Free Response Slide 2 / 82 1 Complex molecules are crucial for - - PDF document

Free Response

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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.

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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 that the results of the experiment

support?

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3 Hydrolysis, or the addition of water in between monomers, breaks up large molecules. Dehydration synthesis is the reverse chemical reaction.

A

With reference to the diagram in question 2, would you expect to find large molecules (many linked monomers) in the cooled water section of the apparatus? Explain.

B

Do you think it is possible to create a cell under the physical and chemical conditions used in the Miller-Urey experiment? Explain.

C

With reference to the diagram in question 2, how can you reduce the possibility of hydrolysis occurring in the experiment?

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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

• ver 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?

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This material is made freely available at www.njctl.org and is intended for the non-commercial use of students and teachers. These materials may not be used for any commercial purpose without the written permission of the owners. NJCTL maintains its website for the convenience of teachers who wish to make their work available to other teachers, participate in a virtual professional learning community, and/or provide access to course materials to parents, students and others.

Click to go to website: www.njctl.org New Jersey Center for Teaching and Learning Progressive Science Initiative

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www.njctl.org

Emergence of Organic Molecules Practice Questions

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1 Briefly explain the biochemical experiment performed by Miller-Urey and its significance to the origin of living organisms.

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2 The Earth is believed to be 4.5 billion years old. What evidence do scientists use to make this statement?

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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?

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Article Review: “Universe as an Infant: Fatter Than Expected and Kind of Lumpy” by Dennis Overbye

http://www.nytimes.com/2013/03/22/science/spac e/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)

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4 Where do scientist believe all the natural elements that make up the Earth originally came from?

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5 Scientists have come up with the acronym LUCA. What do the letters stand for? Briefly describe the basis for this hypothesis.

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6 Discuss the uniqueness of the chemical and physical properties of the water molecules, and the significance of these properties to life on Earth.

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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?

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8 Describe the two parts that make up a solution.

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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.

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10 What is the significance of the heat map image of the early cosmos?

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11 What do you think the scientist mean by the statement: “the universe appears to be slightly lumpier”?

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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?

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13 What is the significance of the hot spots in the microwaves?

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14 What do the scientists mean by the “dark matter”?

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15 When examining the water molecule and its polarity, where is the slightly positive charge located, and where is the slightly negative charge located?

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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?

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17 Would you expect more temperature and weather fluctuations to occur in Oklahoma or New Jersey? Explain.

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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.

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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.

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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.

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21 What evidence exists that supports the “organic monomers from space” theory?

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22 From Stanley Miller’s experiment to create

• rganic monomers from reactions, what 4

conditions had to be present on primitive earth to allow this to happen?

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23 Polysaccharides can be use for storage and

• structure. Describe a plant and animal storage

and structural polysaccharide.

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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.

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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?

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26 Write the equations used to make the 3 disaccharides sucrose, maltose and lactose.

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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
• f them, each contains one of the bases found in

DNA.

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28 Compare and contrast DNA and RNA. Please include as much detail as possible in your answer.

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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’

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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.

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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.

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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.

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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.

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34 Describe the main functions of lipids. Discuss the difference between saturated and unsaturated lipids.

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35 Discuss carbohydrates, proteins and lipids with respect energy contained within each of them.

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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.

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38 How does hydrolysis participate in energy storage and metabolism?

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39 When two carbohydrates are joined via dehydration synthesis, what is the link called that joins them together?

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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?

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41 What was Stanley Miller able to produce using inorganic molecules and high energy input, and what was the significance of his experiment?

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42 Humans do not possess the necessary enzymes to digest cellulose, however, it still aids in

• digestion. How is this so?

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43 Excess carbohydrates in our diet can be

• detrimental. What happens to excess glucose in

the human body?

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44 A basketball player eats a sandwich before playing a game. At game time, what will happen to the carbohydrates that were ingested?

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45 List the two monosaccharides which form together to create the disaccharide Sucrose. By what reaction does this occur?

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46 What is the difference between a purine and a pyrimidine? Which bases are purines, and which are pyrimidines?

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47 What bonds link nucleotides together in nucleic acids?

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48 When a protein denatures, what occurs? What causes a protein to denature?

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49 What are the components of all amino acids, and which component determines the unique nature

• f the amino acid?

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50 What are the 7 types of proteins in organisms?

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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?

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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.

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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?

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54 What is a steroid, and can you give an example with its function?

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55 Scientist use fossil evidence to help determine when life first arrived on our planet. Describe how fossil can be formed.

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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

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56 When do scientist first believe life originated on

• ur planet? And what role do stromatolites play in

this puzzle?

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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.

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58 LUCA is based on the idea that many organisms have similar common features. What features of life support LUCA?

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59 Describe the minimum structural, metabolic and genetic components of a primitive cell.

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Article Review: The Origins of Life” by Helen Fields

http://www.smithsonianmag.com/science- nature/The-Origins-of-Life.html

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60 How is Evolution different from the Origin of Life?

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61 Discuss Oparin and coacervates.

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62 What do most scientists agree is essential to describing life?

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63 What is the significance of scientific research in the producing life form chemicals in a test tube?

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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

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65 Which theory of life would these findings support?

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66 What kind of ecosystem can be found near the deep underwater ocean vents?

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67 Describe Hazen's first experiments with the so- called pressure bomb.

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68 Compare and contrast Hazen's Experiments with Stanley Miller’s Experiment.

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69 What does Hazen mean when he uses the phrase “looking into the first step in that courtship”?

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70 Why does Hazen believe minerals play a part in the origin of life?

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