PLB 115 1st Edition Lecture 3The Origin of LifePrevious Notes’ OutlineI. Biology defined & importance explainedII. Scientific MethodIII. ExperimentationIV. Theories & Laws (& Pseudoscience)V. Example Experiment: Song birds & singing behaviorsCurrent Notes’ OutlineI.Characteristics of Living ThingsII. Levels of Organization in BiologyIII. Theories about Origin of Life (general)IV. Theories of Origin of Life on EarthV. Earth’s Early AtmosphereVI. Formation of CellsVII. Stanley Miller’s ExperimentVIII. Ideas about Formation of Organic Molecules into Complex MacromoleculesIX. RNA as First Genetic Materiala. Steps for Development of DNA-RNA Genetic SystemX. Development of MembranesCharacteristics of Living ThingsMetabolic processes- Obtain& store energy in chemical bonds in ofingested nutrients Generative processesThese 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.- Grow by increasing the number of cells, reproduce sexually/asexuallyResponsive processes: Organisms react to changes in their environment- Irritability: ability to recognize that something in its surroundings has changed (a stimulus) &quicklyrespondEvolution- Changes (genetic & appearance) in a population over timeControl processes- Carry out metabolic processes in correct ordero Coordination: Enzymes coordinate metabolic reactionsRegulation- Enzymes regulated in order to maintain homeostasisUnique structural organization- Organisms made of(many) cellsLevels of Organization in BiologyOrgan system: Set of several organs that perform aparticular taskOrgan: Several tissues thatperform a particular taskTissue: Several cells thatperform a particular taskCell: Simplest unit of lifeMolecules: A specificarrangements of atomsAtoms: Fundamentalunits of matterBiosphere: Worldwide ecosystemEcosystem: Communitiesthat interact with oneanother in a particularplaceCommunities: Populationsof different organismsinteracting with each other in a particular place at a particular timePopulation: Group ofindividual organisms in aparticular placeOrganism: An independent living unitTheories aboutOrigin of LifeSpontaneous Generation: Living things came from non-living things- By: Aristotle, accepted until 17th Centuryo Ex: Maggots from rotten meat, frogs from damp mudBiogenesis: Living things can only come from pre-existing living things- By: Redi’s experiments that rejected spontaneous generation as maggots only found in rotten meat uncovered & no maggots found in covered rotten meatNeedham,Spallazani, Pasteur’s ExperimentsNeedham: Spontaneous generationo Mutton broth in containers sealed with cork Became cloudy with microorganisms yet sealed & boiledSpallazani: Biogenesis- Same experiment as above but REALLY sealed containers by melting glass top & containers in boiling watero Result: Sealed containers had no bacteria & containers with broken glass didPasteur:- Same experiment but used flasks with long & curved necks (allow oxygen but not bacteria in)o Result: Bacteria only in flasks with broken necksTheories of Origin of Life on Earth- Panspermia: Life came from outside earth, transported to eartho Evidence: Meteorites from Mars containing organic molecules & exploration of Mars discovered signs of old bodies of water that may have once supported life- Abiogenesis: Life came from chemical reactions of inorganic matter that created organic moleculeso Evidence: Earth’s temperature range allows water to exist in liquid form on its surface Early atmosphere lacked oxygen & experiments show organic molecules can be produced from inorganic onesin an atmosphere without oxygen (reducing atmosphere)- *Reducing atmosphere= IMPORTANT b/c allowed organic molecules to join with each other instead of joining with oxygen& after forming in atmosphere organic molecules would’vegone from the air into oceans by rain. In ocean, molecules would’ve reacted with each other & formed complex molecules. - Earth was hotter in past & primitive Bacteria survive in extreme environmentsEarth’s Early Atmosphere- Thermonuclear reactions made the earth HOT, creating molten core encased by a thin outer crust as Earth cooledo Cooling allowed water to condense & fall as rain to form bodies of waterFormation of Cells- All living things bodies’ contain: cells with outer membranes, nucleic acids as genetic material, metabolism regulated by enzymes- Early cells had to form/have: Complex organic molecules from simple inorganic ones, genetic material that self-replicated, enzymes, membranes to separate genetic material & organicmolecules from surroundings, method to obtain energyStanley Miller’s Experiment- Replicated earth’s early atmosphere to see if organic molecules could’ve formed from inorganic oneso Had apparatus with chemicals in earth’s atmosphere, electrical sparks & heating gaveenergy, heated & cooled in cycle mimicking water cycle Result: Amino acids & sugars (organic molecules) found in waterIdeas about Formation of Organic Molecules into Complex Macromolecules1) Evaporation of water from isolated oceans caused concentration ofmolecules2) Freezing causedconcentration of molecules3) Clay particles caused aggregation & concentration of organic moleculesRNA as First (original) Genetic Material- DNA too complicated & requires enzymes not yet present in early Eartho Evidence for RNA:Some viruses use RNA as their genetic material to store genetic information, mutate, replicate themselves, & serve as catalysts (ribozymes)for some reactionsSteps for Development of DNA-RNA Genetic System- DNA replaces RNA as chosen genetic material- DNA responsible for making RNA- RNA control protein synthesis- Proteins become enzymes- Membranes & other cell structures involved in cell reproduction Development of Membranes- Oparin’s suggestion: Membranes= collection of organic molecules surrounded by a film of water (coacervates)- Hypothesis #2: Cells began as collections of organic molecules with a double-layered boundary - Hypothesis #3: Membranes formed from lipids interacting with