Chapter 2: Basic Chemistry of Physiology

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Matter

The "stuff" of the universe, Anything that has mass and takes up space

States of matter: Solid

has definite shape and volume

States of matter: Liquid

has definite volume, changeable shape

States of matter: Gas

has changeable shape and volume

Energy

The capacity to do work (put matter into motion)

Types of energy: Kinetic

energy in action

Types of energy: Potential

energy of position; stored (inactive) energy

Forms of Energy: Chemical

stored in the bonds of chemical substances

Forms of Energy: Electrical

results from the movement of charged particles

Forms of Energy: Mechanical

directly involved in moving matter

Forms of Energy: Radiant or electromagnetic

energy traveling in waves (i.e., visible light, ultraviolet light, and X rays)

Composition of Matter: Elements

unique substances that cannot be broken down by ordinary chemical means

Composition of Matter: Atoms

more-or-less identical building blocks for each element

Composition of Matter: Atomic symbol

one- or two-letter chemical shorthand for each element

Major Elements of the Human Body

Oxygen (O) Carbon (C) Hydrogen (H) Nitrogen (N)

Lesser and Trace Elements of the Human Body

Lesser elements make up 3.9% of the body and include: Calcium (Ca), phosphorus (P), potassium (K), sulfur (S), sodium (Na), chlorine (Cl), magnesium (Mg), iodine (I), and iron (Fe) - Trace elements make up less than 0.01% of the body, They are required in minute amounts, and are found as part of enzymes

Atomic Structure: nucleus

The nucleus consists of neutrons and protons

Atomic Structure: Neutrons

have no charge and a mass of one atomic mass unit (amu)

Atomic Structure: Protons

have a positive charge and a mass of 1 amu

Atomic Structure: Electrons

Electrons are found orbiting the nucleus, They have a negative charge and 1/2000 the mass of a proton (0 amu)

Models of the Atom: Planetary Model

electrons move around the nucleus in fixed, circular orbits

Models of the Atom: Orbital Model

regions around the nucleus in which electrons are most likely to be found

Atomic number

equal to the number of protons

Mass number

equal to the mass of the protons and neutrons

Atomic weight

average of the mass numbers of all isotopes

Isotope

atoms with same number of protons but a different number of neutrons

Radioisotopes

atoms that undergo spontaneous decay called radioactivity

Molecule

two or more atoms held together by chemical bonds

Compound

two or more different kinds of atoms chemically bonded together

Mixtures

two or more components physically intermixed (not chemically bonded)

Solutions

homogeneous mixtures of components

Solvent

substance present in greatest amount

Solute

substance(s) present in smaller amounts

Colloids, or Emulsions

heterogeneous mixtures whose solutes do not settle out

Suspensions

heterogeneous mixtures with visible solutes that tend to settle out

Mixtures Compared with Compounds: Mixtures

No chemical bonding takes place in mixtures, Most mixtures can be separated by physical means, Mixtures can be heterogeneous or homogeneous

Mixtures Compared with Compounds: Compounds

Compounds cannot be separated by physical means, All compounds are homogeneous

Chemical Bonds

Electron shells, or energy levels, surround the nucleus of an atom, Bonds are formed using the electrons in the outermost energy level

Valence shell

outermost energy level containing chemically active electrons

Octet rule

atoms react in a manner to have 8 electrons in their valence shell

Inert elements

have their outermost energy level fully occupied by electrons

Reactive elements

do not have their outermost energy level fully occupied by electrons

Types of Chemical Bonds

Ionic, Covalent, Hydrogen

Ionic Bonds

Ions are charged atoms resulting from the gain or loss of electrons, Anions have gained one or more electrons, Cations have lost one or more electrons, Opposite charges on anions and cations hold them close together, forming ionic bonds

Formation of an Ionic bond

Ionic compounds form crystals instead of individual molecules, Example: NaCl (sodium chloride)

Covalent Bonds

Electrons are shared by two atoms, Electron sharing produces molecules

Hydrogen Bonds

Too weak to bind atoms together, Common in dipoles such as water, Responsible for surface tension in water, Important as intramolecular bonds, giving the molecule a three-dimensional shape

Chemical Reactions

Occur when chemical bonds are formed, rearranged, or broken

Patterns of Chemical Reactions: Combination reactions:

Synthesis reactions which always involve bond formation, A + B r AB

Patterns of Chemical Reactions: Decomposition reactions

Molecules are broken down into smaller molecules, AB r A + B

Patterns of Chemical Reactions: Exchange reactions

Bonds are both made and broken, AB + C 6 AC + B

Patterns of Chemical Reactions: Oxidation-Reduction (Redox) Reactions

Reactants losing electrons are electron donors and are oxidized, Reactants taking up electrons are electron acceptors and become reduced

Exergonic reactions

reactions that release energy

Endergonic reactions

reactions whose products contain more potential energy than did its reactants

Rate of Chemical Reactions: Temperature

chemical reactions proceed quicker at higher temperatures

Rate of Chemical Reactions: Particle size

the smaller the particle the faster the chemical reaction

Rate of Chemical Reactions: Concentration

higher reacting particle concentrations produce faster reactions

Rate of Chemical Reactions: Catalysts

increase the rate of a reaction without being chemically changed

Rate of Chemical Reactions: Enzymes

biological catalysts

Water: High heat capacity

absorbs and releases large amounts of heat before changing temperature

Water: High heat of vaporization

changing from a liquid to a gas requires large amounts of heat

Water: Polar solving properties

dissolves ionic substances, forms hydration layers around large charged molecules, and serves as the body's major transport medium

Water: Reactivity

is an important part of hydrolysis and dehydration synthesis reactions

Water: Cushioning

resilient cushion around certain body organs

Acidic Solutions:

Higher H+ concentration and therefore a lower pH - pH 0-6.99

Alkaline Solutions

Lower H+ concentration and therefore a higher pH - pH 7.01-14

Neutral Solutions

Equal H+ and OH- concentrations - pH 7.00

Buffers:

Systems that resist abrupt and large swings in the pH of body fluids

Buffers: Carbonic acid

bicarbonate system- Carbonic acid dissociates reversibly releasing bicarbonate ions and protons, The chemical equilibrium between carbonic acid and bicarbonate resists pH changes in the blood

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