2.3: Carbon Based
Molecules
Situation:
• You are tasked with making Chicken Parm and ziti
for you entire family (aunts, uncles, cousins, etc).
There are 92 different ingredients you have access
to in the kitchen. Do you use all of them? Why or
why not?
Of the 92 naturally existing elements
on the Earth, only 25 play a role in
the chemical processes of life. Of
these 25, four elements constitute
more than 98 percent of all biological
matter: carbon (C), oxygen (O),
hydrogen (H), and nitrogen (N)
Refresher:
• What do we remember about CARBON?
• What makes it special?
• Nickname?
• Where do we find it?
Carbon – Building block of life
• Found in all living things!
• “building block” – it can bond with 4 other atoms,
including other carbons!
• Commonly found in all 3 forms on earth
• Solid, liquid, or gas
Carbon continued:
• Each carbon has 4 valence electrons
• It can form 4 strong covalent bonds with other molecules
• Can bond with other carbons
• Can form 3 different shapes when bonded together:
Macromolecules
• Formed by a process known as
polymerization
• Small units called monomers join together
to form larger polymers
• 4 major macromolecules/polymers in our
bodies:
1. Carbohydrates
2. Proteins
3. Lipids
4. Nucleic Acids
Macromolecules are the “ingredients of life”!
• All organisms either need to synthesize or
ingest all of the macromolecules in order
to survive
Also….
Biological molecule = Carbon-based molecule = Organic molecule
Same thing! Just different names
Carbohydrates
• Energy-rich compounds made of Carbon,
Hydrogen, and Oxygen that are often found in a
ring shape
• The ratio of Carbon:Hydrogen:Oxygen is usually
1:2:1
• One of the most important carbohydrates in our
body is the monomer glucose
Carbs continued…
• Carbohydrate polymers are made from single sugar
monomers called monosaccharides
• Examples of monosaccharides (aka simple sugars):
• Glucose, galactose (found in milk), and fructose (found
in fruits)
• When 3 or more monosaccharides are combined a
polymer called a polysaccharide forms
Example of a disaccharide:
+
Glucose
=
Fructose
Table sugar (sucrose)
Example of a polysaccharide (storage):
=
Cellulose
Important Carbohydrates:
• Living things break down simple
sugars (glucose) as their main source
of SHORT TERM energy
In animals:
Glycogen- energy stored in liver and
skeletal muscle
• Stored energy
• In between meals and during physical
In Plants: Cellulose is used to give the cell wall structure
activity, glycogen is broken down into
**Think of stringy and tough celery
glucose
In other organisms: Chitin is a polysaccharide that makes up the hard
outer shell (aka exoskeleton) of shrimp, lobsters, some insects, and cell
wall of some fungi
Lipids
Fats
Waxes
Oils
Steroids
Lipids
• Lipids are commonly referred to as “fats”
• Fats and oils are 2 types of lipids that store large
amounts of *****LONG TERM ***** energy
• Fats are usually solid at room temperature
• Oils are usually liquid
Lipids are usually
NOT soluble in water!
Lipids
• Triglycerides are formed when a glycerol molecule combines with
compounds called fatty acids (that are in chain form).
• If each carbon atom in a lipid’s fatty acid chain is joined to another carbon atom by a
single bond, the lipid is said to be saturated.
Saturated lipids:
Single bond = Saturated = Solid
These foods are generally bad for you and cause high
cholesterol.
Examples: butter, lard, fatty beef, processed foods
Lipids
• If there is at least one carbon-carbon double bond in a fatty
acid, it is unsaturated.
• Lipids whose fatty acids contain more than one double
bond are polyunsaturated.
• Lipids that contain
unsaturated fatty acids tend to
be liquid at room temperature
(like oils).
Monomer: Triglyceride
Other examples of lipids and
functions:
Waxes
Used to coat and protect things in nature
EX: Ear wax, bee honeycombs, plants
Plants use waxes on their surface to prevent water from
evaporating
Steroids
A ring shaped hormone found in animals
Affects many functions in the body by sending chemical
messages
Lipids in cells:
All cell membranes are made of a lipid called a phospholipid
A phospholipid has a glycerol head and 2 fatty acid tails
The lipids of a cell membrane prevent the contents of the cell from being
dissolved in water
(remember, lipids are usually NOT soluble in water)
Proteins
Proteins
• Proteins are macromolecules that contain nitrogen,
carbon, hydrogen, and oxygen.
• Proteins are polymers of monomers called amino acids
• There are 20 kinds of amino acids
• All a.a. end in “-ine”
Quick Math…
• If there are 20 different amino acids and we put
together different combinations of them in groups
of 20, how many possibilities could we reach? (this
is not realistic as some proteins have more or less
amino acids than 20)
20 x 19 x 18 x 17 x 16………..
20!
2.432902e+18
Proteins
• Proteins have the most different forms of all the
macromolecules
• Your body makes 12 amino acids – you need to
ingest the others from foods like:
• Meat
• Beans
• Nuts
Proteins
• Different amino acids are strung together into chains according to the
letter code written in nucleic acids (DNA and RNA).
• The three letter codes in the RNA correspond to a
particular amino acid.
Proteins
•More than 2 amino acids strung together make a
polypeptide. (a protein polymer)
Amino
Acids
Protein Molecule
Proteins
• The bonds between amino acids are called peptide
bonds
• Peptide bonds are covalent bonds
Proteins - functions
• Some proteins control the rate of reactions and regulate cell
processes. (Enzymes)
• Some proteins are used to
form bones and muscles.
• Other proteins transport
substances into or out of cells
or help to fight disease.
Nucleic Acids
• Nucleic acids are macromolecules containing hydrogen,
oxygen, nitrogen, carbon, and phosphorus.
• Nucleic acids (DNA and RNA) are polymers assembled
from individual monomers
known as nucleotides.
Nucleotides
Nucleic Acids
•Nucleotides consist of three parts:
• a 5-carbon sugar
• a phosphate group
• a nitrogenous base
• Individual nucleotides can be joined by covalent bonds to
form a polynucleotide, or nucleic acid.
Nucleic Acids
•There are two kinds of nucleic acids, ribonucleic acid (RNA) and
deoxyribonucleic acid (DNA).
• RNA has the sugar
ribose.
• DNA has the sugar
•deoxyribose (one less oxygen)
Function of Nucleic Acids
• Nucleic Acids, like DNA,
stores genetic information
• They have the information
for our traits and are
passed down from parent
to offspring
• RNA has the information
for the cell to build
proteins