14.1 – 14.4
By: Sheyanne Wertz and Alexis Reid
Period C
14.1: PROTEINS
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Proteins are the most important biological
compound
There are many functions of proteins
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Structure- structural protein make up
animals. Two important structural proteins
are collagen and keratin
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Catalysis- every reaction that takes place in
the living organisms are catalyzed by proteins
called enzymes.
FUNCTIONS OF PROTEINS
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Movement- Every time we move we use muscles.
Muscles are made up of protein molecules called
myosin and actin.
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Transport- Hemoglobin is a protein in the blood that
transports oxygen from the lungs to cells and co2
from the cells to the lungs.
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Hormones- Many are proteins. Such as insulin ,
erythropoietin, and human growth hormones.
MORE FUNCTIONS
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Protection- If a foreign protein gets in our
body, our body will make our own protein
called antibodies to counteract it. The
antibody production helps fight diseases.
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Storage- Proteins store materials
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Regulation- Proteins control genes, regulating
the kind of protein synthesized in a cell, but
also dictate when such manufactures take
place
14.1 CONTINUED
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A typical cell has 9,000 different proteins
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The entire human body has 100,000 proteins
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Proteins can be classified in two different groups
 Fibrous protein- Insoluble in water used for
structural purposes
 Globular proteins- More or less soluble in
water used for nonstructural purposes.
14.2
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Amino acids are organic compounds containing
an amino and a carboxylic acid group
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Proteins are chains of amino acids
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20 common amino acids found in proteins
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They are known as the alpha amino acids
14.2 CONTINUED
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They are classified by their side chains
 Nonpolar - Hydrophobic
 Polar but neutral - Hydrophilic
 Acidic - Hydrophilic
 Basic - Hydrophilic
All amino acids in human tissue are L- amino
acids
They are tetrahedral structures
14.3
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Amino acids in the solid state, as well as in
water carry both positive and negative charges.
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They are called zwitterions
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German word “zwitter” means hybrid
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They are ionic compounds
14.3 CONTINUED
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The pH at which the number of positive
charges equals the number of negative charges
is the isoelectric point of an amino acid or
protein.
Amino acids are zwitterions
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High melting points, fairly soluble in water
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Zwitterions with different pH levels
14.4
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Amino acids are almost identical besides their
side chains
The side chain is what gives the amino acid its
unique nature and its particular properties
Some amino acids have charged side chains
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Amino acid side chain
14.4 CONTINUED
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Cysteine is a special amino acid because its side
chain can form disulfide bridges with another
cysteine
Aromatic amino acids are important
physiologically
Precursors of neurotransmitters
 Absorb ultraviolet light
 Allows us to easily measure and locate them
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Disulfide bond found in cystine