BIOCHEMISTRY CH 2 Outline/ Study Guide
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Carbohydrates - molecules of Carbon, Hydrogen and Oxygen
Monomer = simple sugars (monosaccharides)
Examples = glucose, galactose, fructose - all C6H12O6
Disaccharides - combinations of two monosaccharides (simple sugars)
Examples = sucrose, maltose, lactose - all C12H22O11
Polysaccharides - long chains of sugars
Example = starch - long looping chains of glucose
cellulose – makes up cell wall in plants

Lipids (Fats) - molecules of fatty acids and glycerol
Monomer = glycerol plus three fatty acids
Saturated Fat = fatty acids loaded with hydrogens are saturated, single bonds, solid at
room temp
EXAMPLE: foods from animals - meat and dairy
Unsaturated = fatty acids with double bonds and less hydrogens are unsaturated, liquid at
room temp
EXAMPLE: partially hydrogenated vegetable oil in foods

Proteins - molecules of amino acids
Monomer = Amino Acids
There are 20 different amino acids in biological compounds
Proteins are also known as polypeptides

Nucleic acids
DNA = deoxyribonucleic acid
Backbone is made of sugar (deoxyribose - 5 carbon) and phosphate
Monomer = nucleotide (made up of sugar + phosphate + nitrogenous base)
Four bases:
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
Base pairing - hydrogen bonding holds two strands together
A-T
C -G
Strands twisted in a double helix
RNA = ribonucleic acid
Backbone is made of sugar (ribose - 5 carbons) and phosphate
Monomer = nucleotide (made up of sugar + phosphate + nitrogenous base)
Four bases:
Adenine (A)
Uracil (U)
Cytosine (C)
Guanine (G)
base pairing on DNA template
A-U
C -G
strands single - not a double helix
SECTION 3-1, WATER
POLARITY
1. Many of Water's Biological Functions stem from its Chemical Structure.
2. In the Water Molecule, H2O, the Hydrogen and Oxygen Atoms SHARE Electrons to form a Covalent Bond,
but these atoms DO NOT Share the electrons Equally.
3. The Oxygen Atom, because of it 8 Protons versus Hydrogen's 1 Proton, PULLS the Shared Electrons towards
its Nucleus and AWAY from the Hydrogen Atom. As a result, the Electrical Charge is UNEVENLY
Distributed in the Water molecule. (Figure 3-1)
4. Although the TOTAL Electrical Charge on a Water Molecule is NEUTRAL, the
region of the molecule where the Oxygen Atom is located has a Slightly NEGATIVE
Charge, while the regions of the molecule where each of the Two Hydrogen Atoms are
located have a Slightly POSITIVE Charge.
5. Because of this UNEVEN PATTERN of CHARGE, Water is called a POLAR
MOLECULE. Molecules with a Slightly Negative End and a Slightly Positive are called
Polar Molecules.
6. It is this Polar Nature that makes Water VERY EFFECTIVE in Dissolving many other substances.
7. Water Dissolves Other Polar Substances including, Sugars, some Proteins, and Ionic Compounds such as
Sodium Chloride, NaCl.
HYDROGEN BONDING
1. The Polar Nature of Water also causes Water Molecules to be attracted to one
another or stick together.
2. The Type of ATTRACTION that Holds TWO Water Molecules Together is
called HYDROGEN BONDING. (Figure 3-3)
3. A POSITIVE REGION OF ONE MOLECULE IS ATRACTED TO THE
NEGATIVE REGION OF ANOTHER MOLECULE.
4. A Hydrogen Bond is a WEAK Bond that can be easily broken.
5. The Hydrogen Bonds in Water exert a significant Attractive Force, causing
Water to Cling to Itself (Cohesion) and to other Surfaces (Adhesion).
6. An Attractive Force BETWEEN PARTICLES OF THE SAME KIND is known as COHESION. This
causes Water to look like it is Climbing up the side of a Glass.
7. ADHESION is the Attractive Force BETWEEN UNLIKE SUBSTANCES.
8. Together, Adhesion and Cohesion enable Water Molecules to MOVE UPWARD through narrow tubes
Against the PULL OF GRAVITY. This Property of Water is known as CAPILLARY ACTION. This is what
allows Plants to move Water from their Roots to their Leaves.