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Standardized Test Prep
Resources Chapter Presentation Visual Concepts Transparencies Standardized Test Prep
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Chapter 2 Table of Contents Section 1 Nature of Matter
Chemistry of Life Table of Contents Section 1 Nature of Matter Section 2 Water and Solutions Section 3 Chemistry of Cells Section 4 Energy and Chemical Reactions
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Chapter 2 Objectives Differentiate between atoms and elements.
Section 1 Nature of Matter Objectives Differentiate between atoms and elements. Analyze how compounds are formed. Distinguish between covalent bonds, hydrogen bonds, and ionic bonds.
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Chapter 2 Section 1 Nature of Matter Matter
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Chapter 2 Section 1 Nature of Matter Atoms An atom is the smallest unit of matter that cannot be broken down by chemical means. As shown below, an atom consists of three kinds of particles: electrons, protons, and neutrons.
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Chapter 2 Section 1 Nature of Matter Atom
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Chapter 2 Atoms, continued Elements
Section 1 Nature of Matter Atoms, continued Elements An element is a pure substance made of only one kind of atom. Elements differ in the number of protons their atoms contain. The number of neutrons in an atom is often but not always equal to the number of protons in the atom.
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Chapter 2 Section 1 Nature of Matter Element
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Chapter 2 Chemical Bonding
Section 1 Nature of Matter Chemical Bonding Atoms can join with other atoms to form stable substances. A force that joins atoms is called a chemical bond. A compound is a substance made of the joined atoms of two or more different elements.
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Chapter 2 Section 1 Nature of Matter Compounds
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Chemical Bonding, continued
Chapter 2 Section 1 Nature of Matter Chemical Bonding, continued Covalent Bonds Covalent bonds form when two or more atoms share electrons to form a molecule. A molecule such as the water molecule shown below, is a group of atoms held together by covalent bonds.
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Chapter 2 Section 1 Nature of Matter Molecule
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Chemical Bonding, continued
Chapter 2 Section 1 Nature of Matter Chemical Bonding, continued Covalent Bonds The arrangement of their electrons determines how atoms bond together. An atom becomes stable when its outer electron level is full. If the outer electron level is not full, an atom will react readily with atoms that can provide electrons to fill its outer level.
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Chapter 2 Section 1 Nature of Matter Covalent Bonding
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Chemical Bonding, continued
Chapter 2 Section 1 Nature of Matter Chemical Bonding, continued Hydrogen Bonds In a water molecule, the shared electrons are attracted more strongly by the oxygen nucleus than by the hydrogen nuclei. Molecules with an unequal distribution of electrical charge, such as water molecules, are called polar molecules. This attraction between two water molecules is an example of a hydrogen bond—a weak chemical attraction between polar molecules.
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Chemical Bonding, continued
Chapter 2 Section 1 Nature of Matter Chemical Bonding, continued Hydrogen Bonds Water molecules are attracted to each other by hydrogen bonds.
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Chapter 2 Section 1 Nature of Matter Hydrogen Bonding
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Chemical Bonding, continued
Chapter 2 Section 1 Nature of Matter Chemical Bonding, continued Ionic Bonds Sometimes atoms or molecules gain or lose electrons. An atom or molecule that has gained or lost one or more electrons is called an ion. Ions have an electrical charge because they contain an unequal number of electrons and protons. Ions of opposite charge may interact to form an ionic bond.
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Chapter 2 Section 1 Nature of Matter Ion
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Chemical Bonding, continued
Chapter 2 Section 1 Nature of Matter Chemical Bonding, continued Ionic Bonds Ionic bonds in sodium chloride, NaCl, are formed by the interaction between sodium ions, Na+, and chloride ions, Cl–.
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Chapter 2 Section 1 Nature of Matter Ionic Bonding
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Chapter 2 Objectives Analyze the properties of water.
Section 2 Water and Solutions Objectives Analyze the properties of water. Describe how water dissolves substances. Distinguish between acids and bases.
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Chapter 2 Water in Living Things Storage of Energy
Section 2 Water and Solutions Water in Living Things Storage of Energy Many organisms release excess heat through water evaporation. In organisms, this ability to control temperature enables cells to maintain a constant internal temperature when the external temperature changes. In this way, water helps cells maintain homeostasis.
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Water in Living Things, continued
Chapter 2 Section 2 Water and Solutions Water in Living Things, continued Cohesion and Adhesion Cohesion is an attraction between substances of the same kind. Because of cohesion, water and other liquids form thin films and drops. Molecules at the surface of water are linked together by hydrogen bonds like a crowd of people linked by holding hands. This attraction between water molecules causes a condition known as surface tension.
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Water in Living Things, continued
Chapter 2 Section 2 Water and Solutions Water in Living Things, continued Cohesion and Adhesion Adhesion is an attraction between different substances. Adhesion powers a process, called capillary action, in which water molecules move upward through a narrow tube, such as the stem of a plant.
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Comparing Cohesion and Adhesion
Chapter 2 Section 2 Water and Solutions Comparing Cohesion and Adhesion
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Chapter 2 Aqueous Solutions
Section 2 Water and Solutions Aqueous Solutions A solution is a mixture in which one or more substances are evenly distributed in another substance. Many important substances in the body have been dissolved in blood or other aqueous fluids. Because these substances can dissolve in water, they can more easily move within and between cells.
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Solutes, Solvents and Solutions
Chapter 2 Section 2 Water and Solutions Solutes, Solvents and Solutions
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Aqueous Solutions, continued
Chapter 2 Section 2 Water and Solutions Aqueous Solutions, continued Polarity The polarity of water enables many substances to dissolve in water. When ionic compounds are dissolved in water, the ions become surrounded by polar water molecules. The resulting solution is a mixture of water molecules and ions.
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Aqueous Solutions, continued
Chapter 2 Section 2 Water and Solutions Aqueous Solutions, continued Polarity When sodium chloride, NaCl, is dissolved in water, sodium ions, Na+, and chloride ions, Cl–, become surrounded by water molecules, H2O.
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Aqueous Solutions, continued
Chapter 2 Section 2 Water and Solutions Aqueous Solutions, continued Polarity Nonpolar molecules do not dissolve well in water. The inability of nonpolar molecules to dissolve in polar molecules is important to organisms. For example, the shape and function of cell membranes depend on the interaction of polar water with nonpolar membrane molecules.
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Comparing Polar and Nonpolar Covalent Bonds
Chapter 2 Section 2 Water and Solutions Comparing Polar and Nonpolar Covalent Bonds
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Aqueous Solutions, continued
Chapter 2 Section 2 Water and Solutions Aqueous Solutions, continued Acids and Bases Compounds that form hydrogen ions when dissolved in water are called acids. When an acid is added to water, the concentration of hydrogen ions in the solution is increased above that of pure water.
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Chapter 2 Section 2 Water and Solutions Acids
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Aqueous Solutions, continued
Chapter 2 Section 2 Water and Solutions Aqueous Solutions, continued Acids and Bases Compounds that reduce the concentration of hydrogen ions in a solution are called bases. Many bases form hydroxide ions when dissolved in water.
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Chapter 2 Section 2 Water and Solutions Bases
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Aqueous Solutions, continued
Chapter 2 Section 2 Water and Solutions Aqueous Solutions, continued Acids and Bases The pH scale measures the concentration of hydrogen ions in a solution.
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Chapter 2 Section 2 Water and Solutions pH
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Chapter 2 Section 3 Chemistry of Cells Objectives Summarize the characteristics of organic compounds. Compare the structures and function of different types of biomolecules. Describe the components of DNA and RNA. State the main role of ATP in cells.
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Chapter 2 Carbon Compounds Carbohydrates
Section 3 Chemistry of Cells Carbon Compounds Carbohydrates Carbohydrates are organic compounds made of carbon, hydrogen, and oxygen atoms in the proportion of 1:2:1. Carbohydrates are a key source of energy, and they are found in most foods—especially fruits, vegetables, and grains.
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Chapter 2 Section 3 Chemistry of Cells Carbohydrates
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Carbon Compounds, continued
Chapter 2 Section 3 Chemistry of Cells Carbon Compounds, continued Carbohydrates The building blocks of carbohydrates are single sugars, called monosaccharides, such as glucose, C6H12O6, and fructose. Simple sugars such as glucose are a major source of energy in cells.
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Chapter 2 Section 3 Chemistry of Cells Monosaccharides
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Carbon Compounds, continued
Chapter 2 Section 3 Chemistry of Cells Carbon Compounds, continued Carbohydrates Disaccharides are double sugars formed when two monosaccharides are joined. Sucrose, or common table sugar, is a disaccharide that consists of both glucose and fructose.
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Chapter 2 Section 3 Chemistry of Cells Disaccharides
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Carbon Compounds, continued
Chapter 2 Section 3 Chemistry of Cells Carbon Compounds, continued Carbohydrates Polysaccharides such as starch, shown below, are chains of three or more monosaccharides.
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Carbon Compounds, continued
Chapter 2 Section 3 Chemistry of Cells Carbon Compounds, continued Lipids Lipids are nonpolar molecules that are not soluble in water. They include fats, phospholipids, steroids, and waxes. Fats are lipids that store energy. A typical fat contains three fatty acids bonded to a glycerol molecule backbone.
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Chapter 2 Section 3 Chemistry of Cells Types of Lipids
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Chapter 2 Section 3 Chemistry of Cells Fats
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Carbon Compounds, continued
Chapter 2 Section 3 Chemistry of Cells Carbon Compounds, continued Lipids In a saturated fatty acid, all of the carbon atoms in the chain are bonded to two hydrogen atoms (except the carbon atom on the end, which is bonded to three hydrogen atoms). In an unsaturated fatty acid, some of the carbon atoms are linked by a “double” covalent bond, each with only one hydrogen atom, producing kinks in the molecule.
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Saturated and Unsaturated Fatty Acids
Chapter 2 Section 3 Chemistry of Cells Saturated and Unsaturated Fatty Acids
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Chapter 2 Section 3 Chemistry of Cells Fatty Acids
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Carbon Compounds, continued
Chapter 2 Section 3 Chemistry of Cells Carbon Compounds, continued Proteins A protein is a large molecule formed by linked smaller molecules called amino acids. Amino acids are the building blocks of proteins. Twenty different amino acids are found in proteins.
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Chapter 2 Section 3 Chemistry of Cells Structure of Proteins
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Chapter 2 Section 3 Chemistry of Cells Proteins
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Chapter 2 Section 3 Chemistry of Cells Amino Acids
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Carbon Compounds, continued
Chapter 2 Section 3 Chemistry of Cells Carbon Compounds, continued Nucleic Acids A nucleic acid is a long chain of smaller molecules called nucleotides. A nucleotide has three parts: a sugar, a base, and a phosphate group, which contains phosphorus and oxygen atoms.
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Chapter 2 Section 3 Chemistry of Cells Nucleic Acid
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Chapter 2 Section 3 Chemistry of Cells Nucleotide
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Carbon Compounds, continued
Chapter 2 Section 3 Chemistry of Cells Carbon Compounds, continued Nucleic Acids There are two types of nucleic acids—DNA and RNA—and each type contains four kinds of nucleotides. DNA, or deoxyribonucleic acid, consists of two strands of nucleotides that spiral around each other. RNA, or ribonucleic acid, consists of a single strand of nucleotides.
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Structure of Nucleic Acids
Chapter 2 Section 3 Chemistry of Cells Structure of Nucleic Acids
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Chapter 2 Section 3 Chemistry of Cells DNA Overview
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Ribonucleic Acid (RNA)
Chapter 2 Section 3 Chemistry of Cells Ribonucleic Acid (RNA)
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Carbon Compounds, continued
Chapter 2 Section 3 Chemistry of Cells Carbon Compounds, continued ATP ATP or adenosine triphosphate, is a single nucleotide with two extra energy-storing phosphate groups. When food molecules are broken down inside cells, some of the energy in the molecules is stored temporarily in ATP.
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Chapter 2 Section 3 Chemistry of Cells Comparing ADP and ATP
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Section 4 Energy and Chemical Reactions
Chapter 2 Objectives Evaluate the importance of energy to living things. Relate energy and chemical reactions. Describe the role of enzymes in chemical reactions. Identify the effect of enzymes on food molecules.
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Energy for Life Processes
Section 4 Energy and Chemical Reactions Chapter 2 Energy for Life Processes Energy is the ability to move or change matter. Energy exists in many forms—including light, heat, chemical energy, mechanical energy, and electrical energy—and it can be converted from one form to another. Energy can be stored or released by chemical reactions.
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Section 4 Energy and Chemical Reactions
Chapter 2 Energy
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Energy for Life Processes, continued
Section 4 Energy and Chemical Reactions Chapter 2 Energy for Life Processes, continued Energy in Chemical Reactions In chemical reactions, energy is absorbed or released when chemical bonds are broken and new ones are formed. Metabolism is the term used to describe all of the chemical reactions that occur within an organism.
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Energy and Chemical Reactions
Section 4 Energy and Chemical Reactions Chapter 2 Energy and Chemical Reactions
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Energy for Life Processes, continued
Section 4 Energy and Chemical Reactions Chapter 2 Energy for Life Processes, continued Activation Energy The energy needed to start a chemical reaction is called activation energy. Activation energy is simply a chemical “push” that starts a chemical reaction. Even in a chemical reaction that releases energy, activation energy must be supplied before the reaction can occur.
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Activation Energy and Chemical Reactions
Section 4 Energy and Chemical Reactions Chapter 2 Activation Energy and Chemical Reactions
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Section 4 Energy and Chemical Reactions
Chapter 2 Enzymes Enzymes are substances that increase the speed of chemical reactions. Most enzymes are proteins. Enzymes are catalysts, which are substances that reduce the activation energy of a chemical reaction.
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Chapter 2 Enzymes, continued
Section 4 Energy and Chemical Reactions Chapter 2 Enzymes, continued An enzyme increases the speed of a chemical reaction by reducing the activation energy of the reaction.
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Section 4 Energy and Chemical Reactions
Chapter 2 Enzyme
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Chapter 2 Enzymes, continued Enzyme Specificity
Section 4 Energy and Chemical Reactions Chapter 2 Enzymes, continued Enzyme Specificity A substance on which an enzyme acts during a chemical reaction is called a substrate. Enzymes act only on specific substrates. An enzyme’s shape determines its activity. Typically, an enzyme is a large protein with one or more deep folds on its surface. These folds form pockets called active sites.
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Chapter 2 Enzymes, continued Enzyme Specificity
Section 4 Energy and Chemical Reactions Chapter 2 Enzymes, continued Enzyme Specificity An enzyme acts only on a specific substrate because only that substrate fits into its active site. Step 1 When an enzyme first attaches to a substrate, the enzyme’s shape changes slightly. Step 2 At an active site, an enzyme and a substrate interact, reducing the reaction’s activation energy. Step 3 The reaction is complete when products have formed.
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Section 4 Energy and Chemical Reactions
Chapter 2 Enzyme Activity
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Chapter 2 Enzymes, continued Factors in Enzyme Activity
Section 4 Energy and Chemical Reactions Chapter 2 Enzymes, continued Factors in Enzyme Activity Any factor that changes the shape of an enzyme can affect the enzyme’s activity. Temperature and pH value can alter an enzymes effectiveness. The enzymes that are active at any one time in a cell determine what happens in that cell.
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Factors Affecting Reaction Rate
Section 4 Energy and Chemical Reactions Chapter 2 Factors Affecting Reaction Rate
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Chapter 2 Multiple Choice
Standardized Test Prep Multiple Choice Use the figure below to answer questions 1–3.
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Multiple Choice, continued
Chapter 2 Standardized Test Prep Multiple Choice, continued 1. The molecule shown in the diagram is A. cellulose B. DNA C. RNA D. ATP
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Multiple Choice, continued
Chapter 2 Standardized Test Prep Multiple Choice, continued 1. The molecule shown in the diagram is A. cellulose B. DNA C. RNA D. ATP
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Multiple Choice, continued
Chapter 2 Standardized Test Prep Multiple Choice, continued 2. What is the main function of this molecule? F. promoting chemical reactions G. making up cell membranes H. storing energy J. storing hereditary information
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Multiple Choice, continued
Chapter 2 Standardized Test Prep Multiple Choice, continued 2. What is the main function of this molecule? F. promoting chemical reactions G. making up cell membranes H. storing energy J. storing hereditary information
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Multiple Choice, continued
Chapter 2 Standardized Test Prep Multiple Choice, continued 3. What do the dashed lines in the drawing represent? A. nuclear bonds B. covalent bonds C. hydrogen bonds D. ionic bonds
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Multiple Choice, continued
Chapter 2 Standardized Test Prep Multiple Choice, continued 3. What do the dashed lines in the drawing represent? A. nuclear bonds B. covalent bonds C. hydrogen bonds D. ionic bonds
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