Download Carbon- Based Molecules

Carbon atoms have unique
bonding properties
I. Carbon is Often Called The Building Block of Life
a. Carbon atoms are the basis of most molecules
that make up living things.
b. Carbon is so important because its atomic
structure gives it bonding properties that
unique among elements.
i.
ii.
Carbon has four unpaired electrons in its outer shell, so it can
bond with up to four other atoms, including other atoms. It acts
like an “intersection”.
Because of carbon’s ability to form four covalent bonds, it can
have three basic structures- straight chains, branched chains,
and rings.
c. Small molecules are subunits of an entire
molecule, like links in a chain. Each sub unit is
called a monomer.
d. When monomers are linked, they form a
polymer (chain). A polymer is a large molecule,
or macromolecule, made of many monomers
bonded together.
Four main types of carbon-based
molecules are found in living things
I.
Carbohydrates
a.
These are molecules composed of carbon, hydrogen,
and oxygen, and they include sugars and starches.
b. Main function- Can be broken down to provide
a source of usable energy for cells.
c. Function- Can be used to give structure to plant
cells, fungal cells, and the exoskeletons of some
invertebrate animals.
d. Monomer: Simple sugars. Fructose and
glucose are both 6-carbon simple sugars.
These are also known as monosaccharides.
e.
Polymer:
i.
Polysaccharides such as starch (stored by plants which
can then be broken down as a source of energy) and
glycogen (known as “animal starch” which is stored in
the liver of animals and broken down for energy as
well).
ii. Cellulose is a polymer of glucose monomers that has a
straight, rigid structure and gives support to plant
cells. The long, stringy fibers in celery are cellulose
fibers.
Polymer (starch)
Starch is a polymer of
glucose monomers
that often has a
branched structure.
Polymer (cellulose)
monomer
Cellulose is a polymer
of glucose monomers
that has a straight,
II.
Lipids
a.
b.
These are nonpolar molecules that are made up
of chains of carbon atoms bonded to oxygen
and hydrogen atoms.
Fats, oils, cholesterol, and waxes are examples.
c. Main function: Broken down as a source of
usable energy for cells.
d. Function: Part of a cell’s structure.
e. Function: Insulation.
f. Monomer: Three fatty acids bonded to
glycerol, called triglycerides.
Triglyceride
g. All cell membranes are made mostly of a type
of lipid called a phospholipid.
h. Cholesterol is a lipid that has a ring structure,
and although you hear about the dangers of
eating foods that contain a lot of cholesterol,
your body actually needs a certain amount of it
to function.
i.
ii.
membranes.
Your body uses it to make steroid hormones such as
Makes up cell
testosterone and estrogen.
III. Proteins
a.
These are the most varied carbon-based
molecules in organisms.
b. Main Functions: Many! Speed up reactions,
function in the immune system, carry
oxygen, build structures of the body.
Amino acids
c.
Monomer. These are molecules
that contain carbon, hydrogen, oxygen, nitrogen, and
sometimes sulfur.
d.
Organisms use
different amino acids to build
proteins. Your body can make 12 of the amino acids, and
you can get the others from foods you eat such as
20
meat, beans, and nuts.
e. Proteins differ in the number and order
of amino acids. The specific sequence
determines a protein’s structure and
function.
f.
Hemoglobin in red blood cells transports oxygen.
The structure of hemoglobin depends on hydrogen
bonds between specific amino acids. Just one amino
acid change causes red blood cells to have the
curved shape of sickle-cell anemia.
Hemoglo
bin
hydrogen bond
IV.
DNA
Nucleic Acids
Store
transmit hereditary
a.
Main function:
and
information, which makes proteins.
b.
Monomers, which are made up
of a sugar, a phosphate group, and a nitrogen
containing base.
c.
Examples of nucleic acids:
Nucleotides
DNA and RNA.
RNA