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MemmlersThe Human Body in Health and Disease

11th edition

MemmlersThe Human Body in Health and Disease

11th edition

Chapter 2Chapter 2

Chemistry, Matter, and LifeChemistry, Matter, and Life

Copyright 2009 Wolters Kluwer Health | Lippincott Williams & W ilkins

ChemistryChemistryChemistryChemistry

Science that deals withcomposition andproperties of matter

Used to understandnormal and abnormalfunctioning of body

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Levels of OrganizationLevels of Organization

Chemicals

Cells

Tissues

Organs

ElementsElementsElementsElements

Make up all matter

92 occur in nature, 28created.

Identified by names orchemical symbols(abbreviations of modernor Latin names)

(based on structure ofsubunits or atoms)

Described and organizedin periodic table

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AtomsAtoms

Subunits of elements

Smallest complete units ofmatter

Atomic StructureAtomic Structure

Nucleus

Protons (positive charge [+])

Electrons (negative charge [])

Energy LevelsEnergy Levels

Distances from nucleus where electrons orbit

Higher energy levels can hold more electrons

Electrons in farthest level give atom its characteristicsosi tive or ne ative char e

Valence of element is number of electrons lost or gainedby atoms of element in chemical reactions

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Atomic StructureAtomic Structure

oxygen atom

Molecules and CompoundsMolecules and CompoundsMolecules and CompoundsMolecules and Compounds

Molecules

Formed when two or more atoms unite on the basis

Can be made of like atoms or atoms of differentelements

Compounds

Composed of two or more elements

Smallest subunits of a compound are molecules

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Chemical BondsChemical BondsChemical BondsChemical Bonds

Atoms interact chemicallyto alter neutrality of atomsand form bonds.

http://ibchem.com

Ionic bonding

Electrons transferredbetween atoms form ionicbonds.

ec ro y es on c on sform compounds thatrelease ions when they arein solution

Influence homeostasis(stable condition ofnormal organism)

Conduct electroniccurrent

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Covalent BondsCovalent Bonds

A chemical bond inwhich atoms shareelectrons

Non-polar covalentbond

Polar covalentbond

WaterWater HH22OO

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The Importance of Water

Most abundant

compound in body

Critical in all

in body tissues

Deficiency(dehydration) canthreaten health

Universal solvent

Sta e iqui atordinary

temperatures

Participates inchemical reactions inbody

Mixtures: Solutions and SuspensionsMixtures: Solutions and Suspensions

Solution components

Indistinguishable from one another

Evenly distributed throughout (homogeneous)

Suspension components

Separate from solvent

Settle out (heterogeneous or non-uniform)

Colloid components

Separate from solvent

Evenly distributed throughout

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Compounds: Acids, Bases, and SaltsCompounds: Acids, Bases, and SaltsCompounds: Acids, Bases, and SaltsCompounds: Acids, Bases, and Salts

Compounds are chemical substances with specificproperties

Acid can donate hydrogen ion (H+)

Base (alkali) can accept hydrogen ion (H+)

Salt is formed by a reaction between an acid and a base

The pH ScaleThe pH ScaleThe pH ScaleThe pH Scale

Represents relativeconcentrations ofhydrogen andhydroxide ions in asolution

Scale from 0 (mostacidic) to 14 (mostbasic)

Each unit represents a10-fold change

Body fluids usually7.35-7.45 pH

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BuffersBuffers

Chemicals that prevent sharp changes in hydrogen ionconcentration and maintain relatively constant pH in bodyfluids

Isotopes and RadioactivityIsotopes and RadioactivityIsotopes and RadioactivityIsotopes and Radioactivity

Elements can exist in several forms (isotopes).

Same number of protons and electrons

Different number of neutrons

Different atomic weights

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Use of Radioactive IsotopesUse of Radioactive Isotopes

Radioisotopes are the rays given off by some radioactiveelements.

Can penetrate and destroy cancer cells

Can aid in diagnosis

X-rays

Tracers

Chemistry of Living MatterChemistry of Living MatterChemistry of Living MatterChemistry of Living Matter

Living matter contains 26 of 92 natural elements.

96% of body weightfour elements

4% of body weightnine elements

0.1% of body weight13 elements

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Organic CompoundsOrganic Compounds

Chemical compounds/macromolecules that characterizeliving things

Contain mainly carbon, hydrogen, and oxygen

Carbohydrates

Lipids

Proteins

Nucleic acids

Biological Molecules & Composition of CellsBiological Molecules & Composition of Cells

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CarbohydratesCarbohydrates

Monosaccharides (simple sugars)

Glucose

Disaccharides

Polysaccharides

Starch

Glycogen

LipidsLipids

Triglycerides

Glycerol (glycerin)

Phospholipids

Steroids

Steroid hormones

Sex hormones

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ProteinsProteins

Amino acids

Enzymes

Catalysts

Substrates

ProteinsProteins