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Transcript of Matter is anything that has mass and takes up space. Energy is anything that brings about change....
• Matter is anything that has mass and takes up space.
• Energy is anything that brings about change.
• Everything in your environment, including you, is made of matter.
The Nature of Matter
Chemistry of LifeChemistry of Life
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• Energy can hold matter together or break it apart.
• At the center of an atom is a nucleus that contains protons and neutrons.
• Outside the nucleus are electrons, each of which has a negative charge.
Atoms
Chemistry in LifeChemistry in Life
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Click image to view movie.
• Although they have nearly equal masses, a proton has a positivecharge and a neutron has no charge.
• Electrons are the part of the atom that is involved in chemical reactions.
• An atom is mostly empty space. Energy holds the parts of an atom together.
Atoms
Chemistry in LifeChemistry in Life
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• When something is made up of only one kind of atom, it is called an element.
• An element can’t be broken down into a simpler form by chemical reactions.
Elements
Chemistry in LifeChemistry in Life
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• Scientists have given each element its own one- or two-letter symbol.
• All elements are arranged in a chart known as the periodic table of elements.
• The table provides information about each element including its mass, how many protons it has, and its symbol.
Elements
Chemistry in LifeChemistry in Life
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Elements
Chemistry in LifeChemistry in Life
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• Compounds are made up of two or more elements in exact proportions.
• For example, pure water is always made up of hydrogen atoms bonded to oxygen atoms in a ratio of two hydrogen atoms to one oxygen atom.
Compounds and Molecules
Chemistry in LifeChemistry in Life
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• There are two types of compounds— molecular compounds and ionic compounds.
• The smallest part of a molecular compound is a molecule.
• A molecule is a group of atoms held together by the energy of chemical bonds.
Molecular Compounds
Chemistry in LifeChemistry in Life
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Molecular Compounds
Chemistry in LifeChemistry in Life
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• When chemical reactions occur, chemical bonds break, atoms are rearranged, and new bonds form.
• The molecules produced are different from those that began the chemical reaction.
Molecular Compounds
Chemistry in LifeChemistry in Life
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• Water does not have the same properties as oxygen and hydrogen.
• Molecular compounds form when different atoms share their outermost electrons. Twoatoms of hydrogen each can share one electron on one atom of oxygen to form one molecule of water.
• Atoms also combine because they’ve become positively or negatively charged.
Ions
Chemistry in LifeChemistry in Life
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• Atoms are usually neutral—they have no overall electric charge.
• When an atom loses an electron, it has more protons than electrons, so it becomes positively charged.
• When an atom gains an electron, it has more electrons than protons, so it becomes negatively charged.
Ions
Chemistry in LifeChemistry in Life
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• Electrically charged atoms—positive or negative—are called ions.
• Ions of opposite charges attract one another to form electrically neutral compounds called ionic compounds.
Ionic Compounds
Chemistry in LifeChemistry in Life
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• Table salt is made of sodium (Na) and chlorine (Cl) ions.
• When they combine, a chlorine atom gains an electron from a sodium atom.
• The chlorine atom becomes a negatively charged ion, and the sodium atom becomes a positively charged ion.
• These oppositely charged ions then are attracted to each other and form the ionic compound sodium chloride, NaCl.
Ionic Compounds
Chemistry in LifeChemistry in Life
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Ionic Compounds
Chemistry in LifeChemistry in Life
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• Messages are sent along your nerves as potassium and sodium ions move in and out of nerve cells.
• Calcium ions are important in causing your muscles to contract.
• A mixture is a combination of substances in which individual substances retain their own properties.
Mixtures
Chemistry in LifeChemistry in Life
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Mixtures
Chemistry in LifeChemistry in Life
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• Mixtures can be solids, liquids, gases, or any combination of them.
• Most chemical reactions in living organisms take place in mixtures called solutions.
• In a solution, two or more substances are mixed evenly.
Mixtures
Chemistry in LifeChemistry in Life
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• A suspension is formed when a liquid or a gas has another substance evenly spread throughout it.
• Unlike solutions, the substances in a suspension eventually sink to the bottom.
• All living things are made up of compounds that are classified as organic or inorganic.
Organic Compounds
Chemistry in LifeChemistry in Life
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• Rocks and other nonliving things contain inorganic compounds.
• Organic Compounds always contain carbon and hydrogen and usually are associated with living things.
• Organic molecules can contain hundreds or even thousands of atoms that can be arranged in many ways.
Organic Compounds
Chemistry in LifeChemistry in Life
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Organic Compounds
Chemistry in LifeChemistry in Life
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• Four groups of organic compounds make up all living things—carbohydrates, lipids, proteins, and nucleic acids.
• Carbohydrates are organic molecules that supply energy for cell processes.
Carbohydrates
Chemistry in LifeChemistry in Life
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• Sugars and starches are carbohydrates that cells use for energy.
• Some carbohydrates also are important parts of cell structures.
• Lipids do not mix with water.
Lipids
Chemistry in LifeChemistry in Life
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• Lipids such as fats and oils store and release even larger amounts of energy than carbohydrates do.
• One type of lipid, the phospholipid, is a major part of cell membranes.
• Certain proteins called enzymes regulate nearly all chemical reactions in cells.
• Proteins are made up of smaller molecules called amino acids.
Proteins
Chemistry in LifeChemistry in Life
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• Proteins are the building blocks of many structures in organisms.
• Your muscles contain large amounts of protein.
• Proteins are scattered throughout cell membranes.
• Another nucleic acid, ribonucleic acid, or RNA, is needed to make enzymes and other proteins.
• Large organic molecules that store important coded information in cells are called nucleic acids.
Nucleic Acids
Chemistry in LifeChemistry in Life
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• One nucleic acid, deoxyribonucleic acid, or DNA—genetic material—is found in all cells at some point in their life.
• Inorganic compounds are the source for many elements needed by living things.
• Most inorganic compounds are made from elements other than carbon.
Inorganic Compounds
Chemistry in LifeChemistry in Life
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• Generally inorganic molecules contain fewer atoms than organic molecules.
• Inorganic compounds can contain the elements nitrogen, phosphorus, and sulfur.
Inorganic Compounds
Chemistry in LifeChemistry in Life
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• One of the most important inorganic compounds for living things is water.
• Living things are composed of more than 50 percent water and depend on water to survive.
Importance of Water
Chemistry in LifeChemistry in Life
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• You can live for weeks without food but only a few days without water.
Importance of Water
Chemistry in LifeChemistry in Life
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• Although seeds and spores of plants, fungi, and bacteria can exist without water, they must have water if they are to grow and reproduce.
• All the chemical reactions in living things take place in water solutions, and most organisms use water to transport materials through their bodies.
Importance of Water
Chemistry in LifeChemistry in Life
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• Plants use water to move minerals and sugars between roots and leaves.
• The atoms of a water molecule are arranged in such a way that the molecule has areas with different charges.
Characteristics of Water
Chemistry in LifeChemistry in Life
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• Water molecules are like magnets.
• The negative part of a water molecule is attracted to the positive part of another water molecule just like the north pole of a magnet is attracted to the south pole of another magnet.
• This attraction, or force, between water molecules is why a film forms on the surface of water.
Characteristics of Water
Chemistry in LifeChemistry in Life
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• The film is strong enough to support small insects because the forces between the water molecules are stronger than the force of gravity on the insect.
• Because water molecules are so strongly attracted to each other, the temperature of water changes slowly.
Characteristics of Water
Chemistry in LifeChemistry in Life
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• The large percentage of water in living things acts like an insulator.
• The water in a cell helps keep its temperature constant, which allows life-sustaining chemical reactions to take place.
• When water freezes, ice crystals form.
Characteristics of Water
Chemistry in LifeChemistry in Life
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• In the crystals, each water molecule is spaced at a certain distance from all the others.
• Because this distance is greater in frozen water than in liquid water, ice floats on water.
• Bodies of water freeze from the top down.
• The floating ice provides insulation and allows living things to survive.
Question 1
Answer
_______ is anything that has mass and takes up space.
The answer is Matter. Everything in your environment is made of matter.
Section CheckSection Check
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Question 2
Answer
A(n) _______ is made up of only one kind of atom.
The answer is element. An element can’t be broken down into a simpler form by chemical reactions.
Section CheckSection Check
11
11Section CheckSection Check
Question 3Which best describes the structure in this illustration?
A. atomB. elementC. molecular compoundD. ionic compound
11Section CheckSection Check
Answer
The answer is C. Molecular compounds form when different atoms share their outermost electrons.
Trapping and Using Energy
• All of the activities of an organism involve chemical reactions in some way.
• The total of all chemical reactions in an organism is called metabolism.
Energy for LifeEnergy for Life
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• The chemical reactions of metabolism need enzymes.
Trapping and Using Energy• Enzymes in cells cause a change, but the
enzyme is not changed and can be used again.• Enzymes also can cause molecules to join.
Energy for LifeEnergy for Life
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• Without the right enzyme, a chemical reaction in a cell cannot take place.
• Each chemical reaction in a cell requires a specific enzyme. Click image to view movie.
Photosynthesis
• Living things are divided into two groups— producers and consumers—based on how they obtain their food.
• Organisms that make their own food, such as plants, are called producers.
Energy for LifeEnergy for Life
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• Organisms that cannot make their own food are called consumers.
Photosynthesis
• Plants and many other producers can convert light energy into another kind of energy—chemical energy.
• The process they use is called photosynthesis.
Energy for LifeEnergy for Life
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• During photosynthesis, producers use light energy to make sugars, which can be used as food.
Producing Carbohydrates
• Producers that use photosynthesis are usually green because they contain a green pigment called chlorophyll (KLOR uh fihl).
• Chlorophyll and other pigments are used in photosynthesis to capture to capture light energy.
Energy for LifeEnergy for Life
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• In plant cells, these pigments are found in chloroplasts.
Producing Carbohydrates
• The captured light energy is used to drive chemical reactions during which the raw materials, carbon dioxide and water, are used to produce sugar and oxygen.
• For plants, the raw materials come from air and soil.
Energy for LifeEnergy for Life
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Producing Carbohydrates
• Some of the captured light energy is stored in the chemical bonds that hold sugar molecules together.
Energy for LifeEnergy for Life
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Storing Carbohydrates
• Plants make more sugar during photosynthesis than they need for survival.
Energy for LifeEnergy for Life
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• Excess sugar is changed and stored as starches or used to make other carbohydrates.
• Plants use carbohydrates as food for growth, maintenance, and reproduction.
• Consumers take in food by eating producers or other consumers.
Respiration
• Some of the energy from the food you eat is used to make you move.
Energy for LifeEnergy for Life
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• Some of it becomes thermal energy, which is why you feel warm or hot when you exercise.
• Most cells also need oxygen to break down food.
Respiration
• During respiration, chemical reactions occur that break down food molecules into simpler substances and release their stored energy.
Energy for LifeEnergy for Life
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• Just as in photosynthesis, enzymes are needed for the chemical reactions of respiration.
Breaking Down Carbohydrates• The type of food molecules most easily
broken down by cells is carbohydrates.
Energy for LifeEnergy for Life
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• Respiration of carbohydrates begins in the cytoplasm of the cell.
• The carbohydrates are broken down into glucose molecules.
• Each glucose molecule is broken down further into two simpler molecules.
• As the glucose molecules are broken down, energy is released.
Breaking Down Carbohydrates
• The two simpler molecules are broken down again. This breakdown occurs in the mitochondria of the cells of plants, animals, fungi, and many other organisms.
Energy for LifeEnergy for Life
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• This process uses oxygen, releases much more energy, and produces carbon dioxide and water as wastes.
Breaking Down Carbohydrates
• When you exhale you breathe out carbon dioxide and some of the water.
Energy for LifeEnergy for Life
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• Respiration occurs in the cells of all living things.
Fermentation
• When cells do not have enough oxygen for respiration, they use a process called fermentation to release some of the energy stored in glucose molecules.
Energy for LifeEnergy for Life
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• Like respiration, fermentation begins in the cytoplasm.
Fermentation
• Again, as the glucose molecules are broken down, energy is released.
Energy for LifeEnergy for Life
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• But the simple molecules from the breakdown of glucose do not move into the mitochondria.
• Instead, more chemical reactions occur in the cytoplasm.
Fermentation
• These reactions release some energy and produce wastes.
Energy for LifeEnergy for Life
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• Depending on the type of cell, the wastes may be lactic acid, alcohol, and carbon dioxide.
• The presence of lactic acid is why your muscle cells might feel stiff and sore after you exercise.
Related Processes
• During photosynthesis and respiration, what is produced in one is used in the other.
Energy for LifeEnergy for Life
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• Photosynthesis produces sugars and oxygen, and respiration uses these products,
• The carbon dioxide and water produces during respiration are used during photosynthesis
Question 1
Answer
_______ is the total of all chemical reactions in an organism.
The answer is metabolism. All of the activities of an organism involve chemical reactions in some way.
Section CheckSection Check
33
33Section CheckSection Check
Question 2
Which does this equation represent?
A. respirationB. fermentation
C. photosynthesisD. chemosynthesis
33Section CheckSection Check
Answer
The answer is C. During photosynthesis, plants take in carbon dioxide and water and combine it with light energy to make sugars, which they use for food.
Question 3
Answer
_______ is the type of food molecules most easily broken down by cells.
The answer is carbohydrates. As carbohydrates are broken down, energy is released.
Section CheckSection Check
33
Chapter 9 Review 1 of 2
• Animals, plants, fungi, and many other organisms undergo respiration.
• Plants use chlorophyll to produce glucose.
• Photosynthesis results in the release of oxygen.
• In respiration, glucose is broken down.
• Consumers: organisms that can’t make their own food.
Chapter 9 Review 2 of 2
• Enzymes: proteins that speed up chemical reactions.
• Photosynthesis: changing light energy into chemical energy.
• Producers: organisms that make their own food.• The energy used in photosynthesis comes from
the Sun.• All living things are made up of organic
compounds.