Transcript CHEMISTRY OF LIFE

CHEMISTRY OF LIFE
BIOLOGY-THE STUDY OF LIFE
The Chemistry of Life
I.
Organization of Atoms
II.
Bonds
III.
Water Molecules
IV.
Classification of
Compounds
V.
Compounds found in
living things.
I. Organization of Atoms
A. Atom- the smallest unit of matter that cannot
be broken down by chemical means.
1. Protons- positive charge, located in the
nucleus.
2. Neutrons- no charge, located in the nucleus.
3. Electrons- negative charge surrounding the
nucleus in a cloud.
I. Organization of Atoms
B. Element- a pure substance made of only one
kind of atom.
C. Compound- a substance made of the joined
atoms of two or more different elements. Ex.
NaCl (Sodium Chloride)
D. Molecule- a group of atoms held together by
covalent bonds.
I. Organization of Atoms
E. Ion- an atom or molecule that has gained or
lost one or more electron. Ions have an
electric charge because they contain an
unequal number of electrons and protons.
1. Positive charge- atom that has lost an
electron.
2. Negative charge- atom that has gained
electrons.
II. Bonds
A. Ionic Bonds- when ions of opposite charges
interact. Ex. Sodium chloride—an atom of
sodium is unstable—only 1 electron in the outer
shell (valence electron). An atom of chlorine is
unstable because it has 7 valence electrons.
The atoms are readily attracted to each other.
II. Bonds
B. Covalent bonds – form when two or more
atoms share electrons. (very strong bonds -“super glue”)
C. Hydrogen bonds – a weak chemical attraction
between polar molecules. Ex. A water
molecule—H2O.
III. Water Molecules
A. The electrons in a water molecule are
shared by oxygen and hydrogen
atoms.
B. A water molecule has positive and
negative ends, thus polar.
III. Water Molecules
C. Particles are able to dissolve readily in
water due to its polarity. Thus, the
“universal solvent”.
III. Water Molecules
D.
Cohesion – an attraction between
substances of the same kind. The hydrogen
bonds between water molecules cause the
cohesion of liquid water molecules at the
surface of water (like holding hands).—this
attractions is “surface tension”
III. Water Molecules
E.
Adhesion – attraction
between different
substances. Ex. Water
molecules moving
upward through the stem
of a plant.
III. Water Molecules
F. Evaporative cooling – Water heats
more slowly and retains heat longer.
Organisms release heat through water
evaporative cooling (sweat).
IV. Classification of Compounds
A. Organiccompounds
containing carbon
(with hydrogen).
Ex. Plants, animals
B. Inorganiccompounds that do
not contain carbon.
Ex. Air, water,
minerals
V. Compounds Found in Living
Things
Compound
Atoms
Function
Examples
(fill in from
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List
examples
Lipids
CHO
1:2:1
CHO
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Proteins
CHON
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Nucleic Acids
CHONP (fill in from
List
examples
List
examples
List
examples
involved
Carbohydrates
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CHO
CHO
CHON
CHONP
Carbohydrates
• A key source of energy
• Building blocks are simple sugarsmonosaccharides (glucose &
fructose)
• Disaccharides
• Polysaccharides
Lipids
• Stored energy
(mostly in animalsome plant seeds)
• Nonpolar molecules
• Fats, oils, steroids,
and waxes
• Phospholipids—
make up the lipid
bilayer of cell
membranes
Proteins
• Important for structural functions
– Skin, ligaments, tendons, muscles, hair
• Anitibodies, hemoglobin, hormones, enzymes
• Building blocks are amino acids
– 20 different amino acids are found in living
things
Nucleic Acids
• Contain all genetic, hereditary
information
• DNA, RNA
• Building blocks are nucleotides