MACROMOLECULES
Proteins
Monomers and Polymers

What are macromolecules?
•
Large organic molecules
•
Made up of repeating units
–
Monomers
•
Monomers of proteins
–
Amino acids
•
Sequence of amino acids in a protein determines structure and function

Formation of Macromolecules
•
Monomers of macromolecules are formed through Dehydration Synthesis
–   also known as a Condensation Reaction
–
Bonds between monomers formed when water is removed (OH + H + -> H
2
)

DNA and Amino Acid Sequence

Amino Acids

All About Amino Acids h"p://www.hcc.mnscu.edu/programs/dept/chem/V.27/amino_acid_structure_2.jpg

Amino Acids & Peptide Bonds

Primary Structure
•
Determined by sequence of amino acids within a protein-most basic structure
•
Amino acids:
–
Linked by peptide bonds to form long chains
–
Peptide bonds formed through dehydration synthesis between
Amino  acids   aa1   aa2   aa3   aa4   aa5
Pep3de  bonds

Secondary Structure

Tertiary Structure
•
Third level of protein structure
•
Determined by bonding interactions between the side chains of the amino acids
•
Bonds result in formation of folds, bends, and loops

Quaternary Structure
•
Formed from multiple tertiary proteins
•
Collagen is a protein shown to the left
•
Three helices form the structure of collagen

Levels of Protein Structure

Proteins
•
Macromolecules
–
Made up of chains of amino acids
–
There are approximately 20 amino acids found in life on earth
–
Sequence of amino acids in proteins
•
Encoded in sequence of nitrogen bases (adenine, cytosine, guanine, and thymine) in DNA
•
Messenger RNA transcribed from DNA
•
Messenger RNA is translated into specific protein
–
Unique sequence of amino acids
–
Unique structure (folding pattern)
–
Unique function

Functions of Protein
•
Enzymes – regulation of cellular function
•
Hormones – chemical messengers
•
Transport – hemoglobin in RBCs
•
Movement – muscle (skeletal & smooth)
•
Structure – keratin and melanin
•
Communication – cellular receptors

Proteins are critical to structure and function

Proteins make up
Skin and Nail
Protein in skin cells Protein in nails

Proteins and Antibodies
•
Antibodies:
•
are proteins
•
production stimulated by foreign substances in the body
•
bind to foreign cells, proteins, etc.

Protein and Enzymes
•
Many proteins function as enzymes
•
Speed up chemical reactions within the cell
•
Critical for digestion
•
Function as the “ work horse ” of the cell

Protein and Hormones
Non-steroid Hormones
•
Consist of protein
•
Act as chemical messengers
•
Carried by blood
•
Bind to external cellular receptors (on cell membrane)

•
Viewing  protein  structures  using
Go  to
UCSF  Chimera
•   Select   “ Download ”  in  the  leH  Menu
•   Download  and  install  a  version  for  your  OS
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