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Chapter 2
Concepts of Matter and Energy
MatterFound
Can
in either solid, liquid, or gas states.
be changed physically or chemically
EnergyKinetic
Energy-
Potential
All
Energy-
forms of energy exhibit both kinetic and potential work capacities
Forms
of energy:
-Chemical-Electrical-Mechanical-RadiantEnergy
can easily be converted from one form to another (with a few
exceptions).
-Energy conversion is not very efficient, lose a lot to heat
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Composition of Matter
ElementA
list of the known elements are organized in the periodic table
AtomAtomic symbolAtomic Structure
Protons-
Neutrons-
Electrons-
Planetary
and Orbital Models of the atom- See figure 2.1
Identifying atoms- varying number of protons, neutrons, and electrons makes
each atom different.
Atomic
Number-
Atomic
Mass-
Atomic
Weight-
-Isotope- varying forms of an individual atom, the isotope of each
atom has the same number of protons and electrons, but varies in
number of neutrons.
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Molecules and Compounds
MoleculeCompoundChemical Bonds and Chemical Reactions
Chemical ReactionBond Formation- When atoms unite chemically, chemical bonds are formed.
Role
of electrons in bonding- outer most electrons are involved in
bonding.
What
makes a chemical bond?
1)
2)
Three types of chemical bonds
Ionic
bonds-
Covalent
bonds-
Hydrogen
bonds-
Patterns of Chemical Reactions
Synthesis
reaction-
Decomposition
Exchange
reaction-
reaction3
Biochemistry: The chemical composition of living matter
Inorganic CompoundsWater-
most abundant inorganic compound in the body, 2/3’s of body
weight.
-Heat Capacity-Polarity/Solvent properties-Chemical reactivity-CushioningSalts-
ionic compounds, when dissolved, easily separate into their ions.
ElectrolytesAcids-
a substance that can release hydrogen ions (proton donor)
-have a sour taste
-can dissolve metals
-strong acids dissociate completely HCl  H+ + Cl-weak acids dissociate incompletely
H2CO3  H+ + HCO3-+ H2CO3
Bases-
a substance that picks hydrogen ions (proton acceptor)
-have a bitter taste
-feel slippery
-NaOH Na+ + OHAcid/Base
Exchange Reaction: Results in water and a salt
HCl + NaOH  H2O +NaCl
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pH:
Acid/Base Concentrations
-pH Scale- range from 0 to 14.
-based on the concentration of hydrogen and hydroxyl ions in
solution.
-1 is the most acidic, 14 the most basic, 7 is neutral.
-a change in 1 unit on the pH scale represents a 10-fold change in
hydrogen ion concentration.
-buffers- chemicals that can regulate a solution’s pH.
Organic Compounds- larger, complex compounds that contain carbon.
Carbohydrates-
-Usually have a ratio of 2 H’s to 1 O. Glucose C6H12O6 or Ribose
C5H10O5
-Classified as:
-Monosaccharides-Disaccharides-Polysaccharides-Carbohydrates are a good source of food energy for cells.
-During glycolysis, glucose is broken down into water and CO2, and
ATP, the high energy molecule used in most cellular reactions.
Lipids-
large compounds with carbon, hydrogen, and oxygen in various
proportions.
-Usually have a lot more C and H than O (tristearin C57H110O6)
-Do not easily dissolve in water, but in other lipids, alcohol, and
acetone.
-Classified into:
-Triglycerides (neutral fats)-saturated or unsaturated
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-body’s most abundant and concentrated source of
usable energy.
-Phospholipids-has polar properties
-found in cellular membranes
-Steroids-Cholesterol is most important of steroids
-Used to make vitamin D, some hormones, and bile
salts.
Proteins-
-over 50% of organic matter in the body
-multi-functional
-Building blocks of proteins are amino acids
-can range from 50 to 1000’s of amino acids in structure.
-The sequence in which the amino acids are placed determines the
structure and function of that specific protein.
-Fibrous or Structural Proteins-Globular or Functional ProteinsEnzymes-contain a specific structure that allows for
binding to a specific substrate. The enzyme
does not get used up during these reactions,
and is very specific in the reaction is helps to
carry out.
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Nucleic
Acids-
-make up genes, which carries the blueprint for life
-building blocks are nucleotides
-five different nucleotides:
-guanine, cytosine, adenine, thymine, uracil
-DNA contains GCAT, RNA contains GCAU
ATP-
-high energy molecule composed of C, O, H, N, P
-without ATP, no biologic reactions would take place
-energy is released when the outermost phosphate group broken
off, high energy is stored in that bond.
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