A & P MACROMOLECULES (ORGANIC COMPOUNDS)
CARBOHYDRATES
Carbohydrates are organic compounds made of carbon, hydrogen and
oxygen atoms. Carbohydrates are a key source of energy and they are found
in most foods – especially fruits, vegetables and grains. The building blocks of
carbohydrates are simple sugars called monosaccharides, such as glucose and
fructose. Glucose serves as a main source of energy
in
humans and is converted to/stored as glycogen in
liver and muscle cells.
Numerous monosaccharides can bond with one
another to form large, complex molecules/polymers
called polysaccharides. Examples of
polysaccharides include starch, which is made by
plants, and helps store energy, and glycogen,
which is made by animals and stores energy in their
liver. Both are made of hundreds of linked/bonded
glucose molecules.
LIPIDS
Lipids are molecules that cannot dissolve in water. They are monomers of three
fatty acids bonded to a glycerol
molecule. Several of these monomers
can bond with one another to form
much larger polymers.
One example of a polymer of lipids is
phospholipids. Phospholipids help
form a cell’s membrane.
Steroids, which include cholesterol, are also found in cell membranes and make
Vitamin D. They also make the male and female hormones.
Fats are lipids that store energy. The most abundant type of fat is triglycerides.
Fats can protect organs in animals and allow for insulation (they help keep
animals warm).
PROTEINS
Proteins are the most abundant organic compound in organisms. A protein is a
large molecule formed by linked smaller molecules called amino acids. There
are twenty different known amino acids. It is important we eat foods rich in
proteins because we digest the proteins into their monomers, or amino acids,
then use those to build new proteins we need to survive. Although our cells are
able to make some of the amino acids we need, there are a few that we can
only obtain by eating certain foods.
Some polymers of proteins, called enzymes, are extremely important to an
organism’s metabolism. They help an
organism’s cells perform chemical
reactions necessary to keep it alive.
They are extremely important in helping
break down polymers obtained from the
food we eat into monomers that can
then pass through a cell’s membrane.