Carbohydrates and lipids/fats are a very
important part of our lives. They have many similarities
and differences among each other, which distinguish them from other
macromolecules.
Carbohydrates, which include sugar and their polymers, are used by organisms
for fuel and
building material. They come in many various forms going from simplicity to
complexity. The
simplest, monosaccharides, compose of single sugars whose parts are arranged
around
asymmetric carbons. They generally have a molecular formula that is a multiple
of CH2O.
Glucose, the most common monosaccharide, is of central importance in the
chemistry of life.
Energy is stored in glucose materials and extracts cells in the process of
cellular respiration.
When two monosaccharides join by covalently bonding through glycosidic linkage,
they form a
disaccharide, or double sugar. If more than two, such as hundreds and thousands
bond, they form
polysaccharides, or macromolecules.
There are two main types of polysaccharides; storage and structural. Starch and
glycogen are
used for storage. In plants, starch is mainly used because if it is
synthesized, the plant can stock
an abundance of sugar. Starch can be found in wheat, corn, rice, and other
grains. Glycogen, on
the other hand, is more extensively branched, therefore, it is stored by humans
and animals.
Cellulose and chitin are the structural polysaccharides. Cellulose is a tough
component of the
walls in a plant cell. Structure is important since that’s what organisms build
strong materials from.
In parallel cellulose molecules, the cell wall of a plant is held together by
bonds which are
arranged in microfibrils. These strong cables help build walls for plants and
humans. Chitin,
conversely, mainly deals with strengthening the arthropods’ exoskeletons.
The one thing all lipids have in common is the fact that they are hydrophobic.
The three families of
lipids are fats, phospholipids, steroids. Glycerol, a form of alcohol,
constructs fats when it is mixed with fatty acids who consist of a carboxyl
group on one end and hydrocarbon on the other. Three
fatty acids linked to a glycerol make up triacylglyceral. If the carbon atoms
composing the tail don’t
form any double bonds then a unsaturated fat is made. Respectfully, if one or
more bonds are
formed, the fat becomes saturated. Phospholipids are related to these fats, but
unlike
triacylglyceral, they have only two fatty acids. These lipids make up bi-layers
which form a
boundary between a cell and its external environment. The result of this simply
becomes the fact
that phospholipids are important to cell membranes. When a carbon skeleton
consists of four
interconnected rings, the third type of lipid, steroid, is built. Cholesterol,
a manufacturer of
steroids, is one reason that sex hormones are present in vertebrates. Because
of that, it has
important functions even though a high amount in the blood can contribute
towards
atherosclerosis.
Both carbohydrates and fats are an important part of our everyday diets. Almost
everything you
eat contains carbohydrates. For example, while looking at a nutrition label
from Basic 4, a
common cereal, I noticed that a serving of one cup contains 43g of total
carbohydrates. Only 14 of
those grams come from sugars, 4 come from fiber, and the remaining come from
other
carbohydrates. The fat make up is 3g in total; 0g unsaturated, 1g
polyunsaturated, and 1g
monounsaturated. This fat intake is only 4% of the daily value an average
person should have,
and the carbohydrates are 14% of the average. As you can tell, the advised
amount of polymers
to be consumed is rather high, therefore one conclusion can be drawn; they must
be important!