Chapter 6 Chemistry in Biology

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Chemistry in BiologyChapter 6

88Chemistry in BiologyChapter 6



91ElementsChemistry in BiologyAn element is a pure substance that cannot be broken down into other substances by physical or chemical means.There are over 100 known elements, 92 of which occur naturally.Each element has a unique name and symbol.

6.1 Atoms, Elements, and CompoundsChapter 65The Periodic Table of ElementsChemistry in BiologyHorizontal rows are called periods.Vertical columns are called groups.

6.1 Atoms, Elements, and CompoundsChapter 66Chemistry in BiologyGlencoe Biology Transparencies

Chapter 6

80Chemistry in BiologyImage BankChapter 6

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atomnucleusprotonneutronelectronelementisotopecompoundcovalent bondmoleculeionionic bondvan der Waals force

Chemistry in BiologyVocabularySection 1Chapter 683Ionic BondsEnzymesVisualizing Properties of WaterPolypeptidesChemistry in BiologyAnimationChapter 6

87Chemistry in BiologyChapter Resource Menu

Chapter Diagnostic QuestionsFormative Test QuestionsChapter Assessment QuestionsStandardized Test Practicebiologygmh.comGlencoe Biology TransparenciesImage BankVocabularyAnimation

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48Chapter 6 Chemistry in BiologySection 1: Atoms, Elements, and CompoundsSection 2: Chemical ReactionsSection 3: Water and SolutionsSection 4: The Building Blocks of LifeClick on a lesson name to select.2Chemistry in BiologyThe elements identified as metals tend to donate electrons.The elements identified as nonmetals tend to accept electrons.6.1 Atoms, Elements, and CompoundsChapter 6Some atoms tend to donate or accept electrons more easily than other atoms.13Most ionic compounds are crystalline at room temperature and have higher melting points than molecular compounds formed by covalent bonds.Chemistry in Biology6.1 Atoms, Elements, and CompoundsChapter 614Chemistry in Biologyvan der Waals ForcesWhen molecules come close together, the attractive forces between slightly positive and negative regions pull on the molecules and hold them together.The strength of the attraction depends on the size of the molecule, its shape, and its ability to attract electrons.

6.1 Atoms, Elements, and CompoundsChapter 615Chemical EquationsChemistry in Biology

Chemical formulas describe the substances in the reaction and arrows indicate the process of change.Reactants are the starting substances, on the left side of the arrow.Products are the substances formed during the reaction, on the right side of the arrow.

6.2 Chemical ReactionsChapter 617

Glucose and oxygen react to form carbon dioxide and water.Chemistry in Biology6.2 Chemical ReactionsChapter 618Chemistry in BiologyBalanced EquationsThe law of conservation of mass states matter cannot be created or destroyed.The number of atoms of each element on the reactant side must equal the number of atoms of the same element on the product side.

6.2 Chemical ReactionsChapter 619Chemistry in BiologyThe activation energy is the minimum amount of energy needed for reactants to form products in a chemical reaction.

Energy of Reactions6.2 Chemical ReactionsChapter 620Chemistry in Biology

This reaction is exothermic and released heat energy.The energy of the product is lower than the energy of the reactants.6.2 Chemical ReactionsChapter 621Chemistry in Biology

This reaction is endothermic and absorbed heat energy.The energy of the products is higher than the energy of the reactants.6.2 Chemical ReactionsChapter 622Chemistry in BiologyA catalyst is a substance that lowers the activation energy needed to start a chemical reaction.Enzymes are biological catalysts.

It does not increase howmuch product is made and it does not get used up in the reaction.Enzymes

6.2 Chemical ReactionsChapter 623Chemistry in BiologyThe reactants that bind to the enzyme are called substrates.The specific location where a substrate binds on an enzyme is called the active site.

6.2 Chemical ReactionsChapter 624Chemistry in BiologyFactors such as pH, temperature, and other substances affect enzyme activity.6.2 Chemical ReactionsChapter 6The active site changes shape and forms the enzyme-substrate complex, which helps chemical bonds in the reactants to be broken and new bonds to form.25Chemistry in BiologyChapter 6

26Chemistry in Biology

6.3 Water and SolutionsChapter 6

Enzyme-Controlled Reactions28Chemistry in BiologyChapter 6

29Chemistry in BiologyHomogenous MixturesA mixture that has a uniform composition throughoutA solvent is a substance in which another substance is dissolved.A solute is the substance that is dissolved in the solvent.

Food coloring dissolved in water forms a homogenous mixture.6.3 Water and SolutionsChapter 630Chemistry in BiologyHeterogeneous MixturesIn a heterogeneous mixture, the components remain distinct.

A salad is a heterogeneous mixture.6.3 Water and SolutionsChapter 631Chemistry in BiologySubstances that release hydrogen ions (H+) when dissolved in water are called acids.Substances that release hydroxide ions (OH) when dissolved in water are called bases.

Acids and Bases6.3 Water and SolutionsChapter 632Chemistry in BiologyThe measure of concentration of H+ in a solution is called pH.Acidic solutions have pH values lower than 7.

Basic solutions have pH values higher than 7.

pH and Buffers6.3 Water and SolutionsChapter 633Chemistry in BiologyBuffers are mixtures that can react with acids or bases to keep the pH within a particular range.

6.3 Water and SolutionsChapter 634Carbon has four electrons in its outermost energy level.One carbon atom can form four covalent bonds with other atoms.Chemistry in BiologyCarbon compounds can be in the shape of straight chains, branched chains, and rings.

6.4 The Building Blocks of LifeChapter 636MacromoleculesChemistry in BiologyCarbon atoms can be joined to form carbon molecules.Macromolecules are large molecules formed by joining smaller organic molecules together.Polymers are molecules made from repeating units of identical or nearly identical compounds linked together by a series of covalent bonds.

6.4 The Building Blocks of LifeChapter 637Chemistry in BiologyChapter 6

38Chemistry in BiologyCarbohydratesCompounds composed of carbon, hydrogen, and oxygen in a ratio of one oxygen and two hydrogen atoms for each carbon atom(CH2O)n

6.4 The Building Blocks of LifeChapter 639Chemistry in BiologyTwo monosaccharides joined together form a disaccharide.Longer carbohydrate molecules are called polysaccharides. 6.4 The Building Blocks of LifeChapter 6Values of n ranging from three to seven are called simple sugars, or monosaccharides.40Chemistry in BiologyLipidsMolecules made mostly of carbon and hydrogenA triglyceride is a fat if it is solid at room temperature and an oil if it is liquid at room temperature.

6.4 The Building Blocks of LifeChapter 641Chemistry in BiologyLipids that have tail chains with only single bonds between the carbon atoms are called saturated fats.Lipids that have at least one double bond between carbon atoms in the tail chain are called unsaturated fats.Fats with more than one double bond in the tail are called polyunsaturated fats.6.4 The Building Blocks of LifeChapter 642Chemistry in BiologyProteinsA compound made of small carbon compounds called amino acidsAmino acids are small compounds that are made of carbon, nitrogen, oxygen, hydrogen, and sometimes sulfur.

6.4 The Building Blocks of LifeChapter 643

Chemistry in BiologyAmino acids have a central carbon atom.One of the four carbon bonds is with hydrogen.The other three bonds are with an amino group (NH2), a carboxyl group (COOH), and a variable group (R).6.4 The Building Blocks of LifeChapter 644Chemistry in BiologyChapter 6

45Chemistry in BiologyThe number and the order in which the amino acids are joined define the proteins primary structure.After an amino acid chain is formed, it folds into a unique three-dimensional shape, which is the proteins secondary structure, such as a helix or a pleat.

6.4 The Building Blocks of LifeChapter 646Chemistry in BiologyNucleic acids are complex macromolecules that store and transmit genetic information.Nucleic acids are made of smaller repeating subunits called nucleotides, composed of carbon, nitrogen, oxygen, phosphorus, and hydrogen atoms.

6.4 The Building Blocks of LifeChapter 6

47ABCD

CDQ 2

Chemistry in BiologyChapter Diagnostic QuestionsChapter 6

electrons neutrons protons ionsIsotopes are created by a change in the number of what particle of an atom?50ABCD

CDQ 3

Chemistry in BiologyChapter Diagnostic QuestionsChapter 6

substrates enzymes ions reactantsIdentify the proteins that speed up the rate of chemical reactions.51ABC

FQ 2Chemistry in BiologyChapter 6

6.1 Formative Questions

an equal number of protons and neutrons an equal number of protons and electrons an equal number of neutrons and electronsWhat causes the overall charge of an atom to be zero?53ABCD


6.1 Formative Questions a compound an element an isotope a mixtureWhat type of substance is water?

54ABCD


6.1 Formative Questions chemical bonds ionic compounds radioactive isotopes van der Waals forcesWhat provides the energy for all living processes?

55ABCD


6.2 Formative Questions a match burning salt dissolving water boiling gasoline evaporatingWhich is a chemical reaction?

56AB


6.2 Formative QuestionsWhich chemical reaction is endothermic?

57ABCD


6.2 Formative Questions It acts as a reactant. It reduces the amount of heat produced. It increases the amount of product. It lowers the activation energy.How does an enzyme increase the rate of a chemical reaction?

58ABCD



What occurs at the active site in the enzyme substrate complex?

An exothermic chemical reaction takes place. Chemical bonds are broken and new bonds are formed. The enzyme gets used up in the reaction. The substrates provide energy for the enzyme.59ABCD



It acts as a catalyst. Its pH is neutral. It is a polar molecule. It is an ionic compound.Why is water able to dissolve a wide variety of solutes?60ABCD



covalent bonds double bonds hydrogen bonds ionic bondsWhat type of bonds attracts water molecules to each other and to other substances? 61ABCD



Cl OH H+ Na+Which ion, when released in water, causes a solution to be basic?62ABCD



alkali antacid buffer neutralizerWhat is the name for a substance that keeps the pH in cells within the 6.5 to 7.5 pH range?63ABCD



carbon nitrogen phosphorus sodiumWhich element do almost all biological molecules contain?64ABCD



1 2 4 8How many covalent bonds can carbon form with other atoms?

65ABCD



hormone nucleic acid protein steroidWhat type of biological molecule is an enzyme?66ABCD



lipids nucleotides polypeptides sugarsWhat are fats, oils, and waxes composed of?67ABCD



amino acids fatty acids glycerols nucleotidesWhat are the monomers that make up proteins?68ABCD


carbohydrate lipid nucleic acid proteinWhich biological molecule transports substances between cells?6.4 Formative Questions69ABCD

CAQ 2Chemistry in BiologyChapter 6

Chapter Assessment Questions 2 4 6 8Look at the energy levels in the atom. What is the maximum number of electrons energy level two can hold?

71Explain why chemical equations must be balanced. Chemistry in BiologyAnswer: Chemical reactions require balanceof mass. Therefore, the number of atoms of each element on the reactant side must equal the number of atoms of the same element on the product side.Chapter Assessment QuestionsChapter 6

CAQ 372ABCD

STP 2Chemistry in BiologyChapter 6

What is true of this chemical reaction?

Energy is not needed to start the chemical reaction. Heat and/or light energy are released in this reaction. The activation energy is greater than the energy released. The energy of the products and the reactants is the same.Standardized Test Practice74ABCD


Standardized Test Practice tomatoes bananasWhich fruit contains a higher concentration of hydrogen ions?

75ABCD


Standardized Test PracticeWhat do cellulose and chitin have in common? They are energy- storing polymers. They are found in the cells of animals. They are structural polysaccharides. They are composed of repeating sucrose units.76ABCD


Standardized Test Practice gluten glycogen starch sucroloseWhich polysaccharide stores energy in muscle and liver tissue?77ABCD


Standardized Test PracticeWhat is the function of this biological macromolecule?

communicate signals between cells produce vitamins and hormones provide support and protection store and transmit genetic information78ABCD


Standardized Test PracticeWhich is a characteristic of all lipids? They are saturated triglycerides. They do not dissolve in water. They are liquid at room temperature. They store less energy than carbohydrates.79Chemistry in Biology

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chemical reactionreactantproductactivation energycatalystenzymesubstrateactive siteChemistry in BiologyVocabularySection 2Chapter 684

polar moleculehydrogen bondmixturesolutionsolventsoluteacidbasepHbufferChemistry in BiologyVocabularySection 3Chapter 685

macromoleculepolymercarbohydratelipidproteinamino acidnucleic acidnucleotideChemistry in BiologyVocabularySection 4Chapter 686

Chapter 6 Chemistry in Biology

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