Download Proteins - Northwest ISD Moodle

Protein Basics
 Made of C,H,O, N
SPONCH
 Monomers = amino acids
- 20 different types of amino acids used to make
proteins
 Proteins are the polymer also called a polypeptide
Meet the monomer –Amino acid
 3 main parts
- Amino group NH2
- Carboxyl group COOH
- R group (side chain)
each of the 20 types
of amino acids have
a unique R group
Proteins form from chains of amino acids
Proteins vary in length – can be 1,000s of amino acids long
Protein
Proteins Shape
 A protein’s shape is determined by the order that
amino acids are joined in
 The shape of a protein determines its function
Hemoglobin
antibody
enzymes
polymerase
Protein Structure
Four Levels of Structure allow for any shape
2-28
Protein Structure – Primary Structure
 Primary structure is the order of the amino acids that
make up a protein.
- the interactions of the R groups on each amino acid
cause the molecule to bend and fold – different
arrangements create different shapes
- as a result- the order of
amino acids determines
the shape of the protein
- shape determines function
- changing a single amino acid can change a protein’s
shape.
Protein Structure- Secondary Structure
 The folding proteins often assume one of two general
shapes
– pleated sheets or an alpha helix these are the protein’s
secondary structure.
- hydrogen bonds between amino acids stabilize the
secondary structure
Alpha Helix
Protein Structure – Tertiary Structure
 The coiled or pleated structures continue to fold until
they form a complex three dimensional structure.
- most proteins are completed at this stage and are
fully functioning proteins.
Remember: Shape determines function
Protein Shape-Quaternary Structure
 Some more complex proteins are assembled from two
or more protein molecules.
- Insulin – 2 forms – 2 proteins or 6 proteins
- Hemoglobin – 4 proteins
Protein Functions
Proteins are the Worker Molecules of Living Things
 Enzymes - proteins that allow chemical reactions to





occur in living things
Antibodies – proteins that protect the body from
infection
Structure – cytoskeleton, hair, nails, muscles, spider
web, silk, feathers ,horns, hooves etc….
Hormones – chemical messengers
Cell membrane – proteins can act as channels through
the cell membrane
- receptor proteins found on membrane
transmit signals to the inside of cells
Hemoglobin – protein found in blood that carries oxygen
Proteins can be Denatured
 Denatured proteins are proteins that lose their shape
…
- if they lose their shape, they also lose their Function
- What can cause a protein to become denatured?
Exposure to: A Strong Acid
A Strong Base
Heat
An organic solvent: Alcohol or Acetone
- Denatured proteins can lose quaternary, tertiary and
secondary structure
- Primary Structure is left untouched
Denatured Proteins
Vocabulary for the Protein Pro
 Polypeptide
 Cell Membrane Proteins
 R – Group
 Hormones
 Peptide Bond
 Denatured Protein
 Primary Structure
 4 things that denature
 Secondary Structure
 Tertiary Structure
 Quaternary Structure
 Enzymes
 Antibodies
proteins