The Chemistry of Life
The Chemistry of Life
• It has been estimated that over 200,000
chemical reactions occur in the cells of our
body. All of these chemical reactions are
referred to as our metabolism. Metabolic
reactions can be either:
a) Catabolic – materials are broken down
Or
b)Anabolic – materials are built
• Organic chemistry is the area of chemistry
that refers to compounds containing
carbon. All living things are organic.
Organic compounds can be broken down
within cells for energy or linked together to
form long chains necessary for life.
• Living things are composed of non-living
chemicals. Proteins, carbohydrates, lipids
(fats), nucleic acids, vitamins, and
minerals are all chemicals of living things.
All of the macromolecules (big molecules)
are mostly made up of carbon, hydrogen,
oxygen, and sometimes nitrogen. The
bulk of what we eat is made up of
carbohydrates, proteins, and fats.
Vitamins and minerals are also required,
but in much smaller amounts.
1) Carbohydrates
• Carbohydrates are the body’s most
important source of energy!! The human
body is not capable of making these vital
chemicals by itself and must rely on plant
sources for this important nutrient.
What are Carbohydrates?
• Carbohydrates are sugars or starches and
have an –ose ending. These are chains of
sugar molecules joined end to end like
cars of a train. Cellulose is a
polysaccharide found in plants. Animals
are not able to digest and absorb this
starch and it travels through the digestive
system relatively unchanged. We call this
fiber.
•There are 3 different forms these chains can
be found in:
• a) Monosaccharidescontain only one sugar in
the chain (glucose)
• b) Disaccharides- contain
only two sugars in the
chain (sucrose)
• c) Polysaccharides –
many sugars in the chain
(starch)
• Animals store carbohydrates in the tissues
in the form of glycogen. The sugars from
the foods we eat gets either gets used up
as fuel for the cells or stored for future
use. This stored sugar (glycogen) is stored
for a short time, minutes or hours. If it is
not used up, it will be converted into long
term storage as fat in adipose (fat) cells.
2) Proteins
• Proteins are the structural component of
cells. They are present in mitochondria,
ribosomes, muscles, skin, antibodies,
enzymes, etc… Proteins are essential for
the building, repair and maintenance of
cell structure. They are composed of 20
different amino acid building blocks.
• Proteins are essential to our diet. There
are 8 amino acids that the body cannot
synthesize called essential amino acids.
These must be obtained from your food.
3) Lipids
• Lipids are also known as fats (solids at
room temperature) or oils (liquid at room
temperature). Lipids are compounds
which are insoluble (do not dissolve) in
water. Fats are concentrated packages of
energy containing more than twice as
much energy as the same amount of
carbohydrates.
Function of Lipids
a) as energy storage –
glycogen builds up
resulting in conversion to
long-term storage
molecule: fat
b) makes up cell membranes
- phospholipids
c) cushion for organs
d) carrier and storage for
vitamins
4) Nucleic Acids
Nucleic acids are the hereditary
material found inside the chromatin in the
nucleus. DNA (deoxyribonucleic acid) is
made up of this type of nutrient. Nucleic
acids are nitrogen-containing compounds
and are composed of nucleotides. Just
like amino acids are the building blocks of
proteins, nucleotides are the building
blocks of nucleic acids.
You are what you eat….
• When we consume food, we are eating the
DNA from a variety of sources. Our
digestive system cuts apart the
nucleotides from the foreign DNA. These
single nucleotides (which are the same as
in human DNA) are used to make new
DNA for our new cells that are always
under construction. So, you REALLY “are
what you eat!”
5) Vitamins and Minerals
• Vitamins and minerals are required in only
small amounts and help in chemical
reactions in the body. Vitamins and
minerals are essential for good health.
Vitamins and minerals boost the immune
system; support normal growth and
development, and help cells and organs
do their jobs.
Rickets
• Most cases of rickets
are caused by a lack of
vitamin D. Vitamin D
helps the bones absorb
calcium and phosphorus
from food. When your
child does not get
enough vitamin D, his or
her bones do not get
those necessary
nutrients that makes
bones strong.
Osteoporosis
• Osteoporosis is a loss in bone density due
to a prolonged deficiency of calcium.