Simple Things of Life

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Simple Things of Life

• Bio 100
• Tri-County Technical College
• Pendleton, S. C.

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Matter does matter

• Matter
• anything that has mass and occupies space
• composed of one or more elements
• Elements
• oxygen, carbon, aluminum, etc
• Periodic Table of the Elements
• Matter exists in states.

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States of matter

• Solid, liquid, gas
• Solid
• molecules closely packed together
• molecules exhibit the least kinetic energy
• Liquid
• molecules further apart than in a solid
• molecules flow past each other
• molecules exhibit greater kinetic energy

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States of matter, ctd.

• Gases
• molecules furthest apart
• molecules have the most kinetic energy
• molecules flow past each other
• Water can exist in all three forms of matter
• solid -- ice
• liquid -- water
• gas -- steam

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Heat and Temperature

• HEAT is the amount of energy associated with
  movement of atoms/molecules in body of matter
• TEMPERATURE measures intensity of heat the
  average speed of the molecules rather than the
  total amount of energy in a body of matter

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The Atom

• The basic unit of matter
• Areas of an atom
• nucleus
• electron shells
• The atomic nucleus
• contains positive, negative and neutral particles

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Atomic nuclear particles

• Protons
• positively charged particles
• Neutrons
• particles in the nucleus with no charge
• not either positive or negative
• The number of protons equals the atomic number of
  an atom.
• periodic table

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Atomic number and mass number

• Mass Number (atomic mass)
• equals the number of protons number of neutrons
  in the nucleus of an atom
• How can you determine the number of neutrons?
• subtract the atomic number from the atomic mass
  number
• neutronsatomic mass number - atomic

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Isotopes

• have different numbers of neutrons
• different forms of the same atom
• For example
• carbon
• carbon-12 and carbon-14
• both are carbon but they have different numbers
  of neutrons in their nuclei
• some isotopes are radioactive

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Radioactive isotopes

• the nucleus is not stable
• nucleus disintegrates and releases particles and
  energy
• disintegrations can be detected using a Geiger
  counter
• medical uses of radioisotopes

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Medical uses of radioisotopes

• thyroid function testing
• thyroid absorbs and concentrates iodine
• give the patient radioactive iodine
• place a Geiger counter-like device over the
  thyroid area
• normal counts indicate normal thyroid function
• greater than normal counts -- hyperthyroidism
• less than normal counts -- hypothyroidism

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Atomic Symbols

• shorthand symbols for atoms
• C-carbon H- hydrogen O- oxygen
• P-phosphorus
• K-potassium
• Mg-magnesium
• N-nitrogen
• O oxygen
• C, N, O, P comprise 96 of living matter

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Trace Elements

• Trace elements are needed by body in minute
  quantities ONLY
• Example is iodine (I) is essential ingredient of
  hormone produced by thyroid
• Only 0.15 mg iodine needed daily
• Deficiency causes goiter
• Same price, why not?

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Chemical Equations

• Tell us what is happening in very general terms
• ?read as goes to or becomes
• 6CO2 6H2O ? C6H12O6 6O2
• Arrows in both directions means the reaction is
  reversible (can proceed in both direction)
• Water disassociation into H and OH-

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Chemical Bonding

• Two or more atoms often form links between each
  other involving electrons.
• Chemical Bonds
• Kinds of chemical bonds
• Ionic
• Covalent
• Hydrogen bonds will also be discussed.

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Covalent Bonding

• Two atoms share electrons and neither atom
  becomes an ion
• Polar and nonpolar covalent bonds
• Some atoms hold the electrons a little closer
  than the other one and become slightly negative
• the other atom becomes slightly positive

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Covalent Bond Examples

• Carbon and hydrogen
• produce methane -- CH4
• Hydrogen and oxygen
• produce water -- H2O
• Oxygen becomes slightly positive
• Hydrogen becomes slightly negative
• Covalent compounds have covalent bonds.

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Hydrogen Bonds

• form between molecules in which hydrogen is
  bonded to a large electron-hungry atom
• H2O is an example
• the oxygen end is slightly negative
• the hydrogen end is slightly positive
• Hydrogen bonds hold together --
• proteins
• nucleic acids -- DNA and RNA

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Water and Polar Molecules

• Four electronegative atoms of interest
• O, N, P, and S
• See those in formula, think polar and uneven
  distribution of charge
• Should also think hydrogen bonding
• Water is polar molecule
• Important because of cohesive nature, ability to
  moderate temperature, biological significance of
  ice floating, and versatility as solvent

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Which is what, and why?

• SOLUTION is the result of mixing solute(s) with
  solvent(s)
• SOLUTE is what is being dissolved
• SOLVENT is what is doing the dissolving
• Solute solvent solution
• Major biological solvent is WATER
• AQUEOUS solution is mixture of solute(s) with
  water acting as the solvent
• HYPER HYPO and ISO are terms used to describe
  SOLUTE CONCENTRATION(S)

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Please pass the salt.

• Compounds formed by ionic bonds called ionic
  compounds or SALTS
• Examples NaCl, CaCl2, MgCl2
• Dissolved in water to yield electrolytes (charged
  particles)
• Electrolytes very important to living systems

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Ionic Bonds

• One atoms steals one or more electrons from
  another atom.
• The atom that loses the electron
• becomes positively charged -- cation
• The atom that gains the electron
• becomes negative charged -- anion
• Opposites attract

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Ionic Bonds--Examples

• Sodium and Chlorine
• Sodium loses an electron and becomes positive
• Chlorine gains an electron and become negative
• The positive sodium ion is attracted to the
  negative chloride ion.
• NaCl-
• Acids, bases, and salts have ionic bonds.

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Acids, bases, and salts

• Salts
• cation is something other than the hydrogen ion
• NaCl, KCl, Na2HPO4
• referred to as electrolytes in the human body
• they conduct an electric current
• they have a salty taste
• they are lost in sweat and other body fluids

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Acids, bases, and salts, ctd.

• Acids
• cation is the hydrogen ion
• when added to water the acidity increases
• have a sour taste
• they donate hydrogen ions in a solution
• HCl -- stomach acid
• H2SO4 -- sulfuric acid

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Acids, bases, and salts, ctd.

• Bases
• cation is something other than the hydrogen ion
• anion is often the hydroxyl ion -- -OH
• when added to a solution the acidity decreases
• have a bitter taste
• they take hydrogen ions out of solution
• NaOH -- sodium hydroxide
• KOH -- potassium hydroxide

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Levels of acidity

• The level of acidity in the living is very
  important because enzymes dont work well if the
  level of acidity is too low or too high.
• The level of acidity is related to the
  concentration of hydrogen ions in a solution.
• very small concentration in living systems
• 1.0 x 10-7

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Expressing acidity

• 1.0 x 10-7 and 0.0000001 are cumbersome to
  manipulate and compare.
• To deal with this someone developed the concept
  of pH
• pH equals the negative logarithm of the hydrogen
  ion concentration

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Calculation of pH

• hydrogen ion conc.
• 1.0 x 10-1
• 1.0 x 10-2
• 1.0 x 10-3
• 1.0 x 10-4
• 1.0 x 10-5
• 1.0 x 10-6
• 1.0 x 10-7

• What is the pH?
• pH 1.0
• pH 2.0
• pH 3.0
• pH 4.0
• pH 5.0
• pH 6.0
• pH 7.0

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Calculation of pH

• hydrogen ion conc.
• 1.0 x 10-8
• 1.0 x 10-9
• 1.0 x 10-10
• 1.0 x 10-11
• 1.0 x 10-12
• 1.0 x 10-13
• 1.0 x 10-14

• What is the pH?
• pH 8.0
• pH 9.0
• pH 10.0
• pH 11.0
• pH 12.0
• pH 13.0
• pH 14.0

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pH calculation, ctd.

• Note
• as the pH number increases, the hydrogen ion
  concentration decreases.
• as the pH number decreases the hydrogen ion
  concentration increases
• each change in pH values represents a 10x change
  in hydrogen ion concentration

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What does all this mean?

• pH ranges in values from 0-14.
• A pH of 7.0 is neutral.
• Any pH less than 7.0 is acidic.
• Any pH greater than 7.0 is basic or alkaline.
• Most living systems operate at a pH of around 7.0
• human body pH range 7.35-7.45

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What is that falling from the sky

• Acid precipitation refers to rain, snow, or fog
  more acidic than pH 5.6
• Sulfur and nitrogen oxide gases that react with
  water in air to form strong acids
• Northeastern US and Canada
• Lakes and streams forests and grasslands, and
  topsoil adversely affected
• pH very important factor in determining what can
  live and where
• Hope?

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Buffers and then some

• Buffer is substance consisting of acid and base
  forms in solution that minimizes changes in pH
  when extraneous acids or bases are added to
  solution
• Carbonic acid (H2CO3) dissociates to yield
  bicarbonate ion (HCO3-) and a hydrogen ion (H)
• Buffer works by accepting hydrogen ions from the
  solution when they are in excess and donating
  hydrogen ions to the solution when they have been
  depleted

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The part of the end before the next beginning.