Unit 7 HS260 Anatomy, Physiology & Chemistry Amy Habeck, RD, MS, LDN 1

Questions? 2

Objectives Answer your questions Review ▫Chapter 2, Thibodeau & Patton: Structure and Function-Chemistry of Life ▫Chapter 1, Zumdahl: Basic Chemistry-An Introduction 3

Define chemistry 4

Chemistry: the science that deals with the materials of the universe and the changes that these materials undergo 5

What is the difference between physical and chemical changes? Physical changes: Chemical changes: 6

What are some examples of chemical changes? 7

Wood burns in air, forming water, carbon dioxide and other substances A plant grows by assembling simple substances into more complex substances The steel in a car rusts Emissions from a power plant lead to the formation of acid rain. 8

Quantitative vs Qualitative Observations Quantitative observations deal with amounts Qualitative observations deal with things that cannot be measured 9

Scientific Thinking Every-day LifeScientific Problems Recognize the problem Propose possible solutions Decide which solution is best Make an observation Formulate a hypothesis Perform an experiment 10

Scientific Thought What is a theory? What is an observation? What is a law? 11

Scientific Thought What is a theory? ▫A set of tested hypotheses that gives an overall explanation of some part of nature ▫An interpretation or possible explanation of why nature behaves in a particular way What is an observation? ▫Something that is witnessed and can be recorded What is a law? ▫A summary of observed behavior 12

Blood pH – case study Cindy, 5 years old, has been ill for several days with nausea and vomiting. ▫What is the pH of stomach fluid? ▫What is she losing, acid or base? 13

Factors Affecting Blood pH regulation Lungs Kidneys GI tract 14

Questions? 15

Slide 16 LEVELS OF CHEMICAL ORGANIZATION Atoms (Figure 2-1) Fill in the blanks ▫______________ —central core of atom  ______________—positively charged particle in nucleus  ______________—non-charged particle in nucleus  ______________—number of protons in the nucleus; determines the type of atom  ______________—number of protons and neutrons combined ▫______________—regions surrounding atomic nucleus  ______________ —negatively charged particle

Slide 17 LEVELS OF CHEMICAL ORGANIZATION Atoms (Figure 2-1) ▫Nucleus—central core of atom  Proton—positively charged particle in nucleus  Neutron—non-charged particle in nucleus  Atomic number—number of protons in the nucleus; determines the type of atom  Atomic mass—number of protons and neutrons combined ▫Energy levels—regions surrounding atomic nucleus that contain electrons  Electron—negatively charged particle  May contain up to eight electrons in each level  Energy increases with distance from nucleus

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Slide 19 LEVELS OF CHEMICAL ORGANIZATION Elements, molecules, and compounds (Figure 2-2) Fill in the blanks ▫________—a pure substance; made up of only one kind of atom ▫________—a group of atoms bound together in a group ▫________—substances whose molecules have more than one kind of atom

Slide 20 LEVELS OF CHEMICAL ORGANIZATION Elements, molecules, and compounds (Figure 2-2) ▫Element—a pure substance; made up of only one kind of atom ▫Molecule—a group of atoms bound together in a group ▫Compound—substances whose molecules have more than one kind of atom

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Slide 22 CHEMICAL BONDING Chemical bonds form to make atoms more stable ▫Outermost energy level of each atom is full ▫Atoms may share electrons or donate or borrow them to become stable

Slide 23 CHEMICAL BONDING Ionic bonds ▫Ions form when an atom gains or loses electrons in its outer energy level to become stable  _____ ion—has lost electrons; indicated by superscript positive sign(s), as in Na + or Ca ++  ______ion—has gained electrons; indicated by superscript negative sign(s), as in Cl  ▫Ionic bonds form when positive and negative ions attract each other because of electrical attraction ▫________—molecule that dissociates (breaks apart) in water to form individual ions; an ionic compound

Slide 24 CHEMICAL BONDING Ionic bonds ▫Ions form when an atom gains or loses electrons in its outer energy level to become stable  Positive ion—has lost electrons; indicated by superscript positive sign(s), as in Na + or Ca ++  Negative ion—has gained electrons; indicated by superscript negative sign(s), as in Cl  ▫Ionic bonds form when positive and negative ions attract each other because of electrical attraction ▫Electrolyte—molecule that dissociates (breaks apart) in water to form individual ions; an ionic compound

Slide 25 CHEMICAL BONDING ▫_________ bonds form when atoms share their outer energy to fill up and thus become stable ▫_________ bonds do not ordinarily easily dissociate in water

Slide 26 CHEMICAL BONDING Covalent bonds (Figure 2-3) ▫Covalent bonds form when atoms share their outer energy to fill up and thus become stable ▫Covalent bonds do not ordinarily easily dissociate in water

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Slide 28 INORGANIC CHEMISTRY 1._________ molecules contain carbon- carbon covalent bonds or carbon- hydrogen covalent bonds 2._________ molecules do not contain carbon-carbon covalent bonds or carbon- hydrogen covalent bonds Examples of inorganic molecules: water and some acids, bases, and salts

Slide 29 INORGANIC CHEMISTRY Organic molecules contain carbon-carbon covalent bonds or carbon-hydrogen covalent bonds inorganic molecules do not Examples of inorganic molecules: water and some acids, bases, and salts

Slide 30 INORGANIC CHEMISTRY Water ▫Water is a solvent (liquid into which solutes are dissolved), forming aqueous solutions in the body ▫Water is involved in chemical reactions (Figure 2-4) 1.__________—chemical reaction in which water is removed from small molecules so they can be strung together to form a larger molecule 2.__________—chemical reaction in which water is added to the subunits of a large molecule to break it apart into smaller molecules  Chemical reactions always involve energy transfers, as when energy is used to build ATP molecules  Chemical equations show how reactants interact to form products; arrows separate the reactants from the products

Slide 31 INORGANIC CHEMISTRY Water ▫Water is a solvent (liquid into which solutes are dissolved), forming aqueous solutions in the body ▫Water is involved in chemical reactions (Figure 2-4)  Dehydration synthesis—chemical reaction in which water is removed from small molecules so they can be strung together to form a larger molecule  Hydrolysis—chemical reaction in which water is added to the subunits of a large molecule to break it apart into smaller molecules  Chemical reactions always involve energy transfers, as when energy is used to build ATP molecules  Chemical equations show how reactants interact to form products; arrows separate the reactants from the products

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Slide 33 INORGANIC CHEMISTRY Acids, bases, and salts ▫Water molecules dissociate to form equal amounts of H + (hydrogen ion) and OH  (hydroxide ion) 1._______—substance that shifts the H + /OH  balance in favor of H + ; opposite of base 2._______—substance that shifts the H + /OH  balance against H + ; also known as an alkaline; opposite of acid

Slide 34 INORGANIC CHEMISTRY Acids, bases, and salts ▫Water molecules dissociate to form equal amounts of H + (hydrogen ion) and OH  (hydroxide ion) ▫Acid—substance that shifts the H + /OH  balance in favor of H + ; opposite of base ▫Base—substance that shifts the H + /OH  balance against H + ; also known as an alkaline; opposite of acid

Slide 35 INORGANIC CHEMISTRY Acids, bases, and salts (cont.) ▫pH—mathematical expression of relative H + concentration in an aqueous solution (Figure 2-5)  pH 7 is neutral (neither acid nor base)  pH values above 7 are basic; pH values below 7 are acidic 1.____________ occurs when acids and bases mix and form salts 2.____________ are chemical systems that absorb excess acids or bases and thus maintain a relatively stable pH

Slide 36 INORGANIC CHEMISTRY Acids, bases, and salts (cont.) ▫pH—mathematical expression of relative H + concentration in an aqueous solution (Figure 2-5)  pH 7 is neutral (neither acid nor base)  pH values above 7 are basic; pH values below 7 are acidic ▫Neutralization occurs when acids and bases mix and form salts ▫Buffers are chemical systems that absorb excess acids or bases and thus maintain a relatively stable pH

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Slide 38 ORGANIC CHEMISTRY Carbohydrates—sugars and complex carbohydrates (Figure 2-6) ▫Contain carbon (C), hydrogen (H), oxygen (O) ▫Made up of six-carbon subunits called ____________ or single sugars (e.g., glucose) ▫Disaccharide—double sugar made up of two monosaccharide units (e.g., sucrose, lactose) ▫Polysaccharide—complex carbohydrate made up of many monosaccharide units (e.g., glycogen made up of many glucose units) ▫Function of carbohydrates is to store energy for later use

Slide 39 ORGANIC CHEMISTRY Carbohydrates—sugars and complex carbohydrates (Figure 2-6) ▫Contain carbon (C), hydrogen (H), oxygen (O) ▫Made up of six-carbon subunits called monosaccharides or single sugars (e.g., glucose) ▫Disaccharide—double sugar made up of two monosaccharide units (e.g., sucrose, lactose) ▫Polysaccharide—complex carbohydrate made up of many monosaccharide units (e.g., glycogen made up of many glucose units) ▫Function of carbohydrates is to store energy for later use

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Slide 41 ORGANIC CHEMISTRY Lipids—fats and oils ▫Triglycerides (Figure 2-7)  Made up of one glycerol unit and three fatty acids  Store energy for later use ▫Phospholipids (Figure 2-8)  Similar to triglyceride structure, except with only two fatty acids, and with a phosphorus-containing group attached to glycerol  The head attracts water and the double tail does not, thus forming stable double layers (bilayers) in water  Form membranes of cells ▫Cholesterol  Molecules have a steroid structure made up of multiple rings  Cholesterol stabilizes the phospholipid tails in cellular membranes and is also converted into steroid hormones by the body

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Slide 45 ORGANIC CHEMISTRY Proteins (Figure 2-9) ▫Very large molecules made up of amino acids held together in long, folded chains by peptide bonds ▫Structural proteins  Form structures of the body  Collagen is a fibrous protein that holds many tissues together  Keratin forms tough, waterproof fibers in the outer layer of the skin

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Slide 47 ORGANIC CHEMISTRY Proteins (cont.) ▫Functional proteins  Participate in chemical processes  Examples: hormones, cell membrane channels and receptors, enzymes  Enzymes (Figure 2-10)  Catalysts—help chemical reactions occur  Lock-and-key model—each enzyme fits a particular molecule that it acts on as a key fits into a lock ▫Proteins can combine with other organic molecules to form glycoproteins or lipoproteins

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Slide 49 ORGANIC CHEMISTRY Nucleic acids ▫Made up of nucleotide units ▫Sugar (ribose or deoxyribose) ▫Phosphate  Nitrogen base (adenine, thymine or uracil, guanine, cytosine)

Slide 50 ORGANIC CHEMISTRY Nucleic acids (cont.) ▫DNA (deoxyribonucleic acid) (Figure 2-11)  Used as the cell’s “master code” for assembling proteins  Uses deoxyribose as the sugar and A, T (not U), C, and G as bases  Forms a double helix shape ▫RNA (ribonucleic acid)  Used as a temporary “working copy” of a gene (portion of the DNA code)  Uses ribose as the sugar and A, U (not T), C, and G as bases ▫By directing the formation of structural and functional proteins, nucleic acids ultimately direct overall body structure and function

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Questions? 52

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