PROTEINS
Proteins
Composed mainly of
– Carbon
– Hydrogen
– Nitrogen
PROTEINS
• HAVE MANY FUNCTIONS!
• EX: CONSTRUCTION MATERIALS FOR THE
BODY, FOUND IN
– MUSCLES
– SKIN
– BLOOD.
Amino Acids
of Protein
• Made up of smaller units called
AMINO ACIDS
• Our bodies contain thousands of
different proteins. All are made
from about 20 different amino acids.
• Amino acids differ ONLY in the
type of R Group they have.
– causes different shapes and different
functions
•Amino Acids bond to form
a DIPEPTIDE, during D. S.
• Form a covalent bond,
called a PEPTIDE BOND.
Amino Acids
of Protein
•Many amino acids can
bond, forming a long chain
called a POLYPEPTIDE.
A protein is a
polypeptide
Amino Acids
of Protein
•Proteins are composed of
one or more polypeptides.
•Some proteins are very
large molecules, containing
hundreds of Amino Acids.
Shape Determines
Function
• Proteins are often bent and
folded because of bonding
among amino acids
• Denaturing Proteins
– Caused by change in
temperature, pH
• Cooking an egg
• Certain hair styles
4 Levels of Protein Structure
• Primary – sequence of amino acids
• Secondary – H bonds between A.A. cause
coil or pleats.
• Tertiary – Protein folds more
• Quaternary – made up of different
subunits all put together
Enzymes are types of
Proteins
• ENZYMES – speed up
chemical reactions (act as a
catalyst!) by lowering the
amount of energy it takes for
the reaction to occur.
(ACTIVATION ENERGY)
• Enzymes are shape-specific. Substrate
molecule must fit the active site.
Enzymes
•After the reaction, the product
is released, enzyme is
unchanged, so it can be used
many times.
REVIEW
a. Substrate binds to Enzyme
b. Chemical Reaction
c. Products Formed; Enzyme Unchanged