www.njctl.org AP Biology Emergence of Organic Molecules Emergence of Organic Molecules Early Earth and Early Universe Classwork 1. Briefly explain the biochemical experiment performed by Miller-Urey and its significance to the origin of living organisms. 2. The Earth is believed to be 4.5 billion years old. What evidence do scientists use to make this statement? 3. You are probably most familiar with the name Hubble from the Hubble telescope launched by NASA in 1990. What evidence did Edwin Hubble use to help support the Big Bang theory? 4. Where do scientist believe all the natural elements that make up the Earth originally came from? 5. Scientists have come up with the acronym LUCA. What do the letters stand for? Briefly describe the basis for this hypothesis. 6. Discuss the uniqueness of the chemical and physical properties of the water molecules, and the significance of these properties to life on Earth. 7. What sequence of events would occur in a lake as winter progresses, if solid water were more dense the liquid water, as is the case with most molecules? 8. Describe the two parts that make up a solution. 9. Living organisms use buffers to help maintain a steady pH in their internal environment. Human blood has buffers. The buffer contains a large reservoir of an acid and a base. When something is added to the blood the buffer will either bind with excess hydroxide ions or excess hydrogen ions keeping them from affecting the overall pH. This helps maintain the needed blood pH at about 7.4. Describe the buffering system that is used in human blood. Homework Article Review: “Universe as an Infant: Fatter Than Expected and Kind of Lumpy” by Dennis Overbye http://www.nytimes.com/2013/03/22/science/space/planck-satellite-shows-image-of-infant- universe.html?ref=space (note: the NY Times website may ask you to create an account to access the article) 10. What is the significance of the heat map image of the early cosmos? 11. What do you think the scientist mean by the statement: “the universe appears to be slightly lumpier”? 12. It seems every time we read an article scientist are always correcting old theories. Why should we bother to believe any of them, if they are going to change in the future? 13. What is the significance of the hot spots in the microwaves? 14. What do the scientists mean by the “dark matter”? 15. When examining the water molecule and its polarity, where is the slightly positive charge located, and where is the slightly negative charge located? 16. If you drop your drink on the floor during dinner, and place a paper towel over the spilled drink to clean it up, what process is occurring as you witness the paper towel pick up the drink? 17. Would you expect more temperature and weather fluctuations to occur in Oklahoma or New Jersey? Explain.
Transcript
www.njctl.org AP Biology Emergence of Organic Molecules
Emergence of Organic Molecules Early Earth and Early Universe Classwork
1. Briefly explain the biochemical experiment performed by Miller-Urey and its significance to the origin of living organisms.
2. The Earth is believed to be 4.5 billion years old. What evidence do scientists use to make this statement?
3. You are probably most familiar with the name Hubble from the Hubble telescope launched by NASA in 1990. What evidence did Edwin Hubble use to help support the Big Bang theory?
4. Where do scientist believe all the natural elements that make up the Earth originally came from?
5. Scientists have come up with the acronym LUCA. What do the letters stand for? Briefly describe the basis for this hypothesis.
6. Discuss the uniqueness of the chemical and physical properties of the water molecules, and the significance of these properties to life on Earth.
7. What sequence of events would occur in a lake as winter progresses, if solid water were more dense the liquid water, as is the case with most molecules?
8. Describe the two parts that make up a solution. 9. Living organisms use buffers to help maintain a steady pH in their internal environment.
Human blood has buffers. The buffer contains a large reservoir of an acid and a base. When something is added to the blood the buffer will either bind with excess hydroxide ions or excess hydrogen ions keeping them from affecting the overall pH. This helps maintain the needed blood pH at about 7.4. Describe the buffering system that is used in human blood.
Homework Article Review: “Universe as an Infant: Fatter Than Expected and Kind of Lumpy” by Dennis Overbye http://www.nytimes.com/2013/03/22/science/space/planck-satellite-shows-image-of-infant-universe.html?ref=space (note: the NY Times website may ask you to create an account to access the article)
10. What is the significance of the heat map image of the early cosmos? 11. What do you think the scientist mean by the statement: “the universe appears to be
slightly lumpier”? 12. It seems every time we read an article scientist are always correcting old theories. Why
should we bother to believe any of them, if they are going to change in the future? 13. What is the significance of the hot spots in the microwaves? 14. What do the scientists mean by the “dark matter”? 15. When examining the water molecule and its polarity, where is the slightly positive
charge located, and where is the slightly negative charge located? 16. If you drop your drink on the floor during dinner, and place a paper towel over the spilled
drink to clean it up, what process is occurring as you witness the paper towel pick up the drink?
17. Would you expect more temperature and weather fluctuations to occur in Oklahoma or New Jersey? Explain.
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Biological Molecules Classwork
18. Starches are called complex carbohydrates when speaking in terms of nutrition. What
kind of reaction must occur to break it down in to smaller components? Describe the reaction in detail.
19. Metabolism involves the building and breaking down of molecules in you body. Using molecular models, sketch two monosaccharides being joined together by dehydration synthesis. Be sure and circle where the H and OH came from on the monosaccharide.
20. If you had a polymer 15 monomers long how many water molecules would be needed to break the molecule down completely? Include a drawing and use arrows to indicate the point of breakage.
21. What evidence exists that supports the “organic monomers from space” theory? 22. From Stanley Miller’s experiment to create organic monomers from reactions, what 4
conditions had to be present on primitive earth to allow this to happen? 23. Polysaccharides can be use for storage and structure. Describe a plant and animal
storage and structural polysaccharide. 24. Sugar is a general term used in our world today. What is the biological definition of a
sugar? Explain the difference between monosaccharide and disaccharides. 25. Salad is excellent roughage for our digestive system. Although most people love the
taste, this biological molecule is indigestible by the humans. Cows on the other hand are herbivores whose entire diet tends to be grass. What kind of biological molecule found in plants can’t we digest? How are cows able to digest grass?
26. Write the equations used to make the 3 disaccharides sucrose, maltose and lactose. 27. If human DNA were stretch out, it would be over 6 feet long (2 meters) and is made of
over 3 billion base pairs. Although these facts seem daunting, if you look closely you will see that each base pair is part of a small repeating unit called a nucleotide. Describe a nucleotide and sketch for of them, each contains one of the bases found in DNA.
28. Compare and contrast DNA and RNA. Please include as much detail as possible in your answer.
29. Below is one stand of a DNA molecule. How did Chargaff findings contribute to what we know about base parings? Also sketch both sides of the molecules.
5’ ATTGCAG 3’ 30. DNA to RNA to Protein is the central dogma of molecular biology. As we have learned
proteins are major part of a living organisms cellular activities. Describe the four levels of protein structure in as much detail as you can.
31. The idea of protein synthesis happening outside the nucleus of the cell baffled scientist up until experiments using cell fractionation were able to isolate the source of protein synthesis. Describe the process of protein synthesis from DNA to protein assembly.
32. Biological molecules are often made of repeating units held together by unique bonds. Describe the reaction for amino acid being joined together to form polypeptides. Please include a sketch of two amino acids becoming a dipeptide.
33. Many scientists often refer the N terminus and the C-terminus. State what these refer to and sketch and label an amino acid showing both terminus ends.
34. Describe the main functions of lipids. Discuss the difference between saturated and unsaturated lipids.
35. Discuss carbohydrates, proteins and lipids with respect energy contained within each of them.
36. Omega-3 and Omega-6 oils are considered the so-called good fats. What is unique about the structure of “good” fats? What is a good dietary source of these fats?
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37. Fat, waxes, oils, and steroids all fall under the category of lipids. Two common lipids are phospholipids and triacylglycerol. Explain how their structure differs and how this affects the molecules when they come in contact with water.
Homework
38. How does hydrolysis participate in energy storage and metabolism? 39. When two carbohydrates are joined via dehydration synthesis, what is the link called that
joins them together? 40. What is it about today’s atmosphere in relation to primitive Earth’s atmosphere that
would be prohibitive to the formation of organic compounds? 41. What was Stanley Miller able to produce using inorganic molecules and high energy
input, and what was the significance of his experiment? 42. Humans do not possess the necessary enzymes to digest cellulose, however, it still aids
in digestion. How is this so? 43. Excess carbohydrates in our diet can be detrimental. What happens to excess glucose
in the human body? 44. A basketball player eats a sandwich before playing a game. At game time, what will
happen to the carbohydrates that were ingested? 45. List the two monosaccharides which form together to create the disaccharide Sucrose.
By what reaction does this occur? 46. What is the difference between a purine and a pyrimidine? Which bases are purines,
and which are pyrimidines? 47. What bonds link nucleotides together in nucleic acids? 48. When a protein denatures, what occurs? What causes a protein to denature? 49. What are the components of all amino acids, and which component determines the
unique nature of the amino acid? 50. What are the 7 types of proteins in organisms? 51. Considering the 4 levels of protein structure, what structure does hemoglobin have? Out
of the 7 types of proteins in organisms, which type is hemoglobin? 52. Describe what is meant when a lipid is described as amphiphilic. Give an example of
where we can find a lipid that displays this property. 53. When examining a phopholipid molecule, with the 2 fatty acid end, and the phosphate
end, which end is the polar end and which end is the non-polar end? 54. What is a steroid, and can you give an example with its function?
Development of Life Classwork
55. Scientist use fossil evidence to help determine when life first arrived on our planet. Describe how fossil can be formed.
56. When do scientist first believe life originated on our planet? And what role do stromatolites play in this puzzle?
57. The oldest eukaryotic organism is believed to be an endosymbiont. Provide a brief description how an endosymbiont can be formed. Also give an example.
58. LUCA is based on the idea that many organisms have similar common features. What features of life support LUCA?
59. Describe the minimum structural, metabolic and genetic components of a primitive cell. 60. How is Evolution different from the Origin of Life? 61. Discuss Oparin and coacervates.
Homework
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Article Review: “It’s Alive! It’s Alive! Maybe Right Here on Earth” by Dennis Overbye http://www.nytimes.com/2011/07/28/science/28life.html
62. What do most scientists agree is essential to describing life? 63. What is the significance of scientific research in the producing life form chemicals in a
test tube? 64. Describe the significance of Dr. Joyce’s test tube results. Are his results most like LUCA
or most like a form of life we have not yet discovered, why 65. Which theory of life would these findings support?
Article Review: The Origins of Life” by Helen Fields http://www.smithsonianmag.com/science-nature/The-Origins-of-Life.html
66. What kind of ecosystem can be found near the deep underwater ocean vents? 67. Describe Hazen's first experiments with the so-called pressure bomb. 68. Compare and contrast Hazen's Experiments with Stanley Miller’s Experiment. 69. What does Hazen mean when he uses the phrase “looking into the first step in that
courtship”? 70. Why does Hazen believe minerals play a part in the origin of life?
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Free Response
1. Complex molecules are crucial for life processes. How these molecules came to be on Earth is subject to ongoing speculation and research. Below are several fabricated or real pieces of evidence that may or may not support certain hypotheses regarding the creation of complex molecules on early Earth. Place each piece of evidence in the correct column in the table below. State whether the evidence is real or fabricated. Provide a justification for your decision based on current scientific thinking.
Evidence (fabricated or real)
a. The Earth was 30 million miles more distant from the sun in the early solar system.
b. The early atmosphere was oxygen rich. c. Complex organic molecules have been discovered in meteorites on the Earth. d. The early atmosphere contained simple molecules such as methane, carbon
dioxide, ammonia and water.
Evidence
Supports creation of complex molecules on early Earth
Does not support creation of complex molecules on early Earth
Evidence
Evidence
Justification
Justification
Evidence
Evidence
Justification
Justification
Evidence
Evidence
Justification
Justification
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2. The following diagram shows the Miller-Urey experimental setup.
a. Why did they select the
gases shown in the air mixture? b. Describe the conclusion
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4. Stromatolites (pictured below) are sedimentary rock that formed from layers of ancient bacteria, such as blue-green algae, and trapped sediments over many generations (millions to billions of years). Stromatolites are a microscopic version of the fossilization process that formed the fossils of the dinosaurs and other macroscopic organisms. Stromatolites are still forming and growing in places like Shark Bay, Australia.
a. If a scientist claims that life arose 6,000 years ago, 1 million years ago, or 100 million years ago, how can you use the geological and biological evidence shown below (stromatolites of Shark Bay, Australia) to evaluate or analyze that statement or hypothesis?
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5. A diagram depicting the alkaline hydrothermal vents hypothesis for origin of life on Earth is
shown below. a) Use the diagram to describe the hydrothermal vents hypothesis. b) Why is the hydrothermal vents hypothesis more supported by evidence that the
“water soup” suggested by the Miller-Urey experiment?
Sousa FL, Thiergart et. al.. 2013 Early bioenergetic evolution. Phil Trans R Soc B 368: 20130088
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Emergence of Organic Molecules-Answer Key
1. They created an artificial laboratory model of our ancient atmospheric gases along with
electric charges and water formation of the primitive components of organic molecules is possible. Organic molecules are found in all living organisms.
2. Scientist use radiometric dating to date very old material. The process compares a parent specimen’s radioactive elements quantity to a samples amount of radioactive elements quantity. Since radioactive elements break down at a known rate. This breakdown is called half-life. Scientists are able to use this ratio to calculate the age of the specimen.
3. Edwin Hubble used the red shift of the universe to support the Big Bang Theory. 4. All the elements on Earth were formed in reactions inside stars. 5. Last Universal Common Ancestor. The basis for this theory is that every living thing shares
characteristics, such as DNA, RNA, and ATP, that are statistically more likely to have arisen once in a single ancestor than to have evolved multiple times.
6. Water demonstrates cohesion, the hydrogen bonds keep water molecules close to one another. Plants rely on cohesion to bring water from roots up to leaves. Water has high specific heat. The H bonds break when heat is absorbed and form when heat is released. In nature it takes a tremendous amount of heat to raise the temperature by one degree Celsius. Bodies of water, such as lakes, rivers and oceans take a long time to heat, but once they do they hold onto that heat longer than the surrounding land. Climates and weather are direct result of the uneven heating patterns on the earth. Water has a High heat of vaporization, amount of heat needed to change liquid water to gaseous water. This helps with evaporative cooling, and maintains homeostasis in living organisms. Water the universal solvent; because of its polar nature it is able form bonds with other molecules. The positive side of the molecules and pull them apart forming ionic bonds. This disassociation forms aqueous solutions. Finally, water expands when it freezes. Because water is most dense at 4 degrees Celsius, allowing ice to float. Because ponds and lakes freeze from the bottom down, animals that overwinter have a safe place near the bottom of the aquatic environment.
7. The particles slow down enough to change from a liquid to a solid. If water was a typical compound any part of the liquid that froze would sink. Any living organism would have nowhere to go over the winter. They would risk getting hit by the dense frozen liquid as it sunk, they would also risk getting frozen themselves.
8. A solution consists of the solvent and the solute. The solvent dissolves the solute. 9. Carbonic acid is formed when carbon dioxide reacts with water in the blood plasma. The
carbonic acid than dissociates into bicarbonate and a hydrogen ion. As the blood pH shifts from an acidic or to a basic level the reaction will move in one direction or the other. For example if the pH in the blood begins to rise, more carbonic acid will dissociate providing more H ion, lowering the overall blood pH. If the blood pH lowers, H ions will be removed from the blood forming carbonic acid.
10. It showed the universe to be 80 to 100 million years older than previously thought. 11. The distribution of matter and energy throughout the universe is not consistent. 12. Opinion question 13. Hot spots in microwaves are submicroscopic quantum fluctuations which can produce
galaxies 14. Non-ordinary matter, it does not produce or absorb electromagnetic radiation 15. The two hydrogen atoms hold a slightly positive charge, while the oxygen atom holds a
slightly negative charge. 16. Capillary action due to adhesion. The water molecules are bonding with the fibers of the
paper towels and sticking there. Adhesion is defined as the attraction between a water molecule and a non-water molecule.
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17. This is a case where the specific heat capacity of water is considered. Due to the fact that water has such a high specific heat capacity, cities and states with water surrounding or bordering them have less dramatic changes in temperature and weather. Therefore, a state in the middle of the country like Oklahoma, with no large masses of water by it will experience more drastic changes in temperature, than a state like New Jersey on the coast of the Atlantic.
18. Starches are broken down into monosaccharides by hydrolysis. The reaction occurs when water interacts with the starch, breaking the covalent bonds in the starch and water. A hydrogen atom is attached to one saccharide, while a hydroxyl group is attached to the other.
19. A sketch similar to the one below.
20. 14 water molecules. Include a sketch 21. The dust in the solar system that created Earth was full of organic chemicals. Also,
meteorites found today that crashed into primitive Earth contain organic chemicals as well. 22. Absence of oxygen in the atmosphere as it would have broken down large organic
molecules. High Energy output in the form of the sun’s ultraviolet rays. Micromolecules found in the ocean and atmosphere. Time for the molecules to form and react.
23. Starch is an energy storage molecule found in plants; it can be a branched or unbranched polysaccharides. Glycogen is an energy storage molecule found in animals; it is always highly branched. Cellulose is a structural molecule found in plants; its bonds form chains, cross-linked by hydrogen bonds.
24. Sugars are carbohydrates that consist of the elements C, H, O in a 1:2:1 ratio. They end in the suffix -ose. Monosaccharides consist of a single monomer, C6H12O6. Disaccharides consist of two monomers.
25. Cellulose. Cows can digest this molecule because they have four stomach containing microbe which break down the fiber.
27. Nucleotides are composed of a phosphate, a sugar, and a nitrogenous base. Include a sketch.
28. DNA and RNA are both made up of nucleotides with a sugar, a phosphate, and a nitrogenous base. DNA has the sugar deoxyribose. RNA has the sugar ribose. DNA uses the bases thymine, guanine, cytosine, and adenine. RNA uses the bases uracil, guanine, cytosine, and adenine.
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29. Chargaff was able to isolate the bases in the DNA and show the percent of A’s is about the same as the percent of T’s, likewise C percentage is equal to G’s.
5’ ATTGCAG 3’ 3’ TAACGTC 5’
30. The primary level is the amino acid chain. The secondary level includes alpha helices and pleated sheets created by hydrogen bonding amongst amino acids. The tertiary structure is the overall 3D shape of the protein caused by hydrophobic interactions and disulfide bonds. Quaternary structure occurs when multiple peptide chains interact, forming a larger protein structure.
31. DNA is transcribed into RNA. The mRNA at the site of the ribosome codes for amino acids. The tRNA brings them to the A site and they are joined together by dehydration synthesis. The removal of water allows for a peptide bond to be formed.
32. Amino acids are joined through dehydration synthesis. Include a sketch 33. The C-Terminus is the carboxyl end of the amino acid and the N-Terminus in is the free
amino group end. Include a sketch 34. Lipids are energy storage molecules, components on the cell membrane, and involved in
metabolic activities as steroids. Unsaturated lipids have double and triple bonds. Saturated lipids have only single bonds.
35. Lipids are used for longterm energy storage. Carbohydrates provide energy in the short term. Proteins control the rate of metabolic reactions.
36. They contain carbon-to-carbon double bonds. Omega-3 fatty acids are polyunsaturated fats found naturally in oily fish, nuts, seeds, and leafy green vegetables.
37. Phospholipids are amphiphilic. In water, they create a bilayer with hydrophilic head facing the water and the hydrophobic tails accumulate inside the membrane. Triacylglycerol is hydrophobic.
38. In order to break the pryphosphate linkages in ATP and release the energy within, a hydrolysis reaction is necessary. ATP is broken down into ADP and an inorganic phosphate.
39. Glycosidic Link 40. Oxygen is present in today’s atmosphere, but was not present in early Earth’s atmosphere.
Due to oxygen’s ability to accept electrons, it would have broken down any organic molecules that were formed.
41. Stanley Miller was able to create amino acids and other organic molecules from inorganic molecules mirroring early Earth’s atmosphere. This lends credence to the theory that organic monomers were created on Earth via chemical reactions.
42. As cellulose passes through the digestive tract, it stimulates the digestive tract walls to secrete mucus which aids in digestion.
43. Excess glucose is converted to fat and stored in fatty tissue. Without exercise, this fat can accumulate in the body.
44. Carbohydrates provide quick, short lasting energy. They will be the first to be burned up by the player’s body.
45. Through dehydration synthesis, Glucose + Fructose yields Sucrose. 46. Purines (adenine and guanine) are 2-ringed structures. Pyrimidines (thymine, cytosine, and
uracil) are single-ringed structures. Purines form hydrogen bonds with pyrimidines in the “complimentary base pairing” that we see in DNA and RNA.
47. Phosphodiester bonds. 48. Denaturation occurs when a protein unfolds, and loses its functionality. Factors such as pH,
changes in temperature, and salinity can all cause a protein to denature. 49. All amino acids are composed of an amine group, a carboxyl group, and a side chain that is
unique to the amino acid. The side chain is what determines the amino acid’s properties. 50. Structural, contractile, storage, defense, transport, signaling, and enzymatic. 51. Hemoglobin is a transport protein with quaternary structure.
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52. Amphiphilic means that the molecule possesses a hydrophobic end and a hydrophilic end. Phospholipids are the most common example.
53. The phosphate end is the polar end and the fatty acid chains are the non-polar end. 54. A steroid is a lipid with a 4-ringed structure. They are essential for all life as they help
regulate reproduction, metabolism and other processes. Estrogen is a steroid produced by females which aids in preparing for reproduction by stimulating development of reproductive organs and growth of the uterus lining.
55. Fossil can be formed through pressure in sedimentary rock. They can also be formed form dead organisms in tree sap, tar pits, and when minerals replace bone.
56. Scientists believe life first existed 3.5 million years ago. Stromatolites are made when microscopic photosynthesizing cyanobacteria form microbial films that trap mud, sometimes trapping ancient cyanobacteria within the layers.
57. The endosymbiont is formed when smaller prokaryotic cells began living within larger cells. The most common example is the mitochondria and plastids that began living with in larger cells.
58. LUCA is supported by the universal features of genetic code, DNA/RNA polymerases, mRNA, tRNA, ribosomes, L-isomers of amino acids, lipid bilayers, Na+/K+ pumps, and ATP and ATP synthases.
59. To be considered a cell, the object in question must be enclosed in a phospholipid membrane and contain genetic information encoded in nucleic acids. It must be self-replicating. And metabolize energy using ATP as a storage molecule.
60. Evolution provides an explanation of the diversity of life. How organisms must adapt to selection pressures or the will die. The origin of life describes mechanisms that were able to produce molecules that could grow and replicate as long as an energy source is present.
61. Oparin was pretty sure life originated form coacervates. These microscopic spontaneously formed spherical aggregates of lipid molecules. He used these to show enzyme reactions worked better within these tiny membranes.
62. The ability to evolve and adapt 63. To discover how life originated 64. Dr. Joyce evolved a molecule that could replicate and evolve by itself. This may indicate that
life can arise spontaneously. 65. It would support Oparin’s theory that life arose from inorganic molecules 66. They are hot, high-pressure environments with rich mineral deposits inhabited by giant
worms, blind shrimp and sulfur-eating bacteria. 67. His first experiments were tiny capsules that were filled with pyruvate and carbon dioxide
and put in a chamber at 2000 atm and480 degree, the experiment yielded tens of thousands of organic molecules.
68. Miller’s experiments relied on gases of the early atmosphere and lightening to create organic molecules at the Earth’s surface. Hazen’s experiments used similar gases but at extreme pressure and temperatures that were at vents on ocean floor. Both produced organic molecules.
69. Hazen and his lab are looking in how the molecules that combined to form organic molecules actually ran into or came in contact with one another to react and form them.
70. Hazen explains there were only 50 or so minerals before life began, and with volcanoes and plate tectonics changing the earth leading to the creation of new minerals, new chemicals – some of them amino acids.
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1.
Evidence
Supports creation of complex molecules on early Earth
Does not support creation of complex molecules on early Earth
Evidence C
Evidence A
Justification This is true with prime examples being the Murchison meteorite and ALH84001, both of which contained complex organic molecules. From this information it can be hypothesized that complex molecules may have been brought from space in great amounts to the early earth. It is they that formed the basis of the first cells.
Justification The Earth has never been this far away from the sun and so the information is fabricated. This situation would have made it more difficult for complex molecules to arise as it is believed that high energy was required to cause the reactions necessary to make them. The proximity of the sun to the earth made high levels of radiation from the young sun available for these reactions. Increasing this distance by a third would have reduced the available energy
Evidence D
Evidence B
Justification Data suggests that this is correct and that complex molecules could have formed from these simple ones. Miller and Urey used this information for their experiment where they combined these chemicals in a flask, added an electrical spark and collected the resultant purines, prymidines and amino acids.
Justification This is not true as early atmosphere contained very low concentrations of oxygen. Levels rose only with the advent of photosynthetic organisms 2.4B years ago and then at a slow rate. Free oxygen in the atmosphere would have quickly oxidized any complex molecules making their life short and organization into cells highly improbable. Stability of these molecules over great spans of time was required for this process.
Essential knowledge 1.D.1: There are several hypotheses about the natural origin of life on Earth, each with supporting scientific evidence. LO 1.27 The student is able to describe a scientific hypothesis about the origin of life on Earth. [See SP 1.2] LO 1.31 The student is able to evaluate the accuracy and legitimacy of data to answer scientific questions about the origin of life on Earth. [See SP 4.4]
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2a. Water vapor, methane, hydrogen, carbon monoxide, and ammonia (the gas mixture) were chosen because the geological evidence implied that the early Earth’s atmosphere consisted of or had this particular gas mixture among others. 2b. The experiment showed that organic molecules such as amino acids, sugars, and larger hydrocarbons could be created from inorganic molecules that were present in the early atmosphere of Earth with the help of energetic or environmental conditions such as heat and lighting. Essential knowledge 1.D.1: There are several hypotheses about the natural origin of life on Earth, each with supporting scientific evidence. LO 1.27 The student is able to describe a scientific hypothesis about the origin of life on Earth. [See SP 1.2] LO 1.31 The student is able to evaluate the accuracy and legitimacy of data to answer scientific questions about the origin of life on Earth. [See SP 4.4] Essential knowledge 1.D.2: Scientific evidence from many different disciplines supports models of the origin of life. Learning Objective: LO 1.32 The student is able to justify the selection of geological, physical, and chemical data that reveal early Earth conditions. [See SP 4.1] 3a. Due to the presence of water there would be less chance of polymers forming because water would be added between the monomers and the polymers would be decomposed. 3b. All the monomers needed to create a cell would be made under the presence of water. Excess water drives the chemical equilibrium towards hydrolysis, and hydrolysis breaks up large molecules. Building larger molecules require the removal of water from monomers. Miller-Urey experiments stop at monomers and do not proceed towards larger molecules, because the chemical equilibrium prefers hydrolysis over dehydration synthesis. 3c. You can remove the water or decrease the amount of water in the experiment and check the effects of removing water from the experiment. Essential knowledge 1.D.1: There are several hypotheses about the natural origin of life on Earth, each with supporting scientific evidence. LO 1.28 The student is able to evaluate scientific questions based on hypotheses about the origin of life on Earth. [See SP 3.3] LO 1.29 The student is able to describe the reasons for revisions of scientific hypotheses of the origin of life on Earth. [See SP 6.3] LO 1.30 The student is able to evaluate scientific hypotheses about the origin of life on Earth. [See SP 6.5] 4. Stromatolites are widely distributed and ancient fossilized artifacts made by the sedimentary process of rock formation through the activity of microbes. Sediments were trapped by biofilms of ancient bacteria such as blue-green algae and over generations layers of biofilms were fossilized, creating the stromatolites. The process of stromatolite formation continues in the mounds of Shark Bay, Australia. If the time to create these mounds is extrapolated backwards in time, it can be concluded that the Earth is likely older than any of the times stated in the hypotheses.
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Essential knowledge 1.D.1: There are several hypotheses about the natural origin of life on Earth, each with supporting scientific evidence. LO 1.30 The student is able to evaluate scientific hypotheses about the origin of life on Earth. [See SP 6.5] LO 1.31 The student is able to evaluate the accuracy and legitimacy of data to answer scientific questions about the origin of life on Earth. [See SP 4.4] Essential knowledge 1.D.2: Scientific evidence from many different disciplines supports models of the origin of life. LO 1.32 The student is able to justify the selection of geological, physical, and chemical data that reveal early Earth conditions. [See SP 4.1] 5. a. RNA chemically evolve. RNA evolved an association with amino acids to produce proteins.
DNA evolved to assume the genetic responsibilities of RNA that led to the evolution of the first cells.
b. The geochemistry at the ocean and crust interface produces a basic and reducing environment (serpentinization). Important minerals involve in biochemistry such as Fe, Ni, S, and P are present under favorable redox states that allow for the reduction of carbon compounds producing amino acids, sugars, and nucleic bases in compartments defined by the crystalline structure of the Fe and Ni sulfide.
Essential knowledge 1.D.1: There are several hypotheses about the natural origin of life on Earth, each with supporting scientific evidence. LO 1.30 The student is able to evaluate scientific hypotheses about the origin of life on Earth. [See SP 6.5] LO 1.31 The student is able to evaluate the accuracy and legitimacy of data to answer scientific questions about the origin of life on Earth. [See SP 4.4] Essential knowledge 1.D.2: Scientific evidence from many different disciplines supports models of the origin of life. LO 1.32 The student is able to justify the selection of geological, physical, and chemical data that reveal early Earth conditions. [See SP 4.1]
