Biology
Unit Three/Four
Organic Molecule Poster Project

Monomers and Polymers:
Life is made up of organic compounds of diverse size and structure. The large molecules are usually
polymers made up of chains of smaller, simpler molecules which are monomers.

Disaccharides,
Oligosaccharides,
and
Polysaccharides
Proteins and
Polypeptides
Oils, Waxes,
Fats, and others
DNA, RNA, ATP,
and others
Monosaccharaides
Amino Acids
None
Nucleotide
Carbohydrates:
As their name implies carbohydrates are composed of the elements of water and carbon so their
formula approximates to a multiple of CH2O. Most of the dry weight (biomass) of plants is
carbohydrate of one kind or another. All carbohydrates are polar and most are commonly known as
sugars. Sugars are freely soluble in water.
Carbohydrates are responsible for many structural components of
life but, perhaps most importantly, carbohydrates provide quick
energy. Plants make glucose in the photosynthetic process. Glucose
is a monosaccharide with the chemical formula C6H12O6.
Monosaccharides join by a glycosidic bond to form disaccharides.
This bond is made by removing the elements of water from two
sugars in a reaction called dehydration or condensation reaction.
Glycosidic bonds can be broken by re-introducing the elements of
water in a process known as hydrolysis
Polysaccharides are made up by joining hundreds
of monosaccharides by glycosidic bonds. The
most common food reserve in plants is starch
which is easily digestible. Cellulose is a similar
polysaccharide but is not easily digestible due to
the OH position at the terminus. The glycosidic
bonds of starch and cellulose are differentiated as
α-1,4 bonds for starch and β-1,4 bonds for
cellulose. Humans and most animals have
hydrolytic enzymes that can break down starch but lack an enzyme to break down cellulose.
Fungal cell walls and insect exoskeletons are
made of chitin, another polysaccharide made of
many glucose molecules joined together in a
dehydration reaction with glycosidic bonds.

Lipids:
Lipids are fatty substances with long
hydrocarbon chains and often ester linkages
somewhere in the molecule. There are three
classes of lipids in plants. The simplest are
the triglycerides or fats in which three fatty
acids are attached to a glycerol molecule by
ester bonds. These are the most energy-rich
form of food reserve (for plants and for us). Plants tend to accumulate fats only when it is important to
pack a lot of energy into a small space, such as a seed.
Membrane lipids are similar to triglycerides except
that one of the fatty acids is replaced by a polar group
such as a sugar in a glycolipid or a phosphate
compound in a phospholipid. The combination of a
polar head group and a non-polar tail is important
in membrane structure and function.

Proteins
Proteins are large biological molecules
consisting of one or more chains of amino
acids called polypeptides. A polypeptide is a
single linear polymer chain of amino acids
bonded together by peptide bonds between
the carboxyl (COOH, C-terminus) and amino
groups (NH2, N-terminus) of adjacent amino
acids. The sequence of amino acids in a
protein is defined by the sequence of a gene,
which is encoded in the genetic code.
Proteins are large complex molecules, much larger than carbohydrates and lipids, and more complex
than nucleic acids. Their complexity is owed to two reasons; first is the chemical composition which
differs based on the side chain, represented by an “R”. The second reason for the complexity is the three
dimensional structure created in a complex series of folding that creates the final protein.
Many proteins are enzymes that catalyze biochemical reactions and are vital to metabolism. Proteins
also have structural or mechanical functions, such as actin and myosin in muscle and the proteins in the
cytoskeleton, which form a system of scaffolding that maintains cell shape. Other proteins are important
in cell signaling, immune responses, cell adhesion, and the cell cycle. Proteins are also necessary in
animals' diets, since animals cannot synthesize all the amino acids they need and must obtain essential
amino acids from food. Through the process of digestion, animals break down ingested protein into free
amino acids that are then used in metabolism.

Nucleic Acids
Nucleic acids are large biological molecules essential for all known forms of life. They include DNA
(deoxyribonucleic acid) and RNA (ribonucleic acid) as well as a number of derivatives used in energy
transport, like ATP (adenosine triphosphate). Nucleic acids are found in abundance in all living things,
where they function in encoding, transmitting and expressing genetic information.
The term nucleic acid is synonymous with polynucleotide. All living
cells contain both DNA and RNA, while viruses contain either DNA or
RNA, but usually not both. The basic component of biological nucleic
acids is the nucleotide, each of which contains a pentose sugar
(ribose or deoxyribose),
a phosphate group, and
a nucleobase.
Non-standard
nucleosides are also
found in both RNA and
DNA and usually arise
from modification of the standard nucleosides within the DNA molecule. Transfer RNA (tRNA) molecules
contain a particularly large number of modified nucleosides. ATP consists of adenosine — composed of
an adenine ring and a ribose sugar — and three phosphate groups (triphosphate). Consequently, it is
closely related to the adenosine nucleotide, a monomer of RNA.

Assignment:
1. Create an aesthetically pleasing poster illustrating:
a. A molecular diagram of one specific type of carbohydrate
b. A molecular diagram of one specific type of lipid
c. A molecular diagram of a polypeptide between 3 and 6 amino acids in length
d. A molecular diagram of a nucleotide
2. Include a caption for each molecule that indicates:
a. The name of the molecule
b. Their common use by living organisms

Grading Rubric:
1. A aesthetically pleasing title for the poster that must be larger than any other printing on the
poster (4 points)
2. Correctly constructed illustrations showing a carbohydrate, lipid, polypeptide, and nucleotide
(18 points each, 72 points total)
3. Correctly identifying the name of the molecule (3 points each, 17 points total)
4. Correctly identified a common use by living organisms (3 points each, 17 points total)

Points Deducted:
1. Aesthetics:
a. Any smudges or extraneous marks will have a deduction of 5 points for each area or
mark that is smaller than 3 cm2
b. Unappealing symmetry or balance will result in a 10 point deduction
2. Misspelling or incorrect punctuation will have a deduction of 5 points each