Organic Molecules
L.E.Q. What are the four main biological molecules?
The Chemistry of Living Things
Organic compounds – contain Carbon
And Hydrogen
Inorganic compounds – do not
Carbon is an ideal Building Block
Carbon is able to bond to itself and
other elements to form large
molecules.
Organic molecules are usually large. How
are they made?
 Monomer – a small, repeating unit
(molecule)
 Polymer – many monomers bonded
together.
 Macromolecule.
 A large molecule
How do Monomers form Polymers?
 Dehydration Synthesis
 Dehydration means to take water out
 When monomers bond together they lose a water
molecule
The purple dots represent
Carbon atoms
https://www.youtube.com/watch?v=PYH63o10iTE time 4:14
Since many organic
molecules have the
elements oxygen and
hydrogen in them,
this isn’t hard to do.
The 4 Types of Biological (Organic)
Molecules
Carbohydrates
Lipids
Nucleic Acids
Proteins
Carbohydrates
 Structure (contain what elements?)
 C, H, and O
 They are found in a ratio of 1C : 2H : 1O
Monomer of Carbohydrates (or the Building Blocks)
 Monosaccharide
 Single sugars (one molecule)
 Examples are glucose and fructose (C6H12O6)
glucose
Found in plants and animals
Fruit sugar found in many plants
HONORS
Carbohydrates - Disaccharides
 Double Sugar
 Made of two monosaccharides
 Most common disaccharide is sucrose (glucose+fructose)
 Found in plant sap
 We use it to make table sugar
 Lactose is the sugar present in milk.
Carbohydrates- What is their Function?
Primary Energy Source
 Glucose is a simple sugar that our body uses
as its main source of fuel
Carbohydrates- What is their Function?
 Storage of Energy
 Carbohydrates can also be stored away for later use.
 Examples
 Starch
o Plants store food in the form of starch
Carbohydrates- What is their Function?
 Storage of Energy
 Another Example
Glycogen
o Humans store glycogen in their liver.
o This can be converted to energy when needed
Carbohydrates- What is their Function?
Structural
– serves as building material in plants and other organisms.
- many monosaccharide's bonded together – a polysaccharide
EXAMPLES
 Cellulose
 building material of plant
cell walls
 Chitin
 Forms cell walls in fungi
(mushrooms) and the
exoskeleton of arthropods
Lipids
There are many
Hydrocarbons
C-C-C-C-C-
Carbons with hydrogen
bonded to them
Structure
 They are not made up of monomers they are
simply one monomer
Lipids
 Many Lipids are NOT soluble in water.
 Meaning – they do not dissolve in water
They are non-polar
molecules.
• Remember water
is polar, so other
polar molecules
will dissolve in
water
Oil and water
don’t mix
Groups of Lipids – Fats
 Saturated Lipids: every carbon
atom contains the most # of
hydrogens that it can.
 Contained in animal products.
 Solid at room temp.
 Unsaturated Lipids:
there is at least 1 double
bond bet. carbon atoms.
 Plant oils.
 Liquid at room temp.
FYI – Trans Fats
Function of Fats

Energy reserves
 carbohydrates give short term energy storage
 (carbs can be turned into fats)
 Lipids give LONG term energy storage
Protective
cushion and
insulator
Source of energy in
hibernating animals
Lipids - Phospholipids
 Function as parts of cell membranes
 form the bilayer that make up cell membranes.
 Serves as a boundary between the cell and the
environment
 Are soluble in water
Lipids - Steroids
 Include Cholesterol and Sex Hormones
 Cholesterol is a component of cell membranes and helps
keep them fluid
 Sex hormones include testosterone and estrogen
Nucleic Acid –Structure
 Made up of Nucleotides
 These monomers are repeated many times
 Each Nucleotide consists of
 5-Carbon sugar
 Phosphate Group
 Nitrogen containing Base
Contains
C, H, N, O and
Phosphorus
Nucleic Acids- Function
Carries Genetic information
 Examples are DNA (deoxyribonucleic
acid) and RNA (ribonucleic acid)

Proteins
 Proteins are instrumental in almost everything
organisms do! (in Greek protein means “first place”)
 Also called polypeptides
Protein - Structure
 Monomers (Building Blocks)

Amino Acids
Consists of
C, H, O, and N
Many amino acids are folded into a
unique 3 dimensional shape.
Protein Structure
honors
a) Primary – the
sequence of the
amino acids
b) Secondary- the
forming of
hydrogen bonds
c) Tertiary – the
three dimensional
structure
d) Quaternary –
three dimensional
structure when the
protein has multiple
units
Protein - Functions
 Structural proteins – for support
 Making webs. Keratin is the protein of hair, horns and feathers
 Storage proteins
 Egg white is the amino acid source for the developing embryo
 Plants have storage proteins in their seeds
 Transport Proteins
 Hemoglobin, transports oxygen in the blood.
 Hormonal proteins
 Insulin helps regulate the concentration of sugar in the blood
 Defensive proteins
 Antibodies combat bacteria and viruses
 Enzymatic Proteins are probably the most important type of protein
 Enzymes regulate metabolism by speeding up chemical reactions.
Protein -Function
 ENZYMES
 proteins that act as catalysts to speed up chemical
reactions
 Catalyst – a substance that enables a chemical reaction to
proceed at a usually faster rate.
 The enzyme is not consumed in the reaction and can be
used over and over.
Chemical Reactions
If enzymes speed up chemical reactions, lets review
what a chemical reaction is.
 Chemical Reaction - a process that changes,
or transforms, one set of chemicals into another.
 Chemical Reactions are going on in your body all the time.
Parts of a Chemical Reaction
Reactants
The elements or compounds that enter into a chemical
reaction
C6H12O6 + 6O2  6CO2 + 6H2O + useable energy
Glucose and Oxygen are the reactants
Parts of a Chemical Reaction
Products
The elements or compounds produced by a chemical
reaction.
The arrow stands for produce
C6H12O6 + 6O2  6CO2 + 6H2O + useable energy
Carbon dioxide, water, and energy are the products
Types of Reactions
Physical Reaction
A physical reaction does not
produce a new substance.
The substance just changes its
state, like solid to liquid. May
change its size or shape
Example: Ice melting
Chemical Reaction
 A chemical reaction produces
a new substance. Something
that wasn’t there before.
 Clues a chemical reaction
took place.
 Heat, light, colors, gas, and
smells can be produced.
 Examples:
 Cooking, burning
Protein - Enzymes
How Enzymes Function
 Substrate – the “reactants” . These bind to the
enzyme
 Active Site – where the “reactants” bind to the enzyme
 Products – what is formed during the reaction
There are many different enzymes, but each one will only fit one substrate. Like a
lock and key.
The enzyme speeds up the reaction and forms the Products.
Protein – Enzyme Functions
 Enzymes require specific conditions to function normally
 Factors that affect enzyme function
 Heat
 pH
 If it gets too hot, or the pH changes, then the structure
of the enzyme is affected and the reaction can’t take
place.
 The enzyme is Denatured
Examples of Enzymes
 Enzyme names usually end in ase
 Lactase is an enzyme found in the intestine and helps break down lactose (a
milk sugar) into other simple sugars.
 What happens if you lack this enzyme? Lactose will travel to the large intestine and
produce gas (which can be very uncomfortable)
 Catalase is an enzyme found in red blood cells. It breaks down hydrogen peroxide into
water and oxygen. Too much hydrogen peroxide is toxic and people who cannot break it
down can develop infections. It can also lead to cancer.
Monomers of Organic Molecules
Organic Molecule
Monomer
Carbohydrate
Monosaccharide
Nucleic Acid
Nucleotide
Protein
Amino acid