CHAPTER TWO ESSENTIAL CHEMISTRY FOR BIOLOGY

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					CHAPTER TWO: ESSENTIAL CHEMISTRY FOR BIOLOGY

Only two things exist in the universe: matter and energy. All living and nonliving things consist of a
combination of matter and energy. Some substances have a little matter and a lot of energy and other
substances have a lot of matter and a little energy.

•     ENERGY

    DEFINITION         Force that changes matter.

    TWO STATES         POTENTIAL

                       KINETIC

    MANY FORMS         Including electrical, nuclear, chemical, heat and light.



•     MATTER

    DEFINITION     Anything that occupies space and has mass. All forms of matter are composed of
                   atoms, including living things.
    FOUR STATES

      SOLID

      LIQUID

      GAS

      PLASMA

    UNIT OF STRUCTURE KNOWN AS THE ATOM.



•     STRUCTURE AND ORGANIZATION OF ATOMS

    NUCLEUS

      PROTONS

      NEUTRONS

    ELECTRON CLOUD

      ELECTRONS



Atomic mass means the total mass of an atom but includes only the mass of the protons and neutrons.




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Atomic number refers to the number of protons in an atom’s nucleus. An element is a group of atoms
that are all the same type (having the same atomic number).

•     THE PERIODIC TABLE

This table is a classification system for all known forms of atoms (elements) including 92 naturally
occurring elements and a number (ever increasing) of synthetically produced elements.

•     ISOTOPES

Some atoms have large, unstable nuclei and over time they lose or gain the energy-equivalents of a
neutron.

Their mass then varies from the standard form of the element that is listed on the Periodic Table,
but their proton number remains the same.

If their mass is different from the standard form of that particular element which is listed on the
Periodic Table, then we call the form of the atom with the mass variation an isotope of the standard
form.

    HALF LIFE

    RADIOMETRIC DATING

    RADIOACTIVE TAGS

    RADIOACTIVE TRACERS



•     HOW ATOMS BOND TOGETHER TO CREATE MOLECULES

    COVALENT BONDS       Called a sharing bond.

    POLAR COVALENT       A bond that is not totally neutral, rather it has areas of partial charge.
                         Water is an example.
    IONIC BONDS          Atoms lose their neutrality and gain a charge by losing or gaining electrons.
                         They become ions in the process.
                         POSITIVE ION

                         NEGATIVE ION



Because water is a polar covalent molecule it can form energy associations with many different types
of atoms or molecules.

That is why we call it a good solvent.

    POLAR STRUCTURE

    COHESIVE PROPERTIES




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    ADHESIVE PROPERTIES

    ABSORBS HEAT



•     pH

    DEFINITION OF pH   Measure of the amount of free H+ (or lack thereof) in a solution.

    pH SCALE           1-6.9 indicates an acid, 7 means that the solution is neutral and 7.1-14
                       indicates that the solution is alkaline (base or basic).
    NEUTRAL            Balanced. The +ions and –ions are equal.

    ACID               Releases an excess of H+ ions into solution.

    ALKALINE (BASE)    Releases an excess of OH- ions into solution.

    BUFFER             A chemical (usually a protein) that can resist a change in the environmental
                       pH. Helps maintain homeostasis.




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