Transcript Ch. 5.3: LIPIDS

Ch. 5.4: Proteins
Objectives:
1)List the functions of proteins.
2)Describe the structure of amino acids and proteins.
3)Describe factors that influence protein shape.
Vocabulary:
Protein
Amino acid
Polypeptide
Denaturation
Protein Functions
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Provide structure for hair, fur
Make up muscles
Long term nutrient storage
Antibodies (immune responses)
Enzymes - facilitate chemical reactions in cells/body
Monomer Units: Amino Acids
20 naturally occurring
All have: Amino group (-NH2); Carboxyl
group (-COOH); and Hydrogen bonded to a
central carbon
R group = side group; different for each
a.acid
tyrosine
Polymers: Polypeptides
 Amino acids
join to build
polypeptides
through
DEHYDRATION
SYNTHESIS.
 Peptide bonds
= covalent
bonds that link
amino acids
Polypeptide Shape & Structure
 Polypeptide = long chain of
amino acids
 1 or more polypep. chains =
Protein
Shape based on…
1. Amino acid sequence (interxns
b/w a.acids)
2. Environment
a. Hydrophobic parts on
interior; Hydrophilic parts
on exterior
b. Temperature & pH
Denaturation =
Proteins UNRAVEL/UNFOLD in
response to changes in TEMP.,
pH, etc.
(interfere with weak bonds
that give proteins their shape).
Proteins stop functioning!
Protein shape is important to
fxn!