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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. Organic- compounds containing carbon (with hydrogen). Ex. Plants, animals
B. Inorganic- compounds that do not contain carbon. Ex. Air, water, minerals
V. Compounds Found in Living Things
Compound Atoms involved
Function Examples
Carbohydrates CHO
1:2:1
(fill in from next slides)
List examples
Lipids CHO (fill in from next slides)
List examples
Proteins CHON (fill in from next slides)
List examples
Nucleic Acids CHONP (fill in from next slides)
List examples
CHO
CHO
CHON
CHON
P
CHO
CHO
CHON
CHON
P
CHOCHOCHONCHONP
CHOCHOCHONCHONP
CHOCHOCHONCHONP
Carbohydrates
• A key source of energy• Building blocks are simple sugars-
monosaccharides (glucose & fructose)
• Disaccharides• Polysaccharides
Lipids
• Stored energy (mostly in animal-some 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
Biomolecules of Life: Foldable
Carbohydrates
C H O
Lipids
________
Proteins
________
Nucleic Acids
________
Bio
mole
cule
s of L
ife
FRONT
Picture of chemical structure
Common compounds
Uses
Key terms associated with biomolecule
Any other important information
Make sure you include the monomers that make up proteins
Make sure you include the monomers that make up nucleic acids
INSIDE
Terms that must be defined on your foldable…
• Saturated, unsaturated
• Monosaccharide, polysaccharide
• Nucleic acids
• Amino acids
• Monomer, polymer
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