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Section 14.1-14.4
By: Kellen Kane & Ian Snyder
 The most important of all biological compounds are
proteins
 Structure: Proteins are the chief constituents of skin,
bones, hair, and nails for animals. Collagen and keratin
are two important structural proteins.
 Catalysis: All reactions that take place in living
organisms are catalyzed by proteins called enzymes.
Without enzymes, the reaction would be so slow, that
it would be useless.
 Catalysis: All reactions that take place in living
organisms are catalyzed by proteins called enzymes.
Without enzymes, the reaction would be so slow, that
it would be useless.
 Movement: Muscles are made up of protein
molecules called myosin and actin which allows you to
move.
 Transport: Many proteins perform transportation
duties. Molecules are also transported across the cell
membrane by proteins.
 Example of transport: Hemoglobin which is a protein
in the blood, carries oxygen from the lungs to the cells
where it is used, and then takes the carbon dioxide
from the cells to the lungs.
 Hormones: A lot of hormones are proteins, including
erythropoietin, insulin, and human growth hormone
(HGH).
 Protection: Your body makes its own proteins called
antibodies to counteract foreign protein and fight
diseases. Another protective function is called
fibrinogen which is blood clotting. Without blood
clotting, we would bleed to death from any small cut.
 Storage: Proteins store material similar to the way that
starch and glycogen store energy.
 Casein and milk ovalbumin in eggs and Ferritin stores
iron
 Regulation: They control what kind of proteins are
synthesized in cells.
 They are categorized into two major types:
 Fibrous proteins: insoluble in water and are used for
structural purposes.
 Globular proteins: less soluble in water and used for
nonstructural purposes.
 Proteins are chains of amino acids and an amino acid
is an organic group.
 contains an amino group and a carboxyl group.
 Many amino acids are synthesized by chemists but
there are about 20 that are common in nature.
 The 20 acids that are found in nature are called the
alpha amino acids.
 Has an amino group and a carboxyl group
 Amino acids are classified into four groups depending
on what R groups are found in it.
 Nonpolar
 Polar but neutral
 Acidic
 Basic
 Amino acids are chiral since they have four different
groups
 The carbon acts as the stereocenter
 L-isomers are the most common
 D-amino acids are very rare
 Zwitterions are compounds that have a positive charge
on one atom and a negative charge on another
 Amino acids are zwitterions in both water solution and
in solid state
 The addition of a strong acid changes amino acids into
a positive ion
 The addition of a strong base makes the amino acid a
negative ion
 The isoelectric point (pI) is when an amino acid has an
equal amount of positive and negative charges
 15 out of the 20 amino acids found in nature have an
isoelectirc point near 6
 Aqueous solutions of amino acids are buffer solutions
 The side chain of an amino acid is what determines
characteristics
 The function of amino acids in proteins are determined
by side chains
 Cystine
 Dimer of cysteine
 Disulfide bond
 Presence of Carboxyl group
 Forms Carboxylate ion
 Aromatic
 Allow us to locate and measure proteins
 Proteins are molecules made of amino acids bonded
together by peptide bonds
 Proteins have many functions
 Structural
 Enzymatic
 Carrier
 Storage
 Protective
 Hormonal
 Amino acids are organic compounds containing an
amino and carboxylic acid group
 The 20 amino acids found in nature are classified by
their side chains
 Nonpolar
 Polar but neutral
 Acidic
 Basic
 Amino acids in both aqueous and solid state carry
both positive and negative charges, called zwitterions
 The pH at which the number of positive charges equals
the number of negative charges is the isoelectric point
 Amino acids are nearly identical in most ways, aside
from their side chains
 Side chains give the amino acids its properties
 Some amino acids have charged side chains