Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37NSCI 314LIFE IN THE COSMOS4 – Basic Properties of Life and The Biochemistry of Life on EarthDr. Karen KolehmainenDepartment of Physics CSUSBhttp://physics.csusb.edu/~karen/WHAT IS LIFE?HARD TO DEFINE, BUT LET'S LIST SOME OF ITS PROPERTIES.NECESSARY PROPERTIES:–USES ENERGY–INTERACTS WITH ITS ENVIRONMENT–MAINTAINS A LOW ENTROPY (HIGH DEGREE OR ORDER OR COMPLEXITY) INTERNALLYLIKELY (BUT MAYBE NOT NECESSARY) PROPERTIES:–GROWS AND DEVELOPS–REPRODUCES–MUTATES AND EVOLVESREQUIREMENTS FOR LIFE MATTER:PRODUCED IN BIG BANG (H & He) AND STARS (HEAVIER ELEMENTS) ARE CERTAIN ELEMENTS NEEDED?STABLE ENERGY SOURCE:LOW MASS MAIN SEQUENCE STARS (OR SOMETHING ELSE?)PROTECTED ENVIRONMENT:PLANETARY OR LUNAR SURFACESPLANETARY OR LUNAR INTERIORSTHICK PLANETARY OR LUNAR ATMOSPHERESCHEMICAL SOLVENT (LIQUID): WATER (OR SOMETHING ELSE?)APPROPRIATE TEMPERATURE RANGE: NEEDED TO KEEP THE SOLVENT LIQUID (APPROXIMATELY 0 TO 100o C IF WATER IS THE LIQUID SOLVENT)IF IT’S TOO HOT, COMPLEX STRUCTURES ARE BROKEN APARTIF IT’S TOO COLD, INTERACTIONS ARE TOO SLOWSun Earth Earth’s Crust HydrogenHeliumOxygenCarbonNeonNitrogenMagnesiumSiliconIronSulfurArgonAluminumCalciumSodiumNickelChromiumPhosphorus90.99%8.870.0780.0330.0110.0100.0040.0030.0030.0020.00030.00030.00020.00020.00020.000030.00003OxygenIron SiliconMagnesiumSulfurNickel AluminumCalciumSodiumChromiumPhosphorus50%1714141.61.11.10.740.660.130.08OxygenSiliconAluminumIronCalciumSodiumPotassiumMagnesiumTitaniumHydrogenPhosphorusManganeseFluorineStrontiumSulfur47%288.15.03.62.82.62.10.440.140.100.100.0630.0380.026Earth’s Atmosphere Bacteria Human BeingsNitrogenOxygen ArgonCarbon**NeonHelium78%210.930.030.00180.00052HydrogenOxygenCarbonNitrogenPhosphorusSulfur63%296.41.40.120.06HydrogenOxygenCarbonNitrogenCalciumPhosphorusSulfur61%2610.52.40.230.130.13BOTTOM LINE:THE ELEMENTS THAT MAKE UP TERRESTRIAL LIVING ORGANISMS ARE VERY COMMON IN STARS AND IN THE INTERSTELLAR MATERIAL FROM WHICH STARS AND PLANETS ARE FORMED. IN LIVING THINGS, THE ATOMS OF THESE ELEMENTS ARE ORGANIZED IN ORGANIC MOLECULES, MANY OF WHICH ARE LARGE AND COMPLEX.ORGANIC MOLECULESMOLECULE: A COMBINATION OF TWO OR MORE ATOMSEXAMPLES: H2O CO2 CH4 NH3 H2 N2 O2 C2H5O2NORGANIC MOLECULE: A MOLECULE COMPOSED OF CARBON AND HYDROGEN ATOMS (AND OFTEN OTHER ELEMENTS ALSO) EXAMPLES: CH4 C2H5O2NMONOMER: A SIMPLE ORGANIC MOLECULE SUCH AS AN AMINO ACID, SIMPLE SUGAR, FATTY ACID, OR GENETIC BASEPOLYMER: A LARGE ORGANIC MOLECULE COMPOSED OF A CHAIN OF REPEATING MONOMERSEXAMPLES OF POLYMERSCARBOHYDRATES: STARCHES, CELLULOSE, SUCROSE.MONOMERS: SIMPLE SUGARS, GLUCOSELIPIDS: FATS, CHOLESTEROL, HORMONES, CELLULAR MEMBRANES.MONOMERS: FATTY ACIDSNUCLEIC ACIDS: DEOXYRIBONUCLEIC ACID (DNA) & RIBONUCLEIC ACID (RNA).MONOMERS: GENETIC BASESPROTEINS: STRUCTURAL PROTEINS FOR BONE, ORGANS, TISSUE, AND MEMBRANES; ENZYMES, CHEMICAL SENSORS AND TRANSPORTERS.MONOMERS: AMINO ACIDS LET’S EXAMINE NUCLEIC ACIDS AND PROTEINS IN MORE DETAIL.ORGANIC MOLECULESCARBON ATOMS OCCUPY CENTRAL POSITIONS IN MOST MONOMERS. WHEN THE MONOMERS COMBINE TO FORM POLYMERS, THE CARBON ATOMS FORM THE CENTRAL STRUCTURE OF THE CHAIN, WITH ATOMS OF OTHER ELEMENTS STUCK TO THE SIDES. H H H | | | C – C – C | | | H H HLIFE ON EARTH IS CARBON-BASED.BASIC FACTS ABOUT LIFE ON EARTHLIVING ORGANISMS ON EARTH ARE MADE OF CELLS. EXCEPTION: VIRUSESA CELL IS TINY DROP OF WATER AND VARIOUS ORGANIC MOLECULES, SURROUNDED BY A MEMBRANE. SOME CELLS CONTAIN CERTAIN STRUCTURES, TO BE DISCUSSED LATER. SOME ORGANISMS (e.g., BACTERIA) ARE SINGLE-CELLED, AND OTHER ORGANISMS (i.e., HUMANS) ARE MULTICELLULAR. A CELL CAN DIVIDE, RESULTING IN TWO CELLS.STRUCTURE OF PROTEINSA PROTEIN IS A LONG POLYMER MADE OF MONOMERS CALLED AMINO ACIDS.EACH PROTEIN IS COMPOSED OF A CHAIN OF HUNDREDS OF AMINO ACIDS.PROTEINS USED IN LIFE ON EARTH ARE FORMED FROM ONLY DIFFERENT 20 TYPES OF AMINO ACIDS. ADDITIONAL TYPES OF AMINO ACIDS EXIST AND COULD BE USED BY LIFE ELSEWHERE.PROTEIN STRUCTUREEXAMPLE:AA1—AA3—AA3—AA1—AA17—AA11—AA11—AA11 — AA2—AA9—AA9—AA9—AA9—AA9—AA10—AA15 — AA8—AA5—AA5—AA1—AA16—AA12—AA4—AA20 — AA19—AA7—AA3—AA5—…. CONTINUING ON FOR HUNDREDS MORE OF AMINO ACIDS.PROTEIN STRUCTURECHANGING EVEN ONE OF THE AMINO ACIDS OUT OF THE HUNDREDS IN THE CHAIN CHANGES THE PROTEIN.AA1—AA3—AA3—AA1—AA17—AA11—AA11—AA11 — AA2—AA9—AA9—AA9—AA9—AA9—AA10—AA15 — AA8—AA5—AA6—AA1—AA16—AA12—AA4—AA20 — AA19—AA7—AA3—AA5—…. CONTINUING ON FOR HUNDREDS MORE OF AMINO ACIDS.THIS IS NOW A DIFFERENT PROTEIN FROM THE ONE ON THE PREVIOUS SLIDE.NUMBER OF POSSIBLE PROTEINS EXAMPLE: IMAGINE A PROTEIN THAT CONSISTS OF A CHAIN OF 200 AMINO ACIDS.20200 = 10260 DIFFERENT PROTEINS ARE POSSIBLE.(NUMBER OF POSSIBLE ORDERINGS OF A CHAIN OF 200 AMINO ACIDS OF 20 DIFFERENT TYPES)IN COMPARISON, THE TOTAL NUMBER OF PROTONS, NEUTRONS, AND ELECTRONS IN THE ENTIRE UNIVERSE IS ESTIMATED TO BE LESS THAN 1090.ANOTHER PROTEIN OF A DIFFERENT LENGTH WOULD HAVE A SIMILARLY LARGE NUMBER OF POSSIBLE COMBINATIONS.EXAMPLE: A SEQUENCE OF 312 AMINO ACIDS WOULD RESULT IN 20312 = 10406 DIFFERENT POSSIBLE PROTEINS.CONSEQUENCE:EVEN IF EXTRATERRESTRIAL LIFE USES THE SAME 20 AMINO ACIDS AS LIFE ON EARTH …IT IS VERY UNLIKELY THAT ANY OF THE PROTEINS WILL BE THE SAME AS THOSE USED BY LIFE ON EARTH.THIS MAKES IT UNLIKELY THAT WE COULD EAT EACH OTHER'S FOOD, BE INFECTED BY EACH OTHER'S DISEASES, ETC.AMINO ACIDSAMINO ACIDS ARE THE MONOMERS THAT MAKE UP PROTEINS.AMINO ACIDS ARE FOUND:IN ALL TERRESTRIAL FORMS OF LIFE.IN METEORITES (ROCKS THAT FALL TO EARTH FROM SPACE).IN INTERSTELLAR CLOUDS OR NEBULAE.NOTE: AMINO ACIDS CAN BE PRODUCED BY NON-BIOLOGICAL CHEMICAL REACTIONS. THEREFORE, THE PRESENCE OF AMINO ACIDS DOESN’T NECESSARILY INDICATE THE PRESENCE OF LIFE.HANDEDNESS OF AMINO ACIDSEACH AMINO ACID CAN HAVE TWO “ISOMERS” OR MOLECULAR VERSIONS:L (LEVO- OR LEFT-HANDED) D (DEXTRO- OR RIGHT-HANDED)THE TWO
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