Transcript Fats and Proteins

Fats and Proteins
The good, the bad and the others
Fats
Fats are a sub-group of compounds known as lipids that are found in the
body and have the general property of being hydrophobic (meaning they
are insoluble in water). Fats are also known as triglycerides, molecules
made from the combination of one molecule of glycerol with three fatty
acids, as depicted below:
Glycerol
3 Fatty Acids
(where R
represents a
long C-C-C
chain)
Fat (triglyceride)
(where R, R' & R"
may or may not be
the same)
Fats can be classified as either saturated or unsaturated
depending on the structure of the long carbon-carbon chains
in the fatty acids (the R's in the diagram above).
Fats that contain no double bonds in their fatty acid chains are referred
to as saturated fats. These fats tend to be solid at room temperature,
such as butter or animal fat. The consumption of saturated fats
carries some health risks in that they have been linked to
arteriosclerosis (hardening of the arteries) and heart disease.
Unsaturated fats contain some number of double bonds in their
structure. These fats are generally liquids at room temperature
(fats that are liquid at room temperature are referred to as oils).
Unsaturated fats can be either polyunsaturated (many double
bonds) or monounsaturated fats (one or few double bonds).
Recent research suggests that the healthiest of the fats in the
human diet are the monounsaturated fats, such as olive oil and
canola oil, because they appear to be beneficial in the fight
against heart disease.
Proteins

Proteins are polymers of
amino acids. While there are
hundreds of thousands of
different proteins that exist in
nature, they are all made up
of different combinations of
amino acids. Proteins are
large molecules that may
consist of hundreds, or even
thousands of amino acids.
Amino acids all have the
general structure:

General Structure of an
Amino Acid

When 2 amino acids bond together, the two ends of
nearby amino acids (shown above in red) are released
and the carbon (called a carboxyl) end of one amino
acid bonds to the nitrogen end of the adjacent one
forming a peptide bond, as illustrated below:
3-dimensional structure of proteins
Representation of the
1° structure
(amino acid sequence
- illustrated with
different colors),
2° structure (coiling) &
3° structure (folding) of
a protein
Polymers

The field of polymers is so vast and the applications so varied,
that it is important to understand how polymers are made and
used. Since there are over 60,000 different plastics vying for a
place in the market, knowledge of this important field can truly
enrich our appreciation of this wonder material.
Companies
manufacture over 30 million tons of plastics each
year, and spend large sums on research, development, and more
efficient recycling methods. Below we learn some of the
scientific principles involved in the production and processing of
these fossil fuel derived materials known as polymers

Polymerization Reactions
The chemical reaction in which high molecular mass
molecules are formed from monomers is known as
polymerization. There are two basic types of
polymerization, chain-reaction (or addition) and stepreaction (or condensation) polymerization.
Chain-Reaction Polymerization
One of the most common types of polymer reactions is
chain-reaction (addition) polymerization. This type of
polymerization is a three step process involving two chemical
entities. The first, known simply as a monomer, can be
regarded as one link in a polymer chain. It initially exists as
simple units. In nearly all cases, the monomers have at least
one carbon-carbon double bond. Ethylene is one example of a
monomer used to make a common polymer.

The other chemical reactant
is a catalyst. In chain-reaction
polymerization, the catalyst
can be a free-radical peroxide
added in relatively low
concentrations. A free-radical
is a chemical component that
contains a free electron that
forms a covalent bond with
an electron on another
molecule. The formation of a
free radical from an organic
peroxide is shown below:
Everyday Polymers and their uses
Resin
Code
Common Uses
Examples of Recycled
Products
Soft drink bottles, peanut butter jars, salad dressing bottles, mouth
wash jars
Liquid soap bottles,
strapping, fiberfill for winter
coats, surfboards, paint
brushes, fuzz on tennis balls,
soft drink bottles, film
High density Polyethylene (HDPE)
Milk, water, and juice containers, grocery bags, toys, liquid
detergent bottles
Soft drink based cups, flower
pots, drain pipes, signs,
stadium seats, trash cans, recycling bins, traffic barrier
cones, golf bag liners, toys
Polyvinyl Chloride or Vinyl (PVCV)
Clear food packaging, shampoo bottles
Floor mats, pipes, hoses,
mud flaps
Low density Polyethylene (LDPE)
Bread bags, frozen food bags, grocery bags
Garbage can liners, grocery
bags, multi purpose bags
Ketchup bottles, yogurt containers, margarine, tubs, medicine
bottles
Manhole steps, paint
buckets, videocassette
storage cases, ice scrapers,
fast food trays, lawn mower
wheels, automobile battery
parts.
Video cassette cases, compact disk jackets, coffee cups, cutlery,
cafeteria trays, grocery store meat trays, fast-food sandwich
container
License plate holders, golf
course and septic tank
drainage systems, desk top
accessories, hanging files,
food service trays, flower
pots, trash cans
Resin Name
Polyethylene Terephthalate (PET
or PETE)
Polypropylene (PP)
Polystyrene (PS)