2 2.1? Identify the three subatomic Particles found in atoms Explain how all the isotopes of an element are similar and how they are different Explain how compounds are different from their component elements Describe the two main types of chemical bonds. Indiana Standards covered: NoS.6
3 THINK ABOUT IT What are you made of? Just as buildings are made from bricks, steel, glass, and wood, living things are made from. Chemical Compounds When you breathe, eat, or drink, your body uses the substances in air, food, and water to carry out Chemical Reactions that keep you alive. Chemistry The first job of a biologist is to understand the of life.
4 Atoms What three subatomic particles make up atoms?
5 Atoms What three subatomic particles make up atoms? Protons The subatomic particles that make up atoms are,, and. Neutrons Electrons
6 Atoms The study of chemistry begins with the, the atom. Atom basic unit of matter The concept of the came first from the Greek philosopher Democritus, nearly 2500 years ago. Democritus asked, can you divide a substance without limit, or does there come a point at which you cannot divide the substance without changing it into something else? Democritus thought that there had to be a limit, and he called the smallest fragment the atom, from the Greek word atomos, which means unable to be cut.
7 Atoms incredibly small Atoms are. Placed side by side, 100 million atoms would make a row only about 1 centimeter long about the width of your little finger! Despite its extremely small size, an atom contains that are even smaller. subatomic particles The subatomic particles that make up atoms are, Protons, and. Neutrons Electrons The subatomic particles in a carbon atom are shown.
8 Protons and Neutrons Protons and neutrons have about the. Mass Positively Protons are charged particles (+) and neutrons carry No Charge at all. Bind Strong forces protons and neutrons together to form the nucleus, at the center of the atom.
9 Electrons The electron is a particle ( ) with only 1/1840 the mass of a proton. negatively charged Electrons are in constant motion in the space surrounding the nucleus. They are attracted to the positively charged nucleus but remain outside the nucleus because of the. energy of their motion
10 Electrons Because atoms have of equal numbers electrons and protons, their positive and negative charges balance out, and atoms themselves are electrically. neutral The carbon atom shown has 6 and 6. protons electrons
11 Elements and Isotopes How are all of the isotopes of an element similar?
12 Elements and Isotopes How are all of the isotopes of an element similar? Number of electrons Because they have the same, all isotopes of an element have the same. Chemical properties
13 Elements and Isotopes A chemical element is that A pure substance consists entirely of. One type of atom More than 100 elements are known, but only about two dozen are commonly found. Living organisms Elements are represented by one- or twoletter symbols. For example, C stands for carbon, H for hydrogen, Na for sodium, and Hg for mercury (shown).
14 Elements and Isotopes Number of protons The in the nucleus of an element is called its. Atomic number Carbon s atomic number is 6, meaning that each atom of carbon has six protons and, consequently, six electrons.
15 Isotopes different Atoms of an element may have numbers of. neutrons For example, although all atoms of carbon have six protons, some have six neutrons, some seven, and a few have eight. Atoms of the same element that differ in the number of neutrons they contain are known as. isotopes
16 Isotopes protons neutrons The total number of and in the nucleus of an atom is called its. mass number are isotopes identified by their mass numbers; for example, carbon-12, carbon-13, and carbon-14.
17 Isotopes Weighted average of masses The of an element s isotopes, in which the abundance of each isotope in nature is considered, is called its. atomic mass same number of electrons Because they have the, all isotopes of an element have the same chemical properties.
18 Radioactive Isotopes radioactive Some isotopes are, meaning that their and nuclei are unstable break down at a constant rate over time. Although radiation can be dangerous, radioactive isotopes have a number of. scientific and practical uses Geologists can determine the ages of rocks and fossils by analyzing the isotopes found in them. Radiation from certain isotopes can be used to detect and treat cancer and to kill bacteria that cause food to spoil. Radioactive isotopes can also be used as labels or tracers to follow the movements of substances within organisms.
19 Chemical Compounds In what ways do compounds differ from their component elements?
20 Chemical Compounds In what ways do compounds differ from their component elements? physical chemical compound The and properties of a are usually very different from those of the elements from which it is formed.
21 Chemical Compounds compound two or more A chemical is a substance formed by the chemical combination of elements in definite proportions. The composition of compounds Scientists show by a kind of shorthand known as a. chemical formula Water, which contains two atoms of hydrogen for each atom of oxygen, has the chemical formula H 2 O. The formula for table salt, NaCl, indicates that the elements that make up table salt sodium and chlorine combine in a 1:1 ratio.
22 Chemical Compounds The physical and chemical properties of a compound are usually very different from those of the elements from which it is formed. For example, sodium is a silver-colored metal that is soft enough to cut with a knife. It reacts explosively with cold water. Chlorine is a very reactive, poisonous, greenish gas that was used in battles during World War I. However, the compound sodium chloride--table salt--is a white solid that dissolves easily in water, is not poisonous, and is essential for the survival of most living things.
23 Chemical Bonds What are the main types of chemical bonds?
24 Chemical Bonds What are the main types of chemical bonds? ionic bonds The main types of chemical bonds are and. covalent bonds
25 Chemical Bonds The atoms in compounds are held together by various types of. chemical bonds electrons Bond formation involves the that surround each. atomic nucleus The electrons that are available to form bonds are called. valence electrons The main types of chemical bonds are ionic bonds and covalent bonds.
26 Ionic Bonds one or more electrons An ionic bond is formed when are transferred from one atom to another. loses An atom that electrons becomes positively charged. An atom that gains electrons has a negative charge. These positively and negatively charged atoms are known as. ions
27 Ionic Bonds Ionic bonds form between sodium and chlorine to form NaCl, table salt.
28 Ionic Bonds A sodium atom easily loses its one valence electron and becomes a sodium ion (Na + ).
29 Ionic Bonds A chlorine atom an gains electron (from sodium) and becomes a chloride ion (Cl - ).
30 Ionic Bonds These oppositely charged ions have a strong attraction for each other, forming an ionic bond.
31 Covalent Bonds shared Sometimes electrons are by atoms instead of being transferred. The moving electrons travel about the nuclei of both atoms, forming a. covalent bond single When the atoms share two electrons, the bond is called a covalent bond. Sometimes the atoms share four electrons and form a double bond. In a few cases, atoms can share six electrons, forming a bond. triple
32 Covalent Bonds The structure that results when atoms are joined together by covalent bonds is called a molecule, the smallest unit of most compounds. This diagram of a water molecule shows that each hydrogen atom is joined to water s lone oxygen atom by a single covalent bond. Each hydrogen atom shares two electrons with the oxygen atom.
33 Covalent Bonds same element When atoms of the join together, they also form a molecule. Oxygen molecules in the air you breathe consist of two oxygen atoms joined by covalent bonds.
34 Van der Waals Forces Because of their structures, atoms of different elements do not all have the same ability. to attract electrons Some atoms have a stronger attraction for electrons than do other atoms. When the atoms in a covalent bond share electrons, the sharing is not. equal Even when the sharing is equal, the rapid movement of electrons can create regions on a molecule that have a tiny. positive or negative charge
35 Van der Waals Forces close together When molecules are, a slight attraction can develop between the oppositely charged regions of nearby molecules. These intermolecular forces of attraction are called, Van der Waals forces after the scientist who discovered them. Although van der Waals forces are not as strong as ionic bonds or covalent bonds, they can hold molecules together, especially when the. molecules are large
36 Assessment An atom of calcium has 20 protons. How many electrons does it have? 20 electrons
37 Assessment Compare the isotopes carbon-12 and carbon-14. How are they similar and how are they different? They have the same number of protons and electrons. Carbon-12 has 12 neutrons. Carbon- 14 has 14 neutrons.
38 Assessment A potassium atom can easily lose 1 electron. What kind of bond will potassium form with chlorine? An ionic bond
39 Lesson Overview 2.2 Properties of Water
40 2.2 Properties of Water Discuss the unique properties of water Differentiate between solutions and suspensions Explain what acidic solutions and basic solutions are. Indiana Standards covered: NoS.6
41 THINK ABOUT IT Looking back at Earth from space, an astronaut called it the blue planet, referring to the oceans of water that cover nearly of three fourths Earth s surface. The very presence of liquid water tells a scientist that life may also be present on such a planet. Why should life itself be connected so strongly to something so ordinary that we often take it for granted? There is something very special about water and the role it plays in living things.
42 The Water Molecule How does the structure of water contribute to its unique properties?
43 The Water Molecule How does the structure of water contribute to its unique properties? polar molecule Because water is a, it is able to form multiple, hydrogen bonds which account for many of water s special properties.
44 The Water Molecule Water is one of the few compounds found in a over most of Earth s surface. neutral liquid state Like other molecules, water (H 2 O) is. The positive charges on its 10 protons balance out the negative charges on its 10 electrons.
45 Polarity Because of the angles of its chemical bonds, the atom oxygen is on one end of the molecule and the hydrogen atoms are on the other. With 8 protons in its nucleus, an oxygen atom has a much stronger attraction for electrons than does a hydrogen atom with its single proton.
46 Polarity There is a greater probability of finding the shared electrons in water close to its oxygen atom than near its. hydrogen atoms As a result, the oxygen end of the molecule has a slight negative charge and the hydrogen end of the molecule has a. slight positive charge
47 Polarity A molecule in which the charges are unevenly distributed is said to be polar, because the molecule is a bit like a magnet with two poles. The charges on a polar molecule are written in parentheses, ( ) or (+), to show that they are weaker than the charges on ions such as Na + and Cl.
48 Hydrogen Bonding Because of their partial positive and negative, charges polar molecules such as water can attract each other. The attraction between a hydrogen atom on one water molecule and the oxygen atom on another is known as a. hydrogen bond
49 Hydrogen Bonding Water is able to form multiple, hydrogen bonds which account for many of its special properties. Hydrogen bonds are not as strong as, Ionic or covalent bonds and they can form in other compounds besides water.
50 Cohesion Cohesion is an attraction between Molecules of the same. substance Because a single water molecule may be involved in as many as four hydrogen bonds at the same time, water is extremely. cohesive
51 Cohesion Cohesion causes, Water molecules to be drawn together which is why drops of water form beads on a smooth surface. Surface tension Cohesion also produces, explaining why some insects and spiders can walk on a pond s surface.
52 Adhesion Adhesion is an attraction between. molecules of different substances The surface of water in a graduated cylinder dips slightly in the center, forming a curve called a meniscus, because the adhesion between water molecules and glass molecules is stronger than the cohesion between water molecules.
53 Adhesion Adhesion between water and glass also causes water to rise in a narrow tube against the force of gravity. This effect is called. capillary action Capillary action is one of the forces that draws water out of the roots of a plant and up into its stems and leaves. Cohesion holds the column of water together as it rises.
54 Heat Capacity Because of the multiple hydrogen bonds between water molecules, it takes to A large amount of heat energy cause those molecules to move faster and raise the temperature of the water. Water s heat capacity, the amount of heat energy required to increase its, is relatively high. temperature Large bodies of water, such as oceans and lakes, can absorb large amounts of heat with only small changes in temperature. This protects organisms living within from drastic changes in temperature. At the cellular level, water absorbs the, heat produced by cell processes regulating the temperature of the cell.
55 Solutions and Suspensions How does water s polarity influence its properties as a solvent?
56 Solutions and Suspensions How does water s polarity influence its properties as a solvent? Water s polarity gives it the ability to dissolve. both ionic compounds and other polar molecules
57 Solutions and Suspensions Water is not always pure; it is often found as part of a mixture. composed of two or more elements or compounds A mixture is that are physically mixed together but not chemically combined. Living things are in part composed of mixtures involving water. Two types of mixtures that can be made with water are. solutions and suspensions
58 Solutions If a crystal of table salt is placed in water, sodium and chloride ions on the surface of the crystal are attracted to the polar water molecules.
59 Solutions Ions break away from the crystal and are surrounded by water molecules. The ions gradually become dispersed in the water, forming a type of mixture called a solution.
60 Solutions All the components of a solution are evenly distributed throughout the solution. In a saltwater solution, table salt is the solute the. substance that is dissolved Water is the solvent the. substance in which the solute dissolves
61 Solutions Water s polarity gives it the ability to. Dissolve both ionic compounds and other polar molecules Water easily dissolves salts, sugars, minerals, gases, and even other solvents such as alcohol. When a given amount of water has dissolved all of the solute it can, the solution is said to be. saturated
62 Suspensions Some materials do not dissolve when placed in water, but. separate pieces so small that they do not settle out Such mixtures of water and nondissolved material are known as suspensions. Some of the most important biological fluids are both solutions and suspensions. Blood is mostly water. It contains many dissolved compounds, but also cells and other undissolved particles that remain in suspension as the blood moves through the body.
63 Acids, Bases, and ph Why is it important for cells to buffer solutions against rapid changes in ph?
64 Acids, Bases, and ph Why is it important for cells to buffer solutions against rapid changes in ph? Buffers dissolved in life s fluids play an important role in maintaining homeostasis in organisms.
65 Acids, Bases, and ph Water molecules sometimes split apart to form hydrogen ions and hydroxide ions. This reaction can be summarized by a chemical equation in which double arrows are used to show that the reaction can occur in either direction.
66 Acids, Bases, and ph pure water In, about 1 water molecule in 550 million splits to form ions in this way. Because the number of positive hydrogen ions produced is equal to the number of negative hydroxide ions produced, pure water is. neutral
67 The ph Scale Chemists devised a measurement system called the ph scale to. Indicate the concentration of H + ions in solution 0 to 14 The ph scale ranges from. At a ph of 7, the concentration of H + ions and OH ions is equal. Pure water has. a ph of 7
68 The ph Scale Solutions with a ph below 7 are called acidic because. they have more H + ions than OH ions The lower the ph, the greater the acidity. Solutions with a ph above 7 are called basic because. they have more OH ions than H + ions The higher the ph, the more basic the solution.
69 The ph Scale Each step on the ph scale represents a factor of 10. For example, a liter of a solution with a ph of 4 has 10 times as many H + ions as a liter of a solution with a ph of 5.
70 Acids Any compound that forms H + ions in solution An acid is. H + ions Acidic solutions contain higher concentrations of than pure water and have ph values below 7. Strong acids tend to have ph values that range from. 1 to 3 Hydrochloric acid (HCl) is a strong acid produced by the stomach to help digest food.
71 Bases base A is a compound that produces hydroxide (OH ) ions in solution. lower concentrations Basic, or alkaline, solutions contain of H + ions than pure water and have ph values above 7. Strong bases, such as the lye (commonly NaOH) used in soapmaking, tend to have ph values ranging from. 11 to 14
72 Buffers most cells in the human body The ph of the fluids within must generally be kept between 6.5 and 7.5 in order to maintain. homeostasis If the ph is lower or higher, it will affect the chemical reactions that take place within the cells. One of the ways that organisms control ph is through dissolved compounds called buffers, which are weak acids or bases that can react with to strong acids or bases prevent sharp, sudden changes in ph.
73 Buffers acid to an unbuffered solution Adding causes the ph of the unbuffered solution to drop. If the solution contains a buffer, however, adding the acid will cause only. a slight change in ph
74 Assessment What property of water allows it to form hydrogen bonds? It is polar. The slight positive charge on the hydrogen atom in one water molecule is attracted to the slight negative charge on the oxygen atom in another water molecule.
75 Assessment What is the difference between a solution and a suspension? A solution is a mixture of two or more substances in which the molecules of substances are evenly distributed. A suspension is a mixture of water and nondissolved materials.
76 Assessment During exercise many chemical changes happen in the body, including a drop in blood ph, which can be very serious. How is the body able to deal with such changes? A drop in blood ph is countered by chemical buffers such as bicarbonate and phosphate ions.
77 Lesson Overview 2.3 Carbon Compounds
78 2.3 Carbon Compounds Describe the unique qualities of carbon Describe the structures and functions of each of the four groups of macromolecules. Indiana Standards covered: NoS.3, NoS.6, B.1.1, B.1.2, B.5.1, B.5.4
79 THINK ABOUT IT In the early 1800s, many chemists called the compounds created by organisms organic, believing they were fundamentally different from compounds in nonliving things. We now understand that the principles governing the chemistry of living and nonliving things are the same, but the term organic chemistry is still around. Today, organic chemistry means the study of compounds that contain bonds between carbon atoms, while inorganic chemistry is the study of all other compounds.
80 The Chemistry of Carbon What elements does carbon bond with to make up life s molecules?
81 The Chemistry of Carbon What elements does carbon bond with to make up life s molecules? Carbon can bond with many elements, including hydrogen, oxygen, phosphorus, sulfur, and nitrogen to form. the molecules of life
82 The Chemistry of Carbon four valence electrons Carbon atoms have, allowing them to form strong covalent bonds with many other elements, including hydrogen, oxygen, phosphorus, sulfur, and nitrogen. Living organisms are made up of molecules that consist of. carbon and these other elements
83 The Chemistry of Carbon Carbon atoms can also bond to each other, which gives carbon the ability to form. Millions of different large and complex structures Carbon-carbon bonds can be single, double, or triple covalent bonds. Chains of carbon atoms can even. close upon themselves to form rings
84 Macromolecules What are the functions of each of the four groups of macromolecules?
85 Macromolecules What are the functions of each of the four groups of macromolecules? Living things use carbohydrates as. their main source of energy Plants, some animals, and other organisms also use carbohydrates for structural purposes.
86 Macromolecules What are the functions of each of the four groups of macromolecules? Lipids can be used to. store energy Some lipids are important parts of biological membranes and waterproof coverings.
87 Macromolecules What are the functions of each of the four groups of macromolecules? store Nucleic acids and transmit hereditary, or genetic, information.
88 Macromolecules What are the functions of each of the four groups of macromolecules? Some proteins control. the rate of reactions and regulate cell processes Others form important cellular structures, while still others transport substances into or out of cells or help to fight disease.
89 Macromolecules Many of the organic compounds in living cells are macromolecules, or made giant molecules from thousands or even hundreds of thousands of smaller molecules. Most macromolecules are formed by a process known as, polymerization in which large compounds are built by joining smaller ones together.
90 Macromolecules The smaller units, or monomers, join together to form polymers. The monomers in a polymer may be identical or different.
91 Macromolecules Biochemists sort the macromolecules found in living things into groups based on. their chemical composition The four major groups of macromolecules found in living things are. carbohydrates, lipids, nucleic acids, and proteins
92 Carbohydrates Carbohydrates are compounds made up of, atoms usually in a ratio of 1 : 2 : 1. carbon, hydrogen, and oxygen Living things use carbohydrates as. their main source of energy The breakdown of sugars, such as glucose, supplies immediate energy for. cell activities Plants, some animals, and other organisms also use carbohydrates for structural purposes.
93 Carbohydrates Many organisms store extra sugar as complex carbohydrates known as. starches The monomers in starch polymers are sugar molecules, such as glucose.
94 Simple Sugars Single sugar molecules are also known as monosaccharides. Besides glucose, monosaccharides include galactose,, which is a component of milk and fructose,. which is found in many fruits Ordinary table sugar, sucrose, is a disaccharide, a compound made by joining glucose and fructose together.
95 Complex Carbohydrates The large macromolecules formed from monosaccharides are known as polysaccharides.
96 Complex Carbohydrates Many animals store excess sugar in a polysaccharide called. glycogen When the level of glucose in your blood runs low,, glycogen is broken down into glucose which is then released into the blood. The glycogen stored in your muscles supplies. the energy for muscle contraction
97 Complex Carbohydrates Plants use a slightly different polysaccharide, called starch, to. store excess sugar cellulose Plants also make another important polysaccharide called, which gives plants much of their strength and rigidity.
98 Lipids Lipids are a large and varied group of biological molecules. Lipids are made and Mostly from carbon hydrogen atoms are generally. The common categories of lipids are. Lipids can be used to. Some lipids are important parts of biological membranes and waterproof coverings. Steroids not soluble in water store energy fats, oils, and waxes synthesized by the body are lipids as well. Many steroids, such as, serve as chemical messengers. hormones
99 Lipids Many lipids are formed when a glycerol molecule combines with compounds called fatty acids.
100 Lipids If each carbon atom in a lipid s fatty acid chains is joined to another carbon atom by a single bond, the lipid is. said to be saturated At least one carbon-carbon double bond If there is in a fatty acid, the fatty acid is said to be unsaturated. more than one double bond Lipids whose fatty acids contain are said to be polyunsaturated.
101 Lipids olive oil Lipids that contain unsaturated fatty acids, such as, tend to be liquid at room temperature. The data in the table illustrate how melting point decreases as the degree of unsaturation (number of double bonds) increases.
102 Nucleic Acids Nucleic acids store and transmit. hereditary, or genetic, information macromolecules Nucleic acids are containing hydrogen, oxygen, nitrogen, carbon, and phosphorus. Nucleic acids are polymers assembled from. Individual monomers known as nucleotides
103 Nucleic Acids Nucleotides consist of three parts: A 5-carbon sugar, a phosphate. group ( PO 4 ), and a nitrogenous base Some nucleotides, including adenosine triphosphate (ATP), play important roles in Capturing and transferring. chemical energy
104 Nucleic Acids Individual nucleotides can be joined by to covalent bonds form a polynucleotide, or nucleic acid. There are two kinds of nucleic acids: ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). RNA contains and the sugar ribose DNA contains. the sugar deoxyribose
105 Protein Proteins are macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen. amino acids Proteins are polymers of molecules called. Proteins perform many varied functions, such as controlling the rate of reactions and regulating cell processes,, Forming cellular structures transporting substances into or out of cells, and. helping to fight disease
106 Protein Amino acids are compounds with an amino group ( NH 2 ) on one end and a carboxyl group ( COOH) on the other end. Covalent bonds called peptide bonds. Link amino acids together to form a polypeptide A protein is a functional molecule built from one or more polypeptides.
107 Structure and Function amino acids All are identical in the amino and carboxyl groups. Any amino acid can be joined to any other amino acid by a peptide bond formed between these amino and carboxyl groups.
108 Structure and Function Amino acids differ from each other in a side chain called the R-group, which have a range of different properties. More than 20 different amino acids are found in nature. This variety results in proteins being. Among the most diverse macromolecules
109 Levels of Organization Proteins have four levels of structure. A protein s primary structure is. the sequence of its amino acids Secondary structure is Folding or coiling of polypeptide. chain
110 Levels of Organization Tertiary structure is the complete, three-dimensional arrangement of a polypeptide chain. Proteins with more than one chain have a fourth level of structure, which describes The way in which different polypeptide chains are arranged with respect to each other. For example, the protein shown, hemoglobin, consists of four subunits.
111 Assessment Why can carbon atoms form so many different structures? It has four valence electrons that it readily shares to become covalent bonds. Carbon can bond to the atoms of many other elements. Carbon can also readily bond to one another to form short chains, long chains, or rings, and these bonds can be single, double, or triple covalent bonds.
112 Assessment How do living things use lipids? Lipids can be used to store energy. Some lipids are important parts of biological membranes and waterproof coverings.
113 Assessment What are the four levels of organization in a protein? Primary structure is the sequence of its amino acids. Secondary structure is the folding or coiling of the polypeptide chain. Tertiary structure is the complete, 3-D arrangement of a polypeptide chain. Fourth level is one or more polypeptide chain.
114 Lesson Overview 2.4 Chemical Reactions and Enzymes
115 2.4 Chemical Reactions and Enzymes Explain how chemical reactions affect chemical bonds Describe how energy changes affect how easily a chemical reaction will occur Explain why enzymes are important to living things. Indiana Standards covered: NoS.6, B.1.1, B.1.2, B.1.3, B.5.4, B.5.5
116 THINK ABOUT IT Living things are made up of chemical compounds, but chemistry isn t just what life is made of chemistry is also what life does. Everything that happens in an organism its growth, its interaction with the environment, its reproduction, and even its movement is based on chemical reactions.
117 Chemical Reactions What happens to chemical bonds during chemical reactions?
118 Chemical Reactions What happens to chemical bonds during chemical reactions? Chemical reactions involve changes in the that chemical bonds join atoms in compounds.
119 Chemical Reactions A chemical reaction is a process that changes, or transforms, one set of chemicals into another by changing the chemical bonds that join atoms in compounds. Mass and energy are conserved during chemical transformations, including chemical reactions that occur in living organisms. enter into a chemical reaction The elements or compounds that are known as reactants. The elements or compounds produced by a chemical reaction are known as. products
120 Chemical Reactions An important chemical reaction in your bloodstream enables carbon dioxide to be removed from the body.
121 Chemical Reactions As it enters the blood, carbon dioxide (CO 2 ) reacts with water to produce carbonic acid (H 2 CO 3 ), which is highly soluble. This chemical reaction enables the blood to carry carbon dioxide to the lungs.
122 Chemical Reactions In the lungs, the reaction is reversed and produces carbon dioxide gas, which you exhale.
123 Energy in Reactions How do energy changes affect whether a chemical reaction will occur?
124 Energy in Reactions How do energy changes affect whether a chemical reaction will occur? release energy Chemical reactions that often occur on their own, or spontaneously. Chemical reactions that will absorb energy not occur without a source of energy.
125 Energy Changes Energy is released or absorbed whenever chemical bonds are formed or broken during chemical reactions. Energy changes are one of the most important factors in determining whether a chemical reaction will occur. Chemical reactions that release energy often occur on their own, or spontaneously Chemical reactions that absorb energy. will not occur without a source of energy
126 Energy Changes An example of an energy-releasing reaction is the burning of hydrogen gas, in which hydrogen reacts with oxygen to produce water vapor. The energy is released in the form of heat, and sometimes when hydrogen gas explodes light and sound.
127 Energy Changes The reverse reaction, in which water is changed into hydrogen and oxygen gas, absorbs so much energy that it generally doesn t occur by itself. 2H 2 O + energy 2 H 2 + O 2 The only practical way to reverse the reaction is to pass an electrical current through water to decompose water into hydrogen gas and oxygen gas. produces energy requires energy Thus, in one direction the reaction, and in the other direction the reaction.
128 Energy Sources source of energy Every organism must have a to carry out the chemical reactions it needs to stay alive. Plants get their energy by trapping and storing the energy from sunlight in energyrich compounds. Animals get their energy when they. consume plants or other animals Humans release the energy needed to grow, breathe, think, and even dream through the chemical reactions that occur when we, metabolize or break down, digested food.
129 Activation Energy release energy Chemical reactions that do not always occur spontaneously. is needed to get a reaction started The energy that is called the activation energy.
130 Activation Energy The peak of each graph represents the energy needed for the reaction to go forward. The difference between the required energy and the energy of the reactants is the activation energy. Activation energy is involved in chemical reactions whether or not the overall reaction. releases or absorbs energy
131 Enzymes What role do enzymes play in living things and what affects their function? speed up Enzymes chemical reactions that take place in cells. Temperature, ph, and regulatory molecules can affect the activity of enzymes.
132 Enzymes Some chemical reactions are Too slow or have activation energies that are too high to make them practical for living tissue. These chemical reactions are made possible by catalysts. A catalyst is a substance that. speeds up the rate of chemical reaction a reaction s activation energy Catalysts work by lowering.
133 Nature s Catalysts biological catalysts Enzymes are proteins that act as. They speed up chemical reactions that take place in cells. the activation energies Enzymes act by lowering, which has a dramatic effect on how quickly reactions are completed.
134 Nature s Catalysts For example, the reaction in which carbon dioxide combines with water to produce carbonic acid is so slow that carbon dioxide might build up in the body faster than the bloodstream could remove it. Your bloodstream contains an enzyme called carbonic anhydrase that speeds up the reaction by a factor of 10 million, so that the reaction takes place immediately and carbon dioxide is removed from the blood quickly.
135 Nature s Catalysts very specific only one Enzymes are, generally catalyzing chemical reaction. Part of an enzyme s name is usually derived from the reaction it catalyzes. Carbonic anhydrase gets its name because it also catalyzes the reverse reaction that removes water from carbonic acid.
136 The Enzyme-Substrate Complex For a chemical reaction to take place, the reactants must collide with enough energy so that existing bonds will be broken and new bonds will be. formed If the reactants do not have enough energy, they will. be unchanged after the collision Enzymes provide a site where reactants can. be brought together to react Such a site reduces the energy needed for reaction.
137 The Enzyme-Substrate Complex The reactants of enzymecatalyzed reactions are known as. substrates For example, the enzyme carbonic anhydrase converts the substrates carbon dioxide and water into carbonic acid (H 2 CO 3 ).
138 The Enzyme-Substrate Complex active site The substrates bind to a site on the enzyme called the. complementary shapes The active site and the substrates have. The fit is so precise that the active site and substrates are often compared to a. lock and key
139 Regulation of Enzyme Activity Temperature, ph, and regulatory molecules are all factors that can affect. the activity of enzymes Enzymes produced by human cells generally work best at temperatures close to 37 C,. the normal temperature of the human body certain ph values Enzymes work best at. For example, the stomach enzyme pepsin, which begins protein digestion, works best under. acidic conditions The activities of most enzymes are regulated by molecules that carry chemical signals within cells, switching enzymes on or off as needed.
140 Assessment A change in ph can change the shape of a protein. How might a change in ph affect the function of an enzyme? If a change in ph changes the shape of an enzyme it might result in the enzyme and substrates no longer fitting together properly. As a result, the enzyme would no longer be able to speed up the chemical reaction.
141 Assessment Describe the difference between a reaction that often happens on its own and one that does not. A reaction that occurs spontaneously releases energy. A reaction that does not occur spontaneously absorbs the energy.
142 Assessment What happens to chemical bonds during chemical reactions? The bonds change often they are formed or broken.
143 Assessment Why is the melting of ice not a chemical reaction? Because new chemicals are not formed.
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Name: Date: Per: Table # Elements & Macromolecules in rganisms Most common elements in living things are carbon, hydrogen, nitrogen, and oxygen. These four elements constitute about 95% of your body weight.
Elements & Macromolecules in rganisms Most common elements in living things are carbon, hydrogen, nitrogen, and oxygen. These four elements constitute about 95% of your body weight. All compounds can be
Basic chemistry for A level Biology Make a list of the missing words from the text please. Chose from this list; MISSING WORDS Neutrons, arrangement, carbon-14, charge, weak, alkaline, covalently, number,
CHAPTER 3 THE CHEMISTRY OF ORGANIC MOLECULES 3.1 Organic Molecules The chemistry of carbon accounts for the diversity of organic molecules found in living things. Carbon has six electrons, four of which
Biology 1 Elements & Macromolecules in rganisms Name Date our Most common elements in living things are carbon, hydrogen, nitrogen, and oxygen. These four elements constitute about 95% of your body weight.
Bio 100 Molecules of cells 1 Chapter 3 Molecules of Cells Compounds containing carbon are called organic compounds Molecules such as methane that are only composed of carbon and hydrogen are called hydrocarbons
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Name Biology 3 ID Number Lab 3 Organic Molecules of Biological Importance Section 1 - Organic Molecules Section 2 - Functional Groups Section 3 - From Building Blocks to Macromolecules Section 4 - Carbohydrates
NAME: BLK: Elements & Macromolecules in rganisms Most common elements in living things are carbon, hydrogen, nitrogen, and oxygen. These four elements constitute about 95% of your body weight. All compounds
Carbohydrates, Lipids, and Proteins 3.2 Organic vs. Inorganic compounds Organic compounds contain carbon and are found in living organisms Exceptions: hydrocarbonates, carbonates, oxides of carbon. Inorganic
Chemical Level of Organization Matter and Energy Matter occupies space and has mass Energy is capacity to move mass Potential vs. kinetic Energy forms radiant-moving waves electrical-moving charged particles
AP Biology Biology, Campbell and Reece, 10th Edition Adapted from chapter reading guides originally created by Lynn Miriello Name: Unit 1: Chemistry of Life Guided Reading Questions (70 pts total) Chapter
BIOLOGICAL MOLECULES OF LIFE C A R B O H Y D R A T E S, L I P I D S, P R O T E I N S, A N D N U C L E I C A C I D S The Academic Support Center @ Daytona State College (Science 115, Page 1 of 29) Carbon
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Cell Processes (chemistry and respiration) Organic compounds they always contain carbon 4 types that you need to know: Lipids (fats, oils and waxes), Carbohydrates, Proteins and nucleic acids Inorganic
The Molecules of Cells I. Introduction A. Most of the world s population cannot digest milk-based foods. 1. These people are lactose intolerant because they lack the enzyme lactase. 2. This illustrates
Chemistry is the science dealing with the properties & the transformations (chemical reactions) of all forms of matter Matter is any substance: solid, liquid, gas, plasma All matter is composed of elements
UNIT 1: Biochemistry 1.4: Carbohydrates and Lipids pg. 29 38 Carbohydrates Function, primary energy source for the cell, can also be a structural component of cells and organisms. Carbohydrates are the
Name: KEY Date: / / HR: Section 1 Chemistry of Life CHAPTER 3 CELL PROCESSES REVIEW 1. Define and give an example of the following: a. Atoms invisible particles that make up all mater; made from protons,
Biochemistry B.9.A compare the structures and functions of different types of biomolecules, including carbohydrates, lipids, proteins, and nucleic acids B.9.D analyze and evaluate the evidence regarding
ATOMS AND BONDS Atoms of elements are the simplest units of organization in the natural world. Atoms consist of protons (positive charge), neutrons (neutral charge) and electrons (negative charge). The
Name Period Concept 5.1 Macromolecules are polymers, built from monomers 1. The large molecules of all living things fall into just four main classes. Name them. 2. Circle the three classes that are called
The Chemical Level of Organization Objectives Describe atomic structure Compare the ways atoms combine to form molecules and compounds Distinguish among the major types of chemical reactions Describe the
the nature and importance of biomacromolecules in the chemistry of the cell: synthesis of biomacromolecules through the condensation reaction lipids and their sub-units; the role of lipids in the plasma
Chapter 2 - Chemical Foundations I. Introduction By weight, cells are about 70% water, about 1% ions, about 6% small organic molecules (including amino acids, sugars, nucleotides), and about 23% macromolecules.
Name Period Chapter 2: The Chemical Basis of Life Guided Reading Activities Big idea: Elements, atom, and compounds Answer the following questions as you read modules 2.1 2.4: 1. Match the following terms
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Chapter 5 Student Reading THE POLARITY OF THE WATER MOLECULE Wonderful water Water is an amazing substance. We drink it, cook and wash with it, swim and play in it, and use it for lots of other purposes.
Name: Date: Block: Molecular Modeling Background: In biology, the four most important elements found in living things are: H hydrogen (1 valence electron) O oxygen (2 valence electrons) N nitrogen (3 valence
Biological molecules: All are organic (based on carbon). Monomers vs. polymers: Monomers refer to the subunits that, when polymerized, make up a larger polymer. Monomers may function on their own in some
The Structure and Function of Large Biological Molecules by Dr. Ty C.M. Hoffman Slide 1 All of the biological macromolecules are built from smaller subunits. Each subunit features - H and - OH substituents
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Keystone Review Practice Test Module A Cells and Cell Processes 1. Which characteristic is shared by all prokaryotes and eukaryotes? a. Ability to store hereditary information b. Use of organelles to control
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Name Date Period Keystone Review Enzymes 1. 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
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CHAPTER 3 3 Solutions of Acids and Bases SECTION Chemical Compounds BEFORE YOU READ After you read this section, you should be able to answer these questions: What are strong and weak acids? What are strong
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Basic Chemistry Why do we study chemistry in a biology course? All living organisms are composed of chemicals. To understand life, we must understand the structure, function, and properties of the chemicals
Chemistry of Life - Part 2 Biological Molecules 1 Of the 92 naturally occurring elements, 16 are known to be important constituents of living systems. The important elements are C, H, O, N, P, S, K, Ca,
The Properties of Water A water molecule is made up of two hydrogen atoms bonded to an oxygen atom. Each end of a water molecule has a slight electric charge. A molecule that has electrically charged areas
AP BIOLOGY SUMMER ASSIGNMENT: 2012-2013 DISTRIBUTED MAY, 2012 Instructor: Mr. Crispin A. Zanca Required Material for Summer Assignment: Contact: email@example.com Course Textbook: Biology 7 th AP Edition
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Name Date _ AP BIOLOGY CHAPTER 2 WORKSHEET MULTIPLE CHOICE. 25 pts. Place the letter of the choice that best completes the statement or answers the question in the blank.. 1. About 25 of the 92 natural
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In the Investigations, you measured several indicators of water quality, including the ph. You may remember that ph values range from 0 to 14. Low values (0 to 6) indicate that a solution is acidic whereas
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