2. Chapter Intro-page 140 What You’ll Learn You will relate an atom’s interactions with other atoms to its structure. You will explain why water is important in life. You will compare the role of biomolecules in organisms.

3. 6.1 Section Objectives – page 141 Relate the structure of an atom to the identity of elements. Section Objectives: Relate the formation of covalent and ionic chemical bonds to the stability of atoms.

4. 6.1 Section Objectives – page 141 Section Objectives: Distinguish mixtures and solutions. Define acids and bases and relate their importance to biological systems.

5. An element is a substance that can’t be broken down into simpler chemical substances. Section 6.1 Summary – pages 141-151 Elements Everything – whether it is a rock, frog, or flower – is made of substances called elements.

6. Section 6.1 Summary – pages 141-151 Of the naturally occurring elements on Earth, only about 25 are essential to living organisms. Carbon, hydrogen, oxygen, and nitrogen make up more that 96 percent of the mass of a human body. Natural elements in living things

7. Section 6.1 Summary – pages 141-151 Trace elements Trace elements such as iron and copper, play a vital role in maintaining healthy cells in all organisms. Plants obtain trace elements by absorbing them through their roots; animals get them from the foods they eat.

8. Section 6.1 Summary – pages 141-151 Table 6.1 Some Elements That Make Up the Human Body ElementSymbol Percent By Mass in Human Body Element Symbol Percent By Mass in Human Body Molybdenum Oxygen Carbon Hydrogen Nitrogen Calcium Phosphorus Potassium Sulfur Sodium Chlorine Magnesium Selenium Iron Zinc Copper Iodine Manganese Boron Chromium Cobalt Fluorine O C H N Ca P K S Na Cl Mg 65.0 18.5 9.5 3.3 1.5 1.0 0.4 0.3 0.2 0.1 Fe Zn Cu I Mn B Cr Mo Co Se F trace

9. An atom is the smallest particle of an element that has the characteristics of that element. Section 6.1 Summary – pages 141-151 Atoms: The Building Blocks of Elements Atoms are the basic building blocks of all matter.

10. All nuclei contain positively charged particles called protons (p + ). The center of an atom is called the nucleus (NEW klee us). Section 6.1 Summary – pages 141-151 The structure of an atom Most contain particles that have no charge, called neutrons (n 0 ).

11. Section 6.1 Summary – pages 141-151 The Structure of an atom Nucleus Electron energy levels The region of space surrounding the nucleus contains extremely small, negatively charged particles called electrons (e - ) This region of space is referred to as an electron cloud.

12. Section 6.1 Summary – pages 141-151 The Structure of an atom Because opposites attract, the negatively charged electrons are held in the electron cloud by the positively charged nucleus.

13. Section 6.1 Summary – pages 141-151 Electron energy levels Electrons exist around the nucleus in regions known as energy levels. The first energy level can hold only two electrons. The second level can hold a maximum of eight electrons. The third level can hold up to 18 electrons. Nucleus 8 protons (p+) 8 neutrons (n 0 ) Oxygen atom

14. Section 6.1 Summary – pages 141-151 Electron energy levels Atoms contain equal numbers of electrons and protons; therefore, they have no net charge.

15. Section 6.1 Summary – pages 141-151 Atoms of the same element always have the same number of protons but may contain different numbers of neutrons. Isotopes of an Element Atoms of the same element that have different numbers of neutrons are called isotopes (I suh tophs) of that element.

16. Section 6.1 Summary – pages 141-151 A compound is a substance that is composed of atoms of two or more different elements that are chemically combined. Compounds and Bonding Table salt (NaCl) is a compound composed of the elements sodium and chlorine.

17. Section 6.1 Summary – pages 141-151 Atoms combine with other atoms only when the resulting compound is more stable than the individual atoms. How covalent bonds form For many elements, an atom becomes stable when its outermost energy level is full. Sharing electrons with other atoms is one way for elements to become stable.

18. Section 6.1 Summary – pages 141-151 Two hydrogen atoms can combine with each other by sharing their electrons. How covalent bonds form Each atom becomes stable by sharing its electron with the other atom. Hydrogen molecule

19. Section 6.1 Summary – pages 141-151 How covalent bonds form Click image to view movie.

20. Section 6.1 Summary – pages 141-151 How covalent bonds form The attraction of the positively charged nuclei for the shared, negatively charged electrons holds the atoms together. Hydrogen molecule

21. Section 6.1 Summary – pages 141-151 A covalent bond holds the two hydrogen atoms together. How covalent bonds form A molecule is a group of atoms held together by covalent bonds. It has no overall charge. Water molecule

22. Section 6.1 Summary – pages 141-151 An atom (or group of atoms) that gains or loses electrons has an electrical charge and is called an ion. An ion is a charged particle made of atoms. How ionic bonds form The attractive force between two ions of opposite charge is known as an ionic bond. Click image to view movie.

23. Section 6.1 Summary – pages 141-151 Chemical reactions occur when bonds are formed or broken, causing substances to recombine into different substances. Chemical Reactions Ionic bond + Sodium atom + Chlorine atom Sodium + Ion + Chlorine ― ion Na atom: 11p + 11e ― Cl atom: 17p + 17e ― Na + ion: 11p + 10e ― Cl ― ion: 17p + 18e ―

24. All of the chemical reactions that occur within an organism are referred to as that organism’s metabolism. Section 6.1 Summary – pages 141-151 Chemical Reactions Ionic bond + Sodium atom + Chlorine atom Sodium + Ion + Chlorine ― ion Na atom: 11p + 11e ― Cl atom: 17p + 17e ― Na + ion: 11p + 10e ― Cl ― ion: 17p + 18e ―

25. Section 6.1 Summary – pages 141-151 In a chemical reaction, substances that undergo chemical reactions, are called reactants. Writing chemical equations Substances formed by chemical reactions, are called products.

26. Section 6.1 Summary – pages 141-151 A molecule of table sugar can be represented by the formula: C 12 H 22 O 11. Writing chemical equations The easiest way to understand chemical equations is to know that atoms are neither created nor destroyed in chemical reactions. They are simply rearranged.

27. A mixture is a combination of substances in which the individual components retain their own properties. Section 6.1 Summary – pages 141-151 Mixtures and Solutions Neither component of the mixture changes.

28. Section 6.1 Summary – pages 141-151 A solution is a mixture in which one or more substances (solutes) are distributed evenly in another substance (solvent). Mixtures and Solutions Sugar molecules in a powdered drink mix dissolve easily in water to form a solution.

29. Section 6.1 Summary – pages 141-151 Chemical reactions can occur only when conditions are right. Acids and bases A reaction may depend on: - energy availability - temperature - concentration of a substance - pH of the surrounding environment

30. Section 6.1 Summary – pages 141-151 The pH is a measure of how acidic or basic a solution is. Acids and bases A scale with values ranging from below 0 to above 14 is used to measure pH. More acidic NeutralMore basic

31. Section 6.1 Summary – pages 141-151 Substances with a pH below 7 are acidic. An acid is any substance that forms hydrogen ions (H + ) in water. Acids and bases A solution is neutral if its pH equals zero. More acidic NeutralMore basic

32. Section 6.1 Summary – pages 141-151 Substances with a pH above 7 are basic. A base is any substance that forms hydroxide ions (OH - ) in water. Acids and bases pH 11

33. Section 1 Check Question 1 Which of the following is an element? D. water C. sodium chloride B. carbon A. chlorophyll NC: 2.01

34. Section 1 Check The answer is B. An element can't be broken down into simpler chemical substances. Chemical elements combine in different ways to form a variety of substances useful to living things. NC: 2.01

35. Section 1 Check Table 6.1 Some Elements That Make Up the Human Body ElementSymbol Percent By Mass in Human Body Element Symbol Percent By Mass in Human Body Molybdenum Oxygen Carbon Hydrogen Nitrogen Calcium Phosphorus Potassium Sulfur Sodium Chlorine Magnesium Selenium Iron Zinc Copper Iodine Manganese Boron Chromium Cobalt Fluorine O C H N Ca P K S Na Cl Mg 65.0 18.5 9.5 3.3 1.5 1.0 0.4 0.3 0.2 0.1 Fe Zn Cu I Mn B Cr Mo Co Se F trace NC: 2.01

36. Section 1 Check The smallest particle of an element that has the characteristics of that element is a(n) __________. Question 2 D. atom C. nucleus B. electron A. proton

37. Section 1 Check The answer is D. Atoms are the basic building blocks of all matter and have the same general structure, including a nucleus and electrons. Elements found in both living and nonliving things are made of atoms. Nucleus Electron energy levels An atom has a nucleus and electrons in energy levels.

38. Section 1 Check Which of the following can contain two types of particles? D. electrons Question 3 B. protons C. neutrons A. nucleus

39. Section 1 Check The answer is A. The nucleus is the center of the atom and may contain both positively charged particles and particles that have no charge. Nucleus 8 protons (p+) 8 neutrons (n 0 ) Oxygen atom

40. Section 1 Check Question 4 B. Sodium and chlorine atoms have no overall electrical charge. A. Sodium and chlorine are sharing electrons in their outer energy levels. Sodium and chlorine combine to form table salt. What do you know to be true?

41. Section 1 Check Question 4 D. Sodium and chlorine atoms in table salt have full outer energy levels. C. Sodium and chlorine are less stable in the compound sodium chloride. Sodium and chlorine combine to form table salt. What do you know to be true?

42. Section 1 Check The answer is D. Sodium and chlorine atoms combine because the resulting compound, table salt, is more stable than the individual atoms. Sodium loses an electron in its outer energy level, chlorine gains that electron in its outer energy level, and an ionic bond is formed.

43. Section 2 Objectives – page 152 Section Objectives Identify how the process of diffusion occurs and why it is important to cells. Relate water’s unique features to polarity.

44. Summary Section 2 – pages 152-156 Water is perhaps the most important compound in living organisms. Water and Its Importance Water makes up 70 to 95 percent of most organisms.

45. Summary Section 2 – pages 152-156 Water is Polar Sometimes, when atoms form covalent bonds they do not share the electrons equally. This is called a polar bond.

46. Summary Section 2 – pages 152-156 Water is Polar A polar molecule is a molecule with an unequal distribution of charge; that is, each molecule has a positive end and a negative end. Water is an example of a polar molecule. Water can dissolve many ionic compounds, such as salt, and many other polar molecules, such as sugar.

47. Summary Section 2 – pages 152-156 Water is Polar Water molecules also attract other water molecules. Weak hydrogen bonds are formed between positively charged hydrogen atoms and negatively charged oxygen atoms. Hydrogen atom Oxygen atom

48. Summary Section 2 – pages 152-156 Water resists changes in temperature. Therefore, water requires more heat to increase its temperature than do most other common liquids. Water resists temperature changes

49. Summary Section 2 – pages 152-156 Water expands when it freezes Water is one of the few substances that expands when it freezes. Ice is less dense than liquid water so it floats as it forms in a body of water.

50. Summary Section 2 – pages 152-156 Early observations: Bownian motion In 1827, Scottish scientist Robert Brown used a microscope to observe pollen grains suspended in water. He noticed that the grains moved constantly in little jerks, as if being struck by invisible objects. This motion is now called Brownian motion. Today we know that Brown was observing evidence of the random motion of atoms and molecules.

51. Summary Section 2 – pages 152-156 The process of diffusion Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration. Diffusion results because of the random movement of particles (Brownian motion). Three key factors—concentration, temperature, and pressure—affect the rate of diffusion.

52. Summary Section 2 – pages 152-156 The results of diffusion When a cell is in dynamic equilibrium with its environment, materials move into and out of the cell at equal rates. As a result, there is no net change in concentration inside or outside the cell. Material moving out of cell equals material moving into cell

53. Summary Section 2 – pages 152-156 Diffusion in living systems The difference in concentration of a substance across space is called a concentration gradient. Ions and molecules diffuse from an area of higher concentration to an area of lower concentration, moving with the gradient. Dynamic equilibrium occurs when there is no longer a concentration gradient.

54. Section 2 Check Explain why water is important to living organisms. Question 1 Living organisms must have water for life processes, because critical molecules and ions must be free to move and collide, which only happens when they are dissolved in water. Water also transports materials in living organisms, such as in blood or sap. Answer

55. Section 2 Check How does water's chemical structure impact its role in living organisms? Question 2 Positively charged end Negatively charged end + + ― NC: 2.03

56. Section 2 Check Because water is polar, it can dissolve many ionic compounds and polar molecules. Water has the property of capillary action that enables plants to get water from the ground. Water also resists temperature changes, which allows cells to maintain homeostasis. NC: 2.03

57. Section 2 Check Which of the following best describes diffusion? Question 3 B. net movement of particles from area of low concentration to area of high concentration A. slow process resulting from random movement of particles NC: 2.03

58. Section 2 Check D. net movement of particles from high to low concentrations that accelerates when pressure decreases C. rapid process that is unaffected by increases in temperature Which of the following best describes diffusion? Question 3 NC: 2.03

59. Section 2 Check The answer is A. Diffusion is a slow process resulting from the random movement of particles, and is the net movement of particles from areas of high concentration to areas of lower concentration. NC: 2.03

60. 6.3 Section Objectives – page 157 Classify the variety of organic compounds. Section Objectives: Describe how polymers are formed and broken down in organisms. Compare the chemical structures of carbohydrates, lipids, proteins, and nucleic acids, and relate their importance to living things. Identify the effects of enzymes.

61. Inorganic Compounds Water= H 2 O Derived from nonliving things Does not contain more than one carbon atom Ex. : CO 2, H 2 O

62. Metabolism Metabolism= all chemical reactions in the body

63. 6.3 Section Summary 6.3 – pages 157-163 A carbon atom has four electrons available for bonding in its outer energy level. In order to become stable, a carbon atom forms four covalent bonds that fill its outer energy level. The Role of Carbon in Organisms

64. 6.3 Section Summary 6.3 – pages 157-163 The Role of Carbon in Organisms Two carbon atoms can form various types of covalent bonds—single, double or triple. Single Bond Double BondTriple Bond

65. 6.3 Section Summary 6.3 – pages 157-163 Carbon compounds vary greatly in size. Molecular chains When carbon atoms bond to each other, they can form straight chains, branched chains, or rings.

66. 6.3 Section Summary 6.3 – pages 157-163 Molecular chains Small molecules bond together to form chains called polymers. A polymer is a large molecule formed when many smaller molecules bond together.

67. 6.3 Section Summary 6.3 – pages 157-163 A carbohydrate is a biomolecule composed of carbon, hydrogen, and oxygen. Sometimes referred to as sugars Ratio of two hydrogen atoms and one oxygen atom for every carbon atom The structure of carbohydrates

68. 6.3 Section Summary 6.3 – pages 157-163 The structure of carbohydrates The simplest type of carbohydrate is a simple sugar called a monosaccharide, 1 ring sugars. Gluclose- C 6 H 12 O 6 Fructose- C 6 H 12 O 6 Ribose- C 5 H 10 O 5 Glucose and Fructose are structurally different!

69. Disaccharides Carbohydrates also form disaccharides, 2 ring sugars (ie. Sucrose) Sucrose- C 12 H 22 O 11 Maltose- C 12 H 22 O 11 Sucrose and maltose are structurally different!

70. Polysaccharides The largest carbohydrate molecules are polysaccharides, many ring sugars (ie. potatoes, liver)

71. Sugars

72. Dehydration Synthesis and Hydrolysis In Dehydration Synthesis, the small molecules that are bonded to make together to make a polymer (monosaccharide) have a H atom and an OH group that can be removed to form a water molecule. The subunits then become bonded by a covalent bond The reverse process (adding water) is called hydrolysis

73. Carbohydrates Glucose (C 6 H 12 O 6 ) –The most important monosaccharide –The basic form of fuel in living things Cellulose –Made of long chains of glucose units linked together –Forms cell walls of plants, and gives structural support

74. Carbohydrates Glycogen –Polysaccharide –Mammals store energy in the liver in the form of glycogen Starch –Used as energy storage in plants –Most common carb in human diets –Potatoes, rice, wheat

75. 6.3 Section Summary 6.3 – pages 157-163 Lipids are large biomolecules made mostly of carbon and hydrogen with a small amount of oxygen. The structure of lipids They are insoluble in water. Their molecules are nonpolar and are not attracted by water.

76. Lipids Fats, oils and waxes are all examples

77. Structure of Lipids Lipids are built by fatty acids (monomers) –Saturated Fatty Acids only contain single bonds Examples would be butter, meat and dairy products

78. Structure of Lipids Unsaturated Fatty Acids contain one double bond –Example would be vegetable oil

79. Structure of Lipids Polyunsaturated Fatty acids contain multiple double bonds Example: Peanut Butter

80. Steroids Steroids are a special type of lipid Four fused carbon rings form the skeleton of all steroids Steroids are present in everyone! –Cholesterol is a steroid –Estrogen and Testosterone are both steroids

81. Phospholipids Phospholipids are important in cells. The “head” of a phospholipid is polar, and is attracted to water. The “tail” is nonpolar and is not attracted to water. They form a phospholipid bilayer crucial to the formation of plasma membranes.

83. 6.3 Section Summary 6.3 – pages 157-163 A protein is a polymer composed of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. Sometimes called a polypeptide because the monomers are joined by peptide bonds The structure of proteins

84. 6.3 Section Summary 6.3 – pages 157-163 The structure of proteins The basic building blocks of proteins are called amino acids. There are about 20 common amino acids that can make literally thousands of proteins.

85. 6.3 Section Summary 6.3 – pages 157-163 Peptide bonds are covalent bonds formed between amino acids. The structure of proteins Remove an OH from the carboxyl group Remove an H from the amino group <-

86. How a Protein becomes Functional Primary Structure: specific sequence of amino acids

87. How a Protein Becomes Functional Secondary Structure: two or more primary structures curl to form a spiral called an alpha helix

88. How a Protein Becomes Functional Tertiary Structure: the final 3d structure of a protein. Held in place by interactions of hydrogen molecules.

89. How a Protein Becomes Functional Quaternary Structure: two or more of the tertiary subunits joined together, makes a single, larger protein!

90. 6.3 Section Summary 6.3 – pages 157-163 Proteins are the building blocks of many structural components of organisms. If a protein becomes denatured, it may uncurl, causing the protein to be unable to perform its part in the cell. Ex. Fry an Egg Our bodies can still use the amino acids in the egg to make new proteins The structure of proteins

91. The Function of Proteins Provide structure for tissue and organs and carry out cell metabolism Move muscles –Actin and Myosin Transporting oxygen in blood –Hemoglobin Providing protection –Antibodies –Keratin

92. Functions of Proteins Regulate other proteins –Hormones Carries out functions –Enzymes

93. 6.3 Section Summary 6.3 – pages 157-163 Enzymes Enzymes are important proteins found in living things. An enzyme is a protein that changes the rate of a chemical reaction. They speed the reactions in digestion of food. Enzymes are made of amino acids Click image to view movie.

94. Enzymes Enzymes are very specific –They only work with their substrate Substrates are the molecules upon which enzymes act Lock and Key hypothesis –Addition to your notes

95. Lock and Key Hypothesis Enzymes have active sites to which the substrate attaches The substrate contains the reactive site, where it bonds to the enzyme

96. Enzymes

97. Increase the rate of chemical reactions Lower the activation energy –The amount of energy required to make the reaction start

99. Identifying Enzymes Most enzymes end with the suffix –ase, except for very few circumstances These identify the substrate they break down –Ex. Sucrase breaks down Sucrose Found in many detergents

100. 6.3 Section Summary 6.3 – pages 157-163 A nucleic acid is a biomolecule that stores cellular information in the form of a code. The structure of nucleic acids Nucleic acids are polymers made of smaller subunits called nucleotides.

101. Nucleic Acids Nucleic acids code for how each protein should be made They control all of the cells functional processes

102. 6.3 Section Summary 6.3 – pages 157-163 The structure of nucleic acids Nucleotides are arranged in three groups—a nitrogenous base, a simple sugar, and a phosphate group. Phosphate Sugar Nitrogenous base

103. Nucleotides Nucleotides: 5 types Adenine- A Thymine- T Guanine- G Cytosine- C Uracil- U These are the same for all organisms These code your DNA

104. 6.3 Section Summary 6.3 – pages 157-163 DNA, which stands for deoxyribonucleic acid is a nucleic acid. The structure of nucleic acids Phosphate Sugar Nitrogenous base

105. 6.3 Section Summary 6.3 – pages 157-163 The structure of nucleic acids The information coded in DNA contains the instructions used to form all of an organism’s enzymes and structural proteins. Another important nucleic acid is RNA, which stands for Ribonucleic acid. RNA is a nucleic acid that helps to form DNA for use in making proteins.

106. Section 3 Check Carbon needs 4 covalent bonds to become stable. True/ False True

107. True/ False Nucleotides are the monomers of carbohydrates. False Nucleotides are the monomers of nucleic acids

108. True/False Enzymes can only work with one specific substrate True

109. True/ False Unsaturated fatty acids contain 1 double bond True

110. True/ False Enzymes slow down chemical reactions inside your body False Enzymes speed up chemical reactions

111. A __________ is a biomolecule composed of carbon, hydrogen, and oxygen with a ratio of about two hydrogen atoms and one oxygen atom for every carbon atom. Multiple Choice D. fatty acid C. protein B. lipid A. carbohydrate Section 3 Check NC: 2.01

112. The answer is A. Lipids are made mostly of carbon and hydrogen, and proteins contain nitrogen in addition to carbon, hydrogen and oxygen. Section 3 Check NC: 2.01

113. In which type of molecule will you find peptide bonds? Question 3 D. fatty acid C. protein B. lipid A. carbohydrate Section 3 Check

114. The answer is C. Amino acids are the basic building blocks of proteins and are linked together by peptide bonds. Section 3 Check

115. What biomolecule is represented in this diagram? Question 4 D. lipid C. protein B. nucleotide A. carbohydrate Phosphate Sugar Nitrogenous base Section 3 Check

116. The answer is B. Nucleotides are the smaller subunits that make up nucleic acids. Nucleotides are composed of three groups: a nitrogenous base, a simple sugar, and a phosphate group. Phosphate Sugar Nitrogenous base Section 3 Check

117. Describe an enzyme and its function. Question 5 Section 3 Check NC: 2.04

118. An enzyme is a protein that enables other molecules to undergo chemical changes to form new products. Enzymes increase the speed of reactions that would otherwise proceed too slowly. Substrate Active site Section 3 Check NC: 2.04

119. Chapter Summary – 6.1 Atoms are the basic building block of all matter. Atoms and Their Interactions Atoms consist of a nucleus containing protons and usually neutrons. The positively charged nucleus is surrounded by rapidly moving, negatively charged electrons. Atoms become stable by bonding to other atoms through covalent or ionic bonds.

120. Chapter Summary – 6.1 Components of mixtures retain their properties. Atoms and Their Interactions Solutions are mixtures in which the components are evenly distributed. Acids are substances that from hydrogen ions in water. Bases are substances that form hydroxide ions in water.

121. Chapter Summary – 6.2 Water is the most abundant compound in living things. Water and Diffusion Water is an excellent solvent due to the polar property of its molecules. Particles of matter are in constant motion. Diffusion occurs from areas of higher concentration to areas of lower concentration.

122. Chapter Summary – 6.3 All organic compounds contain carbon atoms. Life Substances There are four principal types of organic compounds, or biomolecules, that make up living things: carbohydrates, lipids, proteins, and nucleic acid. The structure of a biomolecule will help determine its properties and functions.

123. Chapter Assessment Question 1 What is the difference between a compound and an element? Answer A compound is a substance that is composed of atoms of two or more different elements that are chemically combined. An element is a substance that can't be broken down into simpler chemical substances.

124. Question 2 What is it called when atoms share electrons? D. diffusion C. hydrogen bonding B. ionic bonding Water molecule A. covalent bonding Chapter Assessment

125. The answer is A. Covalent bonds differ from ionic bonds in that the shared electrons move about the nuclei of both atoms of the covalent compound. Water molecule Chapter Assessment

126. Question 3 Which of the following combinations will produce a solution? D. oil and vinegar C. powdered drink mix and water B. sand and sugar crystals A. chocolate chips and cookie dough Chapter Assessment

127. The answer is C. All of the combinations are mixtures because the individual components retain their own properties. A solution is a mixture in which one or more substances is dissolved in another and will not settle out of solution. Water molecules Sugar molecules Sugar crystal Chapter Assessment

128. Question 4 What type of substance forms hydrogen ions in water? D. polar C. base B. acid A. enzyme Chapter Assessment

129. The answer is B. Any substance that forms hydrogen ions (H + ) in water is an acid. The pH of a substance is a measure of how acidic or basic a solution is. Chapter Assessment

130. Question 5 Which of the following best describes a molecule with an unequal distribution of charge? D. diffuse C. basic B. acidic A. polar Chapter Assessment NC: 2.02

131. The answer is A. Each polar molecule has a positive end and a negative end. Polar water molecules attract ions and other polar molecules, and can dissolve many ionic compounds. Chapter Assessment NC: 2.02

132. Question 6 Name the chemical reaction illustrated in the diagram. B. condensation Glucose Fructose Sucrose CH 2 OH O OH CH 2 OH HO OH HO O HOCH 2 CH 2 OH + H2OH2O O OH HO OH O HOCH 2 OH HO O + CH 2 OH D. glycolysis C. Protein synthesis A. hydrolysis Chapter Assessment NC: 2.03

133. The answer is B. In condensation reactions, small molecules bond together to produce a polymer and water. Glucose Fructose Sucrose CH 2 OH O OH CH 2 OH HO OH HO O HOCH 2 CH 2 OH + H2OH2O O OH HO OH O HOCH 2 OH HO O + CH 2 OH Chapter Assessment NC: 2.03

134. Question 7 An oxygen atom has 8 protons and 8 neutrons. How many electrons does it have? D. 0 C. 32 B. 18 A. 8 Chapter Assessment

135. The answer is A. Atoms contain equal numbers of electrons and protons and have no net charge. Nucleus 8 protons (p+) 8 neutrons (n 0 ) Oxygen atom Chapter Assessment

136. Question 8 Based on your knowledge of biomolecules, which of the following substances would be most effective at breaking down this polymer? B. lipase CH 2 OH O OH HO OH O HOCH 2 OH HO O CH 2 OH D. water C. pepsin A. nuclease Chapter Assessment NC: 2.01

137. The answer is D. This is a sucrose molecule, formed from glucose and fructose in a condensation reaction. The products of this reaction are the sucrose molecule and water. If water is added to sucrose, hydrolysis occurs and breaks the covalent bonds between the subunits. Chapter Assessment NC: 2.01

138. Photo Credits Aaron Haupt Corbis Digital Stock Elaine Shay Mark Thayer PhotoDisc Alton Biggs Photo Credits

139. To advance to the next item or next page click on any of the following keys: mouse, space bar, enter, down or forward arrow. Click on this icon to return to the table of contents Click on this icon to return to the previous slide Click on this icon to move to the next slide Click on this icon to open the resources file. Help

140. End of Chapter 6 Show