test​ ​known​ ​to​ ​detect proteins,​ ​but​ ​a​ ​positive​ ​result​ ​in​ ​chemical​ ​test​ ​known​ ​to​ ​detect​ ​DNA. ● The​ ​elemental​ ​composition​ ​of​ ​the​ ​purified​ ​transforming​ ​principle​ ​closely resembled​ ​DNA​ ​in​ ​its​ ​ratio​ ​of​ ​nitrogen​ ​and​ ​phosphorus. ● Protein​ ​and​ ​RNA​ ​degrading​ ​enzymes​ ​had​ ​little​ ​effect​ ​on​ ​the​ ​transforming principle,​ ​but​ ​enzymes​ ​able​ ​to​ ​degrade​ ​DNA​ ​eliminated​ ​the​ ​transforming activity. Result:​ ​everything​ ​pointed​ ​to​ ​DNA​ ​as​ ​the​ ​transforming​ ​principle. c. Alfred​ ​Hershey​ ​and​ ​Martha​ ​Chase:​ ​used​ ​radioactive​ ​isotopes​ ​to​ ​label​ ​proteins​ ​vs.​ ​DNA -studied​ ​bacteriophage​ ​(virus​ ​that​ ​targets​ ​bacteria)​ ​phage​ ​has​ ​protein​ ​capsule​ ​and​ ​DNA in​ ​middle.​ ​Learned​ ​that​ ​genetic​ ​material​ ​goes​ ​into​ ​host​ ​and​ ​the​ ​capsule​ ​stays​ ​behind Batch​ ​1:​ ​radioactive​ ​sulfur-->in​ ​protein​ ​but​ ​not​ ​DNA/​ ​radioactive​ ​phosphorus--->in​ ​DNA,​ ​but not​ ​in​ ​protein.​ ​Now​ ​they​ ​can​ ​tag​ ​these​ ​and​ ​see​ ​which​ ​goes​ ​where.​ ​They​ ​found​ ​that​ ​the​ ​sulfur was​ ​up​ ​in​ ​the​ ​supernatant​ ​(proteins​ ​always​ ​on​ ​top)​ ​and​ ​DNA​ ​was​ ​found​ ​in​ ​the​ ​bottom. d. Erwin​ ​Chargaff:​ ​A=T,​ ​C=G Chargaff’s​ ​Rules: 1. Base​ ​composition​ ​varies​ ​between​ ​species 2. Within​ a ​ ​ ​species,​ ​the​ ​number​ ​of​ ​A​ ​and​ ​T​ ​bases​ ​are​ ​equal​ ​and​ ​the​ ​number​ ​of​ ​C​ ​and​ ​G​ ​bases​ ​are equal *basis​ ​remained​ ​unexplained​ ​until​ ​discovery​ ​of​ ​the​ ​double​ ​helix 22. Explain​ ​how​ ​Watson​ ​and​ ​Crick​ ​deduced​ ​the​ ​structure​ ​of​ ​DNA​ ​and​ ​describe​ ​the​ ​evidence​ ​they​ ​used. Explain​ ​the​ ​significance​ ​of​ ​the​ ​research​ ​of​ ​Rosalind​ ​Franklin. Watson​ ​saw​ ​x-ray​ ​diffraction​ ​image​ ​of​ ​DNA​ ​(Rosalind​ ​Franklin’s) Discovered​ ​double​ ​helix​ ​structure​ ​of​ ​DNA​ ​since​ ​Watson​ ​was​ ​familiar​ ​with​ ​the​ ​type​ ​of​ ​x-ray diffraction​ ​pattern​ ​that​ ​helical​ ​molecules​ ​produce.​ ​They​ ​began​ ​building​ ​models​ ​that​ ​would conform​ ​to​ ​the​ ​x-ray​ ​measurements.​ ​From​ ​Franklin’s​ ​research,​ ​they​ ​knew​ ​she​ ​concluded​ ​that​ ​the sugar-phosphate​ ​backbones​ ​were​ ​on​ ​the​ ​outside​ ​of​ ​the​ ​DNA​ ​molecule Model​ ​for​ ​DNA​ ​replication: a.)​ ​parent​ ​molecule:​ ​has​ ​two​ ​complementary​ ​strands​ ​of​ ​DNA.​ ​Each​ ​base​ ​paired​ ​by​ ​hydrogen bonding​ ​with​ ​its​ ​specific​ ​partner,​ ​A-T​ ​and​ ​C-G b.)​ ​separation​ ​of​ ​strands:​ ​each​ ​parental​ ​strand​ ​can​ ​now​ ​serve​ ​as​ ​a​ ​template​ ​that​ ​determines​ ​the order​ ​of​ ​nucleotides​ ​along​ ​a​ ​new,​ ​complementary​ ​strand c.)​ ​“daughter”​ ​DNA​ ​molecules,​ ​each​ ​consisting​ ​of​ ​one​ ​parental​ ​strand​ ​and​ ​one​ ​new​ ​strand: complementary​ ​nucleotides​ ​line​ ​up​ ​and​ ​are​ ​connected​ ​to​ ​form​ ​sugar-phosphate​ ​backbones​ ​of​ ​new strands.​ ​Each​ ​“daughter”​ ​DNA​ ​molecule​ ​has​ ​one​ ​parental​ ​strand​ ​and​ ​one​ ​new​ ​strand 23. Describe​ ​the​ ​structure​ ​of​ ​DNA.​ ​Explain​ ​the​ ​base-pairing​ ​rule​ ​and​ ​describe​ ​its​ ​significance. DNA​ ​Replication​ ​and​ ​Repair 24. Describe​ ​the​ ​classic​ ​experiment​ ​by​ ​Matthew​ ​Meselson​ ​and​ ​Franklin​ ​Stahl.​ ​For​ ​each​ ​hypothesis (semiconservative,​ ​conservative,​ ​and​ ​dispersive)​ ​explain​ ​the​ ​predicted​ ​results. They​ ​tested​ ​if​ ​DNA​ ​replication​ ​followed​ ​a​ ​conservative,​ ​semi-conservative​ ​or​ ​dispersive​ ​model.​ ​They began​ ​with​ ​a​ ​flask​ ​with​ ​cultured​ ​bacteria​ ​in​ ​a​ ​liquid​ ​with​ ​a​ ​heavy​ ​isotope,​ ​N15.​ ​the​ ​bacteria​ ​was​ ​then transferred​ ​into​ ​another​ ​flask​ ​with​ ​a​ ​lighter​ ​isotope,​ ​N14.​ ​From​ ​that​ ​flask​ ​they​ ​extracted​ ​DNA​ ​from the​ ​bacteria​ ​and​ ​centrifuged​ ​each​ ​DNA​ ​sample​ ​to​ ​separate​ ​the​ ​different​ ​densities​ ​of​ ​DNA.​ ​After​ ​the first​ ​replication,​ ​the​ ​DNA​ ​sample​ ​results​ ​in​ ​a​ ​single​ ​strand​ ​about​ ​mid​ ​way​ ​between​ ​the​ ​test​ ​tube. After​ ​the​ ​second​ ​replication,​ ​there​ ​were​ ​two​ ​s...
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    Jill Tulane University ‘16, Course Hero Intern