Classes of Organic Molecules

CLASSES OF ORGANIC
MOLECULES
CLASSES OF ORGANIC
MOLECULES
What are organic molecules?
These are molecules that have their
basic skeleton made of carbons atoms,
hydrogen, oxygen and sometimes
nitrogen atoms. Generally organic
molecules in the body can be classified
into one of four groups: carbohydrates,
lipids, proteins and nucleic acid.
Carbohydrates
Carbohydrates are the most abundant
of the four main organic molecules.

They fill numerous roles in living things,
such as the storage and transport of
energy (starch, glycogen) and structural
components (cellulose in plants, chitin
in animals). Most carbohydrates taste
sweet, and the carbohydrates include
the substances known as sugars.
Cont..
The simplest sugars are known as
monosaccharides, a good example of

a monosaccharide is glucose.
a.Simple sugars/monosaccharides
- the basic building block
molecules of the carbohydrates
Cont
- all sugar, when in straight-chain
form, contain a C=O group.
Hydroxyl (OH) groups are attached
to all the carbons except those
with a double bonded oxygen.
a.1. glucose
a.2. galactose
1.3 fructose
Cont.
In addition to ordinary monosaccharides

composed only of carbon, oxygen and
hydrogen, there are a variety of
derivative monosaccharides containing
other elements.
Some have a phosphate group
attached to one of the carbons and
others an Amino group ( a nitrogen with
two hydrogen, NH2).
A.1 glucoamine
a.2 Glucose 6-phosphoric acid
Cont
Glucose is the major monosaccharide found

in the blood, when two monosaccharide are
linked together they form a disaccharides.
b. Disaccharides, or double sugars are
composed of two single sugars bonded
together through a reaction that involves a
removal of a molecule of water. This kind of
reaction is called condensation reaction or
a dehydration reaction.
a. Maltose/Malt sugar this compound is

synthesized by a condensation reaction
between two molecules of glucose.
2C6H12O6
C12H22O11 + H2O
b. Lactose/Milk sugar composed of glucose and
galactose.
Synthesized by condensation reactions,
dissacharides can be broken down to their
constituent simple sugars by reverse

process. This process or reaction is
called Hydrolysis, involves addition of
water molecule
C6H12O6 + H2O
2C6H12O6
c. Sucrose/table sugar it is synthesized by

condensation reaction between molecules
of glucose and a molecule of fructose.
C. Polyssacharide is a straight or
branched chain of hundreds or
thousands of sugar units of the same or
different kinds.
Most common are:
1) Starches
- are the principal carbohydrate storage
products of higher plants
- composed of many hundreds of
glucose units bonded together.
2) Glycogen the principal

carbohydrate storage product in animal
Sometimes called animal starch.
Glycogen is found in animal cells and
it serves as primary short term energy
storage in animal cells. It is made
primarily by the liver and the muscles.
3) Cellulose highly insoluble
unbranched polysaccharides common
in plant
-major supporting material
Reactions like those that form
polysaccharides are reactions in

which small molecules bond together
to form long chains are called
POLYMERIZATION REACTIONS.
The products formed are called
POLYMERS.
Lipids
Are composed of carbon, hydrogen and oxygen,
but they may also contain other elements,
particularly phosphorus and nitrogen.
Lipids are fat-soluble, naturally occurring
molecules; unlike carbohydrates lipids are

insoluble in water, but they do dissolve in
nonpolar solvent such as ether.
The main biological functions of lipids

include energy storage, acting as
structural components of
cell membranes, and participating as
important signaling molecules
Lipids can be divided into subclasses:

I) Fatty acid has a long unbranched
carbon with a - COOH at the end.
Each molecule of fat is composed of two a

different types of building-block
compounds.
-An alcohol called glycerol and fatty acids.
-Glycerol (also called glycerin) has a
backbone of three carbon atoms, each
carrying a carboxyl group (-OH group)
Fatty acids like all organic acids,
contain the acid group COOH (called

carboxyl group)
O
C
OH
The various fats differ in the specific
fatty acids or types of fatty acids of

which they are composed:
A) Saturated fats including butter
and lard tend to be solids at room
temperature.
Saturated means all the carbon
atoms in the fatty acid tails are joined
by single C-C bonds and as many
hydrogen atoms as possible are linked
to them.
2) Unsaturated fats or oils tend to be

liquid at room temperature. One or
more double bonds occur between
the carbon atoms in the fatty acid
tails.
Oils are liquid at room temperature

because the double bond create
kinks that disrupt packing between
tails.
B. Phospholipids
Contain phosphorus in the form of
phosphate
it has glycerol backbone
attached to the backbone are two fatty
acid tails, a phosphate group and a small
hydrophilic group
Main component of the cell membrane
Controls the movement of materials in
and out of the cell.
C. Waxes
- composed of fatty acids and certain
alcohol
- some wax secretion form coatings
that help protect, lubricate and
maintain the pliability of skin and hair.
2) Lipids with no fatty acids
- among the lipids that have no fatty
acid tails are the steroids
Cholesterol is a steroid which is a key
component of animal cell membranes

Used to synthesize vitamin D which
functions in the development of bones
and teeth.
Excess cholesterol also plays a role in
ATHEROSCLEROSIS a disorder in which
the lipids becomes deposited in the
walls of arteries. The deposits build up,
arteries narrow and blood flow may be
obstructed.
Many hormones, including sex

hormones are steroid. Hormones
help regulate the bodys growth,
development and reproduction, as
well as its everyday functioning.
Unfortunately, use of those steroids
can lead to pronounced
behavioural disorders, liver
damage and other abnormalities.
Proteins
Proteins are large organic compounds
made up of amino acids (amino acids are

organic molecules that are made of
carbon, nitrogen and hydrogen atoms).
These amino acids are arranged in a
linear chain and joined together by
peptide bonds between the carboxyl and
amino groups of adjacent amino acid
residues.
Example illustrating the

formation of a peptide bond
Cont
Peptide bonds are formed between
the amino and carboxyl group. These

bonds can be broken by hydrolysis to
yield individual amino acids. The
figure on the previous slide illustrates
the hydrolysis of a protein.
PROTEIN STRUCTURE
Proteins are characterized of three types of
structures namely: primary, secondary,
tertiary and quaternary structure.
Primary Protein Structure
The primary structure of a protein refers to
the number and sequence of amino acids
in the protein. The primary structure of a
protein is very important in the
identification of a protein.
Diagram showing the primary

structure of a protein
Cont..
Secondary Protein Structure
The secondary protein structure is
the specific geometric shape caused
by intramolecular and intermolecular
hydrogen bonding of amide groups.
The most common secondary
structures of proteins are the alpha
helices and beta sheet.
Diagram showing the

secondary structure of a
protein
Cont
Tertiary Protein Structure
The third type of structure found in
proteins is called tertiary protein
structure. The tertiary structure is the
final specific geometric shape that a
protein assumes. This final shape is
determined by a variety of bonding
interactions between the "side chains" on
the amino acids.
These bonding interactions may be

stronger than the hydrogen bonds
between amide groups holding the
helical structure. As a result, bonding
interactions between "side chains"
may cause a number of folds, bends,
and loops in the protein chain.
Different fragments of the same chain
may become bonded together.
The figure on the next slide, shows the
difference between primary, secondary
and tertiary protein structures:
Different protein structures
Quarternary Protein
Structure
The quaternary protein structure
involves the clustering of several

individual peptide or protein chains
into a final specific shape. A variety
of bonding interactions including
hydrogen bonding, salt bridges, and
disulfide bonds hold the various
chains into a particular geometry.
Figure showing quaternary

protein structure
Nucleic Acids
These organic molecules are responsible
for the storage, expression, and
transmission of genetic information. It is
the expression of genetic information
that determines whether a cell is a
muscle cell or a nerve cell. There are
basically two classes of nucleic acids,
deoxyribonucleic acid (DNA) and
ribonucleic acid (RNA).
Nucleic Acid are the only organic
compound capable of replicating

themselves
Involved in the storage and transmission
of energy and cellular information.
The structural block of nucleic acid is
the nucleotide which is comprised of a
phosphate group (PO4), a five carbon
sugar (ribose or deoxyribose) and a
nitrogen base, either a purine ( adenine
or guanine) or pyrimidine (cytosine,
thymine or uracil)

Classes of Organic Molecules

Uploaded by

Copyright:

Available Formats

Classes of Organic Molecules

Uploaded by

Document Information

Original Description:

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Classes of Organic Molecules

Uploaded by

Copyright:

Available Formats

CLASSES OF ORGANIC

of the four main organic molecules.

monosaccharides, a good example of

In addition to ordinary monosaccharides

Glucose is the major monosaccharide found

a. Maltose/Malt sugar this compound is

constituent simple sugars by reverse

c. Sucrose/table sugar it is synthesized by

2) Glycogen the principal

Reactions like those that form

polysaccharides are reactions in

Lipids are fat-soluble, naturally occurring

molecules; unlike carbohydrates lipids are

The main biological functions of lipids

Lipids can be divided into subclasses:

Each molecule of fat is composed of two a

Fatty acids like all organic acids,

contain the acid group COOH (called

The various fats differ in the specific

fatty acids or types of fatty acids of

2) Unsaturated fats or oils tend to be

Oils are liquid at room temperature

Cholesterol is a steroid which is a key

component of animal cell membranes

Many hormones, including sex

made up of amino acids (amino acids are

Example illustrating the

the amino and carboxyl group. These

Diagram showing the primary

Diagram showing the

These bonding interactions may be

Different protein structures

involves the clustering of several

Figure showing quaternary

Nucleic Acid are the only organic

compound capable of replicating

You might also like