Study Island - Ms. Doran's Biology Class - Home



Study IslandCopyright ? 2014 Edmentum - All rights reserved. Generation Date: 09/04/2014 Generated By: Kurt Ritter Organic Molecules & Water1. Cellular processes are carried out by many different types of molecules, mostly proteins. The function of each protein molecule depends on its shape which, in turn, is determined by the protein's specific sequence of?_______. A.amino acidsB.triglyceridesC.nucleotidesD.monosaccharidesEnzymes2. An enzyme is a biomolecule that increases the rate of a chemical reaction. An enzyme is a kind of?_______. A.catalystB.inhibitorC.translatorD.ribosomeEnzymes3. When cellular respiration occurs within a cell, carbon dioxide is formed as a waste product. The carbon dioxide is transported out of the cell and absorbed by the blood stream. There, the carbon dioxide undergoes a chemical reaction and forms carbonic acid within the blood.When the carbonic acid reaches the capillaries in the lungs, the enzyme carbonic anhydrase helps reverse the reaction, and the carbonic acid is converted back to carbon dioxide and water.Which of the following would most likely happen if a person's body stopped producing carbonic anhydrase? A.The blood's volume would increase until a hemorrhage occurred.B.The person would begin exhaling carbonic acid instead of carbon dioxideC.The person's breathing rate would slow down.D.The blood's acidity would increase and become toxic.Enzymes4. All cells in multicellular organisms contain thousands of different kinds of enzymes that are specialized to catalyze different chemical reactions. Given this information, which of the following is most likely to be true? A.All cells contain exactly the same number of enzymes.B.All cells do not contain the same types of enzymes.C.All cells do not contain enzymes.D.All cells contain exactly the same types of anic Molecules & Water5. Suppose that the temperature in the ecosystem below dips below freezing.What would happen to the fish swimming in the lake? A.The fish would move more rapidly to increase their body temperature.B.Ice would only form on the bottom of the lake, so the fish would be okay.C.The fish would die because the lake would freeze solid.D.Ice would form on the surface of the lake and insulate the anic Molecules & Water6. Nucleic acids, proteins, and other large biological molecules are known as polymers because A.they are the base units used in the formation of plastics.B.they all contain only ionic bonds.C.they contain many small, repeating subunits bonded together.D.they all have the capability of functioning as enzymes.Enzymes7. Hydrogen peroxide is a substance that is produced as a byproduct of many cell processes. However, hydrogen peroxide is toxic to cells. In fact, if cells are unable to break down hydrogen peroxide, they become poisoned and die.The chemical reaction for the breakdown of hydrogen peroxide is shown below.What role does catalase play in this reaction? A.Catalase in an enzyme that slows down the reaction.B.Catalase is a product that is created during the reaction.C.Catalase is an enzyme that speeds up the reaction.D.Catalase is a reactant that gets used up in the reaction.Enzymes8. Which of the following enzymes serve as catalysts in metabolism?I.amylaseII.lactaseIII.pepsinIV.polymeraseA.I, II, and III onlyB.IV onlyC.I, II, III, and IVD.I and II onlyOrganic Molecules & Water9. Technology Enhanced Questions are not available in Word format. Enzymes10. Any factor that changes the shape of an enzyme can affect the enzyme's activity. Which of the following two factors affect an enzyme's operation the most? A.amount of light and pressureB.blood glucose level and pHC.temperature and pHD.amount of light and temperatureEnzymes11. Examine the diagram below.If the black line represents a reaction without an enzyme and the red line represents the same reaction with the addition of an enzyme, what can be said of the relationship between the use of an enzyme and the energy of the reaction? A.Less energy is released by a reaction with an enzyme.B.More energy is absorbed by reactions without an enzyme.C.More energy is absorbed by a reaction with an enzyme.D.Less energy is released by a reaction without an enzyme.Enzymes12. Homeostasis is the ability of an organism to maintain a relatively stable internal environment. How would an organism's homeostasis be affected if it was not able to produce enzymes? A.Without enzymes, chemical reactions would not occur quickly enough to sustain life.B.Without enzymes, the temperature inside cells would increase rapidly.C.Without enzymes, biochemical reactions would cease completely.D.Without enzymes, ribosomes would break down proteins, rather than build anic Molecules & Water13. A large carbohydrate molecule is composed of several subunits, such as glucose. An example of a large carbohydrate molecule is?_______. A.celluloseB.starchC.glycogenD.all of theseOrganic Molecules & Water14. Which of the following are examples of nucleic acids? A.collagen and keratinB.DNA and RNAC.glucose and starchD.saturated fats and unsaturated fatsOrganic Molecules & Water15. Protein molecules are composed of long chains of?_______. A.amino acidsB.DNAC.ribosomesD.RNAOrganic Molecules & Water16. Water is important to plant cells because it is used as one of the reactants in the process of photosynthesis. What is another reason why water is important to plant cells? A.Water can be used as a substitute for glucose in times of distress.B.Water is a major structural component found in plant cell walls.C.Water helps to maintain turgidity in plant cells.D.Water signals plant DNA to start transcription and translation.Enzymes17. The graph below shows the relationship between pH and three different digestive enzymes.Pepsin is found in the stomach. Salivary amylase is found in the mouth. And arginase is found in the liver. What does the graph indicate about the relative acidity of these three locations? A.The stomach is more acidic than the liver, which is more acidic than the mouth.B.The mouth is more acidic than the stomach, which is more acidic than the liver.C.The stomach is more acidic than the mouth, which is more acidic than the liver.D.The liver is more acidic than the mouth, which is more acidic than the stomach.Enzymes18. The above graph shows how temperature affects the rate of a reaction that uses the catalase enzyme. What trend is shown by the graph? A.Between zero and twenty-seven degrees Celsius, the rate of the reaction increases as the temperature increases.B.Between sixty and one hundred degrees Celsius, the rate of the reaction decreases as the temperature increases.C.Between zero and twenty-seven degrees Celsius, the rate of the reaction decreases as the temperature increases.D.Between thirty-seven and sixty degrees Celsius, the rate of the reaction increases as the temperature increases.Enzymes19. Siamese cats are characterized by light and dark regions of fur.The darker parts occur on the cooler parts of the cat's body because the enzyme that catalyzes the formation of the dark pigment is more active when cool. This example shows that enzymes are affected by?????????????. A.concentrationB.temperatureC.pHD.all of theseEnzymes20. Examine the diagram of the enzyme catalase below:How does the structure of this enzyme help with its function? A.The enzyme's substrate is a mirror image of the enzyme, thus allowing it to reverse any reactions initiated by the enzyme.B.The enzyme's active site can change shape in order to match any substrates in need of a catalyst.C.The enzyme's shape fits its substrate's shape, thus allowing the enzyme to catalyze the appropriate reaction.D.The enzyme is much larger than its substrate, thus allowing the catalyzed chemical reaction to take place inside the enzyme.Enzymes21. Each enzyme produced by the body is A.incomplete—meaning it requires other parts before it is able to bind to a molecule.B.specific—meaning it is only able to catalyze a reaction with a certain molecule.C.open—meaning it is able to catalyze a reaction with any molecule.D.immature—meaning it cannot catalyze a reaction until many years anic Molecules & Water22. Nucleic acids are one of the four major macromolecules.The main functions of nucleic acids are to A.store and transport energy and structural components in the cell.B.aid in development, the immune system, and blood clotting.C.carry genetic material and create structures inside the cell.D.act as enzymes, cell signals, and structural support for the anic Molecules & Water23. Nitrogen atoms are part of the structure of some organic molecules, such as all amino acids and some modified carbohydrates. What other organic molecules contain nitrogen? A.nucleotidesB.fatty acidsC.celluloseD.starchOrganic Molecules & Water24. Water is the most abundant molecule found in living organisms. Most mammals, in fact, are approximately 70% water by weight. About two-thirds of this water is present inside cells. The other one-third is present outside cells (e.g., in blood plasma or other body fluids). Why is water so important to cells? A.Water determines which proteins are translated from the cellular DNA.B.Water is stored in the cells to be used when the organism gets thirsty.C.The main structural component found in plasma membranes and cell walls is water.D.Almost all the chemical reactions in life processes occur in solutions with water.Enzymes25. Which of the following describes the role that enzymes play in the process of metabolism? A.Enzymes store the chemical energy that is used to construct nucleic acids during metabolism.B.Enzymes increase the rate of the chemical reactions carried out during metabolism.C.Enzymes provide the chemical energy that is broken down and released during metabolism.D.Enzymes carry the genetic instructions required for a cell to initiate anic Molecules & Water26. Atoms of what element form the backbone of large, complex molecules such as sugars and fats? A.oxygenB.sodiumC.sulfurD.carbonEnzymes27. Examine the following chemical reaction, which is catalyzed by the enzyme catalase:What molecule is catalase breaking down in this reaction? A.O2B.There are no molecules in this reaction.C.H2OD.H2O2Enzymes28. Catalase is an enzyme that is found in all living tissues. Cells need catalase in order to function properly.Which of the following statements can be inferred using the above information? A.Cells can function equally as well at all temperatures because enzymes are effective at all temperatures.B.Cells only function within a specific temperature range because enzymes only function within a specific temperature range.C.Cells only function within a specific pH range because enzymes only function within a specific pH range.D.Cells can function equally as well at all pH's because enzymes are effective at all pH'anic Molecules & Water29. What role do ATP and NADH play in living cells? A.They also store and transfer information.B.They provide structural support to cell membranes.C.They are involved in cell-to-cell signaling.D.They store and transfer energy.Enzymes30. The graph below shows the relationship between pH and three different digestive enzymes.Which of the following conclusions can be drawn from this graph? A.Enzymes are only able to operate in acidic environments.B.Digestive enzymes are most active in an environment with a pH of 7.C.Each enzyme operates best within a certain pH range.D.Enzymes operate most efficiently within a certain range of temperatures.Enzymes31. The graph below shows the relationship between pH and three different digestive enzymes.Pepsin is produced by cells lining the stomach. It catalyzes reactions needed to digest certain proteins. After leaving the stomach, food enters the small intestine. The pH of the small intestine is around 7.What would most likely happen to pepsin enzymes that traveled with the food from the stomach to the small intestines? A.The pepsin would begin to digest carbohydratesB.The pepsin would turn into the enzyme arginase.C.The pepsin would continue to digest proteins in the small intestine.D.The pepsin would become anic Molecules & Water32. A student is given a small amount of unknown tan-colored liquid substance. This unknown liquid is placed into a glass of water and mixed. Despite mixing, the tan liquid remains separated from the water and collects as a large droplet at the top. Which of the macromolecule groups is this liquid MOST likely to be a member of? A.carbohydratesB.proteinsC.lipidsD.nucleic acidsEnzymes33. Enzymes are catalysts. This means that they are able to speed up chemical reactions. Which of the following statements is also true of enzyme catalysts? A.They increase the energy that must be absorbed by reactions.B.They increase the energy that is released by reactions.C.They are not used up by reactions.D.They must be continuously replaced after each catalyzed anic Molecules & Water34. A?_______?is a kind of lipid that can store energy for a long period of time. These lipids are made up of long chains of carbon and oxygen atoms bonded to a backbone structure. A.carbohydrateB.fatC.proteinD.nucleic acidOrganic Molecules & Water35. Examine the diagram of the enzyme below:How does the structure of this enzyme help with its function? A.The enzyme's shape complements the substrate's shape, so it only catalyzes specific reactions.B.Since the enzyme's shape matches the substrate's shape, it catalyzes only reverse reactions.C.Since the enzyme is larger than the substrate, catalytic reactions can occur within the enzyme itself.D.The enzyme's active site is amorphous and can change its shape to fit any substrate.Enzymes36. Suppose that enzyme X catalyzes a reaction that involves the breakdown of a molecule. The product of this reaction is an amino acid. What molecule is the enzyme breaking down? A.a proteinB.a carbohydrateC.a mineralD.a lipidEnzymes37. In order for cells to function properly, the enzymes that they contain must also function properly. What can be inferred using the above information? A.Cells function best at low pH's.B.Cells can function equally as well at all pH's.C.Cells function best at high pH's.D.Cells do not function well at pH's that are too high or too low.Enzymes38. Which of the following can affect the function of a cell? A.high acidityB.low temperatureC.high temperatureD.all of theseOrganic Molecules & Water39. Carbohydrates are composed of which three elements? A.oxygen, hydrogen, and nitrogenB.carbon, nitrogen, and phosphorusC.oxygen, sulfur, and phosphorusD.carbon, hydrogen, and oxygenOrganic Molecules & Water40. DNA molecules store genetic information and allow for self-replicating life. Molecules of DNA can be long and very complex. They always consist of smaller molecules that are made up of nitrogenous bases, phosphate groups, and 5-carbon sugars.DNA is an example of a complex?_______. anic moleculeB.carbohydrate polymerC.protein structureD.inorganic moleculeEnzymes41. A biochemist is attempting to replicate a chemical reaction that commonly takes place in cells. During the chemical reaction, starch is broken down into glucose. What will most likely happen if the biochemist adds an enzyme to the reactants? A.The reaction will speed up.B.The reaction will slow down.C.The reaction will take place at a higher temperature.D.The reaction will stop.Enzymes42. Lactase is an enzyme that breaks down the complex carbohydrate lactose into glucose and galactose, which can be absorbed by the bloodstream and carried to the body's cells. Lactose is found primarily in dairy products.What would most likely happen to a person who had a shortage of lactase? A.The person's pancreas would not be able to regulate the body's blood glucose level.B.The person would be unable to fully digest dairy products.C.The person would develop an allergy for dairy products.D.The person would not be able to digest any carbohydrates.Enzymes43. An enzyme is a biomolecule that increases the rate of a chemical reaction. Which of the following is true about enzymes?I.Enzymes are not consumed during a chemical reaction.II.Enzymes are specific to particular molecules.III.Enzymes increase the energy produced by a chemical reaction.A.I and II onlyB.I and III onlyC.II onlyD.I, II, and IIIOrganic Molecules & Water44. All living organisms contain carbon atoms. Which of the following is an important characteristic of carbon? A.Carbon atoms are highly reactive and form unstable bonds with any available atom.B.Carbon atoms can bond with many other kinds of atoms to form very stable molecules.C.Carbon atoms are very stable and do not easily form bonds with other atoms.D.Carbon atoms can bond with any other atom, but they cannot form bonds with other carbon atoms.Enzymes45. The above graph shows how temperature affects the rate of a reaction that uses the catalase enzyme. At what temperatures, approximately, is the enzyme the most effective? A.between 27°C and 37°CB.between 0°C and 27°CC.between 37°C and 60°CD.between 60°C and 100°COrganic Molecules & Water46. Which of the following best describes a carbohydrate? A.Carbohydrates are composed of amino acid monomers and are involved in cell signaling, cell transport, immune responses, and the cell cycle.B.Carbohydrates are organic macromolecules that are insoluble in water and have the ability to store energy for extended periods of time.C.Carbohydrates always consist of a five-carbon sugar, a nitrogenous base, and one or more phosphate groups and are used to store genetic information.D.Carbohydrates are organic macromolecules that are made up of carbon, hydrogen, and oxygen atoms and are used for energy storage or as structural anic Molecules & Water47. Carbon atoms have four electrons in their outer shell. This means that a single carbon atom can form up to?_______?bonds with other atoms. A.sixB.fourC.eightD.twoOrganic Molecules & Water48. Carbohydrates, such as glucose, are excellent sources of immediate energy for living organisms. More complex carbohydrates, such as glycogen and starch, can also be used for the long term storage of energy. However, carbohydrates play other vital roles, too. Which of the following describes another common use for carbohydrates? A.Cellulose is used as a structural component in plant cell walls.B.Enzymes help speed up metabolic reactions.C.Keratin provides support in hair, nails, feathers, hooves, and some animal shells.D.Collagen is a major component in cartilage and tendons.Enzymes49. Tobin perfomed an experiment in which he mixed varying amounts of enzyme with an excess amount of a certain molecule. He measured the rate of each reaction and recorded his data in the table below.Enzyme Concentration(millimoles)Reaction Rate(micromoles/minute)001000.052000.103000.154000.205000.25What can Tobin conclude about the relationship between the enzyme concentration and the reaction rate in the presence of excess molecules? A.There is no relationship between the enzyme concentration and the reaction rate.B.There is an inverse relationship; as the enzyme concentration increases, the reaction rate decreases.C.The experiment is invalid because it was performed in the presence of excess molecules.D.There is a direct relationship; as the enzyme concentration increases, the rate of reaction increases.Enzymes50. The graph below shows the reaction rates of four different chemical reactions.A reaction that is catalyzed by an enzyme usually absorbs less energy and is faster than normal reactions.Which of the reactions was most likely catalyzed by an enzyme? A.Reaction CB.Reaction DC.Reaction AD.Reaction BOrganic Molecules & Water51. In most animal cells, a complex network of proteins provides which of the following? anizationB.movementC.shapeD.all of theseOrganic Molecules & Water52. Which of the following is true about protein molecules? A.Protein molecules have many functions in the body, including the storage of genetic information.B.The shape and folded structure of a protein molecule are important in determining its function.C.Protein molecules are made up of strands of DNA joined together by amino acid sequences.D.The sequence of amino acids that make up a protein molecule do not affect its function.Enzymes53. Hydrogen peroxide is a substance that is produced as a byproduct of many cell processes. However, hydrogen peroxide is toxic to cells. In fact, if cells are unable to break down hydrogen peroxide, they become poisoned and die.Catalase is an enzyme that is found in all living tissues. This enzyme speeds up the reaction that breaks down hydrogen peroxide into less harmful substances.What substances are formed as a result of this reaction? A.hydrogen peroxide and waterB.hydrogen peroxide and oxygenC.water and ozoneD.water and oxygenOrganic Molecules & Water54. Which of the following is true about nucleic acids?I.Nucleic acids always consist of a five-carbon sugar, a nitrogenous base, and one or more phosphate groups.II.Both DNA, which stores genetic information and encodes protein sequences, and RNA, which is involved in the direct production of proteins, are nucleic acids.III.Nucleic acids are usually insoluble in water and are used for long term energy storage.IV.Glucose, cellulose, and starch are examples of nucleic acids found in most cells.A.I and II onlyB.I, III, and IV onlyC.II onlyD.I, II, III, and IVEnzymes55. The diagram below represents an enzyme-substrate complex.To which of the following could this complex best be compared? A.dime and pennyB.lock and keyC.salt and pepperD.shoe and sockOrganic Molecules & Water56. Nucleic acids are biological polymers that are comprised of nucleotide monomers covalently bonded together.The picture above shows two monomer units of a nucleic acid chain. What are the components that make up each nucleotide monomer? A.a five-carbon sugar, a phosphate group, and an amino acidB.glucose, a phosphate group, and a nitrogenous baseC.glucose, a phophate group, and an amino acidD.a five-carbon sugar, a phosphate group, and a nitrogenous baseOrganic Molecules & Water57. In which of the following are lipids found? A.in saturated and unsaturated fatsB.in biological membranesC.in some vitamins and steroidsD.all of theseOrganic Molecules & Water58. Organic macromolecules called?_______?are insoluble in water, are often found in biological membranes and other waterproof coverings, and have the ability to store energy for extended periods of time. A.lipidsB.carbohydratesC.nucleic acidsD.proteinsOrganic Molecules & Water59. Technology Enhanced Questions are not available in Word format. Organic Molecules & Water60. Sugars such as glucose, fructose, and ribose are examples of?_______. A.nucleic acidsB.proteinsC.lipidsD.carbohydratesAnswers1. A 2. A 3. D 4. B 5. D 6. C 7. C 8. A 9. -- 10. C 11. B 12. A 13. D 14. B 15. A 16. C 17. C 18. A 19. B 20. C 21. B 22. C 23. A 24. D 25. B 26. D 27. D 28. B 29. D 30. C 31. D 32. C 33. C 34. B 35. A 36. A 37. D 38. D 39. D 40. A 41. A 42. B 43. A 44. B 45. A 46. D 47. B 48. A 49. D 50. D 51. D 52. B 53. D 54. A 55. B 56. D 57. D 58. A 59. -- 60. D Explanations1. Amino acids are the monomers of proteins. The function of a protein depends on its shape which is determined by the protein's specific sequence of amino acids. These sequences of amino acids are, in turn, coded by the sequences of nucleotides in the organism's DNA.2. Catalysts accelerate the rate of a chemical reaction. Chemical reactions that occur in living systems can be catalyzed by protein molecules called enzymes, which are a type of catalyst.3. Without carbonic anhydrase, the reaction that causes carbonic acid to become carbon dioxide and water would not take place quickly enough for the person to exhale enough carbon dioxide. The carbon dioxide, in the form of carbonic acid, would build up in the bloodstream, causing the blood pH to rapidly decrease to toxic levels.4. In multicellular organisms, cells are specialized to perform specific functions in different areas of the body. Since cells perform different functions, they require different enzymes. Thus, all cells do not contain the same types of enzymes.5. Most solids are more dense than their liquid forms. Ice, however, is unique in that it is less dense than liquid water and is able to float on surfaces of bodies of water, such as lakes and oceans.When ice forms on the surfaces of lakes and oceans, it serves as a layer of insulation. This prevents the water bodies from freezing solid and also protects organisms, such as fish, that live within them.6. Nucleic acids, proteins, and other large biological molecules are known as polymers because they contain many small, repeating subunits bonded together.For example, proteins contain many amino acid monomers covalently bonded together, and nucleic acids contain many nucleotide monomers covalently bonded together.7. Catalase is an enzyme that is found in all living tissues. This enzyme speeds up the reaction that breaks down hydrogen peroxide into water and oxygen.8. Amylase, lactase, and pepsin play important roles in catalyzing the reactions that occur during metabolism. Amylase is an enzyme that aids in the digestion of carbohydrates. It is present in the saliva and pancreas of humans and catalyzes the breakdown of starches into smaller carbohydrates. Lactase is an enzyme that is found primarily in the small intestine, liver, and kidney. Lactase catalyzes the breakdown of lactose into simple sugars, such as glucose. Pepsin is an enzyme that aids in the digestion of proteins, such as those found in meat and eggs. Pepsin is primarily found in the gastric juice of the stomach. Only I, II, and III serve as catalysts in metabolism.Polymerase is an enzyme that plays an important role in the polymerization of new DNA and RNA molecules during DNA replication and transcription.9. --10. Most enzymes are only active within certain temperature and pH ranges.11. Many chemical reactions need energy to get them started. This energy is known as the activation energy. Enzymes help catalyze, or speed up, these chemical reactions by lowering the amount of activation energy needed for the reactions to proceed. Reactions that do not use an enzyme require more energy.12. Most chemical reactions occur very slowly at low temperatures, including the temperatures found inside the bodies of most animals. Without enzymes, most of the vital chemical reactions that take place inside cells would occur so slowly that the organism would die before the necessary products were achieved. Enzymes allow the reactions to speed up to the rate necessary to keep the organism alive.13. Polysaccharides, or large carbohydrate molecules, are polymers that are made up of monosaccharide subunits. Starch, cellulose, and glycogen are all examples of large carbohydrate molecules. Starch, cellulose, and glycogen are all composed of glucose subunits linked in different ways. Starches have branched chains of glucose subunits and are used as food storage for plants. Glycogen has more highly branched chains of glucose than starch and is used by animals instead of plants. Cellulose is a mostly straight chain of glucose subunits and is used to form the cell wall of plants.14. There are two main types of nucleic acids - ribonucleic acids (RNA) and deoxyribonucleic acids (DNA). These nucleic acids are different because their five-carbon sugars are different. RNA contains ribose, and DNA contains deoxyribose. DNA and RNA also have different functions. DNA stores genetic information and encodes the sequences of all the cell's proteins whereas RNA is involved in the direct production of the proteins.15. There are over 20 different kinds of amino acids, which, when connected in long chains, form protein molecules.These long chains are usually folded into specific conformations. The sequence of amino acids and the shape of the chain are a result of attractions between the chain's parts.16. Plant cells must retain their turgidity, or rigid structure, in order to effectively undergo photosynthesis, because if a plant's stems or leaves wilt, the surfaces of the leaves will not be able to properly absorb energy from the Sun.Inside of plant cells are large vacuoles that hold water. These vacuoles can take up 30-90% of the total volume of the plant cell. The water in these vacuoles helps to maintain turgidity in the plant cells.17. Enzymes are well-adapted to function optimally in the places where they are found in the body. Knowing this, you can ascertain from the graph that the stomach has an average pH of 2, the mouth has an average pH of 7, and the liver has an average pH of 9.5.18. In general, between zero and twenty-seven degrees Celsius, the rate of the reaction increases as the temperature increases. Then, between thirty-seven and sixty degrees Celsius, the rate of the reaction decreases as the temperature increases. Finally, between sixty and one hundred degrees Celsius, no reaction occurs; the rate of the reaction equals 0?ml/s. At these temperatures, the enzyme is denatured.19. Although enzymes are also affected by the pH and the concentration of the enzyme and substrate in their environment, this specific example shows that enzymes are affected by temperature.20. The shape of an enzyme determines how it works. Most enzymes have a surface with one or more deep folds. The folds make pockets, which are called active sites.The active sites match folds in the substrate's surface. Once an enzyme binds to a substrate, the amount of energy needed to start a chemical reaction with the substrate is reduced.21. Enzymes are specific; they fit certain molecules like a key fits a lock. This allows the enzyme to bind to the molecule and catalyze its reaction.22. The main functions of nucleic acids are to carry genetic material and create structures inside the cell.A nucleic acid is a macromolecule that is made up of chains of nucleotides. The two main types of nucleic acids are DNA and RNA.23. All nucleotides are made up of three component compounds:a 5-carbon sugar (ribose or deoxyribose),a phosphate group, anda nitrogenous base.The nitrogenous bases are a group of compounds with a complex one- or two-ring structure made up of carbon and nitrogen atoms in single and double bond combinations.24. Water is an extremely important molecule to cells because almost all the chemical reactions in life processes occur in solutions with water. Without water, processes such as photosynthesis and cellular respiration, or even simpler processes such as diffusion and osmosis, could not occur. Also, cells would be unable to manufacture and transport ATP to provide energy for the organism. Water is an essential molecule to all living things.25. Enzymes increase the rate of the chemical reactions carried out during metabolism by lowering the activation energy necessary to initiate these reactions. Without enzymes catalyzing the chemical reactions that are performed during metabolism, cells would not be able to perform metabolism quickly enough to support life.26. The ability for carbon to bond to multiple other carbon atoms to form long carbon backbones facilitates the formation of chain-shaped or ring-shaped molecules, such as fats and sugars.27. In the given reaction, hydrogen peroxide (H2O2) was broken down into water and oxygen in the presence of catalase.28. The graph shows that catalase only functions within a specific temperature range. If the temperature is too high, catalase changes its shape and is no longer effective. Since catalase plays an important role in all cells, cells can only function within a specific temperature range.Although it is also true that cells can only function within a specific pH range, this fact cannot be inferred from the given information.29. ATP is a monomeric nucleotide with three consecutive phosphate groups attached rather than one. These phosphate groups are joined by high energy phosphate-to-oxygen-to-phosphate covalent bonds that can provide energy to activities in the cell that need energy.NADH is a dinucleotide molecule that can store energy obtained from the breakdown of food molecules. This energy will later be transferred to a series of molecules to synthesize more ATP when cells need it.30. All enzymes have a range of pH at which they are active, as well as an optimal pH at which they are most active. For example, salivary amylase is active in a pH range of 4.7 to 9.0, but it operates best in an environment with a pH of 6.9.31. As the graph shows, pepsin only remains active up to a pH of about 4.8. If the pH is any higher than this, the pepsin's folds will become so distorted that its active site will no longer function. Thus, pepsin is only able to catalyze the digestion of proteins in the highly acidic environment of the stomach.32. Carbohydrates and nucleic acids are extremely polar due to the large number of oxygen atoms in these organic molecules. Polar organic molecules are able to form hydrogen bonds with the polar water molecules, allowing them to dissolve easily in water.In contrast, lipids have very little oxygen, and are mainly nonpolar. Also, lipids are less dense than water. Due to these two characteristics, the lipids form a layer above the water in the mixture.33. Imagine that you need to turn a nut onto the end of a bolt. You could do it by hand, but it would be faster and require less energy if you used a power tool instead. Then, once you were done with that bolt, you could use the same power tool on a different bolt.An enzyme is like a power tool because, by definition, catalysts speed up chemical reactions without being used up by the reaction. So, once an enzyme has finished catalyzing one reaction, it can move on and catalyze another reaction, because it is not used up by the reaction.34. A fat is a kind of lipid that can store energy for a long period of time. Fats are made up of long chains of carbon and oxygen atoms bonded to a backbone structure. This backbone structure is often glycerol.Fats are important because they are a major source of energy. Since they contain even more carbon-hydrogen bonds than carbohydrates, fatty tissue has the ability to store energy for extended periods of time.35. The shape of an enzyme determines how it works. Most enzymes have a surface with one or more deep folds. The folds make pockets which are called active sites.The active sites match folds in the substrate's surface, like a key matches a lock, so the enzyme only catalyzes specific reactions. Once an enzyme binds to a substrate, the amount of energy needed to start a chemical reaction with the substrate is reduced.36. Amino acids are the building blocks of proteins. If the enzyme catalyzes a reaction that involves the breakdown of a protein, amino acids would result. Amino acids would not result if the molecule was a carbohydrate, lipid, or mineral.37. Enzymes can only function within a narrow pH range. If the pH is too high (too basic) or too low (too acidic), the enzyme changes its shape and is no longer effective.Since enzymes play an important role in nearly all cellular processes, cells can only function within a specific pH range, too. Cells do not function well at pH's that are too high or too low.38. Most cell function best within a narrow range of temperature and acidity.At very low temperatures, reaction rates are too slow. High temperatures and/or extremes of acidity can irreversibly change the structure of most protein molecules. Even small changes in acidity can alter the molecules and how they interact.39. Carbohydrates, like sugars and starches, are composed of carbon, hydrogen, and oxygen.40. Nucleic acids, such as DNA, are formed from nucleotide monomers. Nucleotides are chemical compounds that consist of a five-carbon sugar, a nitrogenous base, and one or more phosphate groups. All nucleic acids, including DNA, are organic molecules.41. Enzymes are substances that cause chemical reactions to occur faster.42. Many people are lactose intolerant, meaning that they have difficulty digesting food that contains large amounts of lactose. This occurs because a person's body does not produce enough lactase enzyme, which is the enzyme needed to quickly breakdown lactose.43. Enzymes are catalysts that increase the rate of chemical reactions by decreasing the amount of energy needed to activate the chemical reaction.Enzymes are not consumed during a chemical reaction and, therefore, once an enzyme has finished catalyzing one reaction, it can move on and catalyze another reaction. Enzymes are also specific to particular molecules based on their shape and size. Enzymes do not, however, increase the amount of energy produced by a chemical reaction.Only I and II are characteristics of enzymes.44. Carbon atoms can bond with many other kinds of atoms to form very stable molecules. This is because carbon atoms have four electrons in their outer shells, and all four are available for bonding.Carbon can share these electrons in single bonds with up to four other atoms to form very stable structures. Alternatively, carbon can form double bonds with up to two other atoms by sharing two electrons with each. Carbon can also form a combination of double and single bonds, as long as no more than four electrons are donated.45. The enzyme catalase is most effective when the reaction rate is at its peak (1 ml/s). This occurs between 27°C and 37°C, approximately.Between approximately 60°C and 100° C, the rate of the reaction is equal to 0?ml/s. At these temperatures, the enzyme catalase is denatured. That is, the structure of the enzyme changes, so it is no longer able to catalyze reactions.46. Carbohydrates are organic macromolecules that are made up of carbon, hydrogen, and oxygen atoms. These atoms are combined in a ratio of1 carbon atom : 2 hydrogen atoms : 1 oxygen atomCarbohydrates may be simple or complex and are typically used for energy storage or as structural molecules. Examples of carbohydrates include glucose, cellulose, starch, and fructose.47. Carbon atoms have four electrons in their outer shells, and all four are available for bonding. Carbon can share these electrons in single bonds with up to four other atoms to form very stable structures. Alternatively, carbon can form double bonds with up to two other atoms by sharing two electrons with each. Carbon can also form a combination of double and single bonds, as long as no more than four electrons are donated.48. In addition to being an energy source for living organisms, carbohydrates play a structural role, as well. Cellulose, for example, is a carbohydrate found in plant cell walls.Keratin, collagen, and enzymes are all examples of proteins, not carbohydrates.49. In the presence of excess molecules, there is a direct relationship between the enzyme concentration and the reaction rate. As the enzyme concentration increases, the reaction rate also increases.If this experiment were not performed with excess molecules, the results would initially be the same, but the reaction rate would eventually plateau once all the molecules were used up.50. Enzymes reduce the activation energy (the energy reactants need to absorb) of chemical reactions. This allows the reaction to speed up. Reaction B was most likely catalyzed by an enzyme because it took a low amount of energy to start and the reaction was fast compared to Reactions C and D.51. In most animal cells, a complex network of proteins provides organization, shape, and movement. In all cells, other than very primitive ones, the network of proteins provides organization and shape.Most of these structural proteins that provide organization and shape are fibrous proteins, such as actin and tubulin. Most of the motor proteins are made up of myosin and kinesin.52. Protein molecules are composed of long chains of amino acids and perform many functions in the human body. The function of a protein molecule is determined by the sequence of its amino acids and its shape/folded structure.Proteins do not, however, store genetic information. Genetic information is stored by sequences of DNA.53. According to the chemical equation, water and oxygen are produced when hydrogen peroxide is broken down. The enzyme catalase speeds up this reaction.54. Nucleic acids are formed from nucleotide monomers and are primarily comprised of the elements carbon, hydrogen, oxygen, nitrogen, and phosphorus. They always consist of a five-carbon sugar, a nitrogenous base, and one or more phosphate groups.There are two main types of nucleic acids - ribonucleic acids (RNA) and deoxyribonucleic acids (DNA). These nucleic acids are different because their five-carbon sugars are different. RNA contains ribose, and DNA contains deoxyribose. DNA and RNA also have different functions. DNA stores genetic information and encodes the sequences of all the cell's proteins whereas RNA is involved in the direct production of the proteins.Only I and II are true about nucleic acids. Lipids are usually insoluble in water and are used for long term energy storage. Glucose, cellulose, and starch are examples of carbohydrates.55. Enzymes have very unique shapes that allow them to bind to specific molecules and catalyze specific reactions. Thus, an enzyme-substrate complex can best be compared to a lock and key.56. Nucleotide monomers contain a five-carbon sugar, a phosphate group, and a nitrogenous base.In DNA, the five-carbon sugar is deoxyribose and the nitrogenous base could be adenine, thymine, cytosine, or guanine. In RNA, the five-carbon sugar is ribose and the nitrogenous base could be adenine, uracil, cytosine, or guanine.Glucose is a six-carbon sugar found in other biological polymers like starch and cellulose. Amino acids are the monomer units of proteins.57. Due to the abundance of carbon-hydrogen bonds present in lipids, they are primarily used as a source of energy for living organisms. Lipids, however, are found in a variety of other roles, too.Lipids are found in some fat-soluble vitamins and naturally occurring steroids, such as estrogen and testoterone. Lipids are found in biological membranes and other waterproof coverings, such as plasma membranes and the intracellular membranes of cellular organelles. Lipids are also found in food in the form of saturated and unsaturated fats. Butter, cheese, oils, chocolate, beef, fish, and mayonnaise are among the many foods in which fats are found.58. Organic macromolecules called lipids are insoluble in water which is why lipids are often found in biological membranes and other waterproof coverings. Lipids also play a vital role in insulation, regulating which substances can or cannot enter a cell, and they have the ability to store energy for extended periods of time.59. --60. Sugars such as glucose, fructose, and ribose are all examples of monosaccharides, or simple carbohydrates.Carbohydrates are organic macromolecules that are made up of carbon, hydrogen, and oxygen atoms. These atoms are combined in a ratio of1 carbon atom : 2 hydrogen atoms : 1 oxygen atomSimple carbohydrates can bond together to make polysaccharides, or larger, more complex carbohydrates, such as starch or cellulose.Carbohydrates are typically used for energy storage or as structural molecules. ................
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