Four Types of
Organic Molecules
Made by cells
Contains carbon
Importance of Carbon
Although cells are 70-95% water, the rest
of composed mainly of carbon
compounds.
Proteins, carbohydrates, DNA, and other
molecules are compounds of carbon
bonded to other elements.
Carbon often bonds to H, O, N, S, and P in
organic compounds.
Properties of Carbon
Has four valence electrons; can form
covalent bonds with four other atoms
(tetravalence)
Carbon bonded to four atoms forms a
tetrahedron-shaped molecule.
Carbon can form single, double, or triple
bonds with other atoms.
Carbon chains form the backbone of most
organic molecules.
Chains can be straight, branched, or
arranged in closed rings.
Hydrocarbons contain carbon and
hydrogen only, and are hydrophobic. H—C
and C—C bonds are nonpolar.
Hydrocarbons make up fossil fuels, and
parts of cellular organic molecules such as
fats and phospholipids.
1. Carbohydrates- used as fuel and
building material
2. Lipids-energy storage
3. Proteins-structure, movement, enzymes
4. Nucleic acids-store and transmit
hereditary information.
They are macromolecules because of their
large size.
The largest
Macromolecules
are called polymers
Created by linking
smaller subunits
called monomers.
Dehydration
Monomers are linked together to form
polymers through dehydration reactions,
which remove water
Monomers are linked together by covalent
bonds
Short polymer
Dehydration
reaction
Longer polymer
Unlinked
monomer
Hydrolysis
Polymers are broken apart by hydrolysis,
the addition of water
Breaks covalent bonds between
monomers
Hydrolysis
Review Q:
Hydrolysis is involved in which of the
following?
A) Formation of starch
B) Hydrogen bond formation between amino
acids
C) Peptide bonds in proteins
D) The hydrophobic interactions in lipids
E) The digestion of maltose to glucose
Hydrocarbons
Compounds made of
only carbon and
hydrogen.
Found in a variety
of structures.
1. Length
2. Branching
3. Double bonds
4. Rings
Isomer – same molecular
formula, different structure.
Length.
Carbon skeletons vary in length.
Branching.
Skeletons may be unbranched or branched.
Skeletons may have double bonds,
which can vary in location.
Rings.
Skeletons may be arranged in rings.
functional group determine the
properties of organic compounds
Compounds containing functional groups
are hydrophilic (water-loving)
6 Functional groups
–
–
–
–
–
–
Hydroxyl group —a hydrogen bonded to an
oxygen
Carbonyl group — a carbon linked by a
double bond to an oxygen atom
Carboxyl group —a carbon double-bonded
to both an oxygen and a hydroxyl group
Amino group —a nitrogen bonded to two
hydrogen atoms and the carbon skeleton
Phosphate group —a phosphorus atom
bonded to four oxygen atoms
Methyl group – a carbon bonded to three
hydrogens.
An example of similar compounds that differ only
in functional groups is sex hormones.
Estradiol
Female lion
Testosterone
Male lion
1. Carbohydrates – all carbs are in a
1:2:1 ratio of C:H:O
monosaccharides - simple ring sugars

glucose and fructose (and galactose)
C6H12O6
* A 6-carbon sugar
* The sugar in our blood
* A 6-carbon sugar
* the sugar that sweetens fruit
Diabetes
Disease characterized by high levels of
blood glucose resulting from defects in
insulin production
Monitored with blood glucose device.
disaccharides - two monosaccharides
Glucose + fructose = Sucrose (table sugar)
Glucose + galactose = Lactose (milk sugar)
Glucose + glucose = Maltose (malt sugar)
Remember dehydration reaction!
(Makes a glycosidic linkage – O binds 2
monosaccharides)
What kind of bond would this linkage be?
Glucose
Glucose
Maltose
Lactose intolerant
If the enzyme lactase is not present, the body is unable to
break down lactose. Allowing it to reach the large intestines.
Normally, sugars do not reach the large intestine. This is what
causes a stomach ache!
What is high-fructose corn syrup?
polysaccharides - repeating units of
monosaccharides, these are used in energy
storage and as structural components.
Energy

starch (plants produce for a storage molecule.)

cellulose (plants produce for cell wall construction.)
indigestible because we lack enzymes to break it down.


Structural
glycogen (storage molecule in muscle and liver cells.)
chitin (used by insects and crustaceans to build an
exoskeleton.)
Starch, Cellulose & Glycogen
All the sugars
are oriented in
the same
direction
Branched or
"forked"
Every other
sugar molecule
is "upside-down
Review Q:
Polymers of carbohydrates are all
synthesized from monomers by
A) the joining of disaccharides.
B) hydrolysis.
C) dehydration synthesis.
D) ionic bonding between monomers
E) cohesion.
2. Protein - Proteins make up 50% of
cellular dry weight.
Made of a long chain of amino acids
linked by dehydration reaction
Amino acids (building blocks)
Have an amino group and a carboxyl group
Also a chemical group symbolized by R
Amino
group
Carboxyl
group
–
Dehydration reaction links the carboxyl group
of one amino acid to the amino group of the
next amino acid
– The covalent linkage resulting is called a peptide
bond
Carboxyl
group
Amino
group
Dehydration
reaction
Peptide
bond
Dipeptide
Amino acid
Amino acid
Peptide bonds
Peptide bonds are covalent bonds formed by
a condensation reaction that links the
carboxyl group of one amino acid to the
amino group of another.
Has polarity with an amino group one end (Nterminus) and a carboxyl group on the other
(C-terminus).
Has a backbone of repeating N-C-C-N-C-C
Polypeptide chains range in length from a few
monomers to more than a thousand, and a
unique linear sequence of amino acids.
The R group determines if the amino acid
is hydrophobic or hydrophilic.
Hydrophobic
Leucine (Leu)
Hydrophilic
Serine (Ser)
Aspartic acid (Asp)
A protein’s specific shape
determines its function
A polypeptide chain contains hundreds or
thousands of amino acids linked by
peptide bonds
–
–
The amino acid sequence causes the
polypeptide to assume a particular shape
The shape of a protein determines its specific
function
A.A. sequence = shape = function!
Proteins function as…
Structural proteins (support)


keratin for hair and nails
collagen for bones, ligaments, tendons, skin
Proteins function as…
Contractile

Found in muscle cells, enables them to move.
Proteins function as…
Enzymatic proteins promotes chemical
conversion, as well as speeds up
reactions.
Example: Amylase is an enzyme in saliva
that breaks starch into glucose monomers.
Saliva
Saliva Identification - Amylase
Proteins function as…
Transport across cell membranes

Hemoglobin
Defense from infection

Antibodies
Signal


hormones
Insulin
Insulin is a hormone
that helps your body
use glucose.
Proteins function as…
Storage

Source of food for developing embryos.
Albumin (egg whites)

experiences heat coagulation (denaturation)
Protein in seeds.
Receptor

Built in cell membrane. Transmits signals to
the inside of the cell.
Protein
structure is
key to their
ability to
function.
**A protein can be denatured,
heat, salinity, pH can cause it to
lose its shape, and its
functionality..
A protein can have four levels of
structure
–
Primary structure
–
Secondary structure
–
Tertiary structure
–
Quaternary structure
structure
The primary structure of a protein is its
unique amino acid sequence
Protein secondary structure results from
coiling or folding of the polypeptide held by
hydrogen bonds.
–
–
Coiling = alpha helix structure
Folding = pleated sheet structure
structure
The overall three-dimensional shape of a
protein is called its tertiary structure
–
results from interactions between the R
groups of the amino acids
Two or more polypeptide chains (subunits)
associate providing quaternary structure
Four Levels of Protein Structure
Primary structure
Amino acids
Hydrogen
bond
Secondary structure
Alpha helix
Tertiary structure
Quaternary structure
Pleated sheet
Polypeptide
(single subunit
of transthyretin)
Transthyretin, with
four identical
polypeptide subunits
Linus Pauling
After winning a Nobel Prize in
chemistry, Pauling spent
considerable time studying
biological molecules
–
–
He discovered an oxygen attachment to
hemoglobin as well as the cause of sickle-cell
disease
Pauling also discovered the alpha helix and
pleated sheet of proteins
Review Q:
The linkage between the monomers of
proteins are identified as
A) Peptide bonds
B) Glycosidic linkages
C) Ionic bonds
D) Covalent bonds
E) Ester linkages
Review Q:
Which two functional groups are always
found in amino acids?
A) Amine and sulfhydryl
B) Carbonyl and carboxyl
C) Carboxyl and amine
D) Alcohol and aldehyde
E) Ketone and amine
3. Nucleic Acids
Stores information
Two types:
DNA
(deoxyribonucleic acid)

RNA
(ribonucleic acid)

Nitrogenous
base
(adenine)
Phosphate
group
Sugar
Nucleotides are the
building blocks of Nucleic
acids.
Have 3 parts:
* 5 carbon sugar   The sugar is either:
1. deoxyribose
* phosphate group
2. ribose
* nitrogenous group
Dehydration synthesis
Polynucleotides are formed from its
monomers bonding together through
dehydration synthesis.


The phosphate group of one nucleotide bonds
to the sugar of the next.
The result is a repeating sugar phosphate
backbone.
4 base pairs
DNA nitrogenous bases are




adenine (A)
thymine (T)
cytosine (C)
guanine (G)
RNA also has A, C, and G, but instead of
T, it has uracil (U)
DNA molecules have thousands or even
millions of base pairs.
Double helix
Two DNA strands wrap around each other
to form a double helix
–
–
–
The two strands are connected by a
hydrogen bond between the base pairs.
A pairs with T
C pairs with G
RNA is usually a single strand
Genes (consist of DNA) codes for the
sequence in which the amino acids are
arranged (primary structure of proteins).
Genes do not use DNA to code directly.
Genes use an intermediary (RNA).
The DNA is transcribed into RNA, which is
then translated into the amino acid
sequence.
Flow of information:
DNA  RNA  Proteins
Review Q:
Which list of components characterizes
RNA?
A) A phosphate group, deoxyribose, and
uracil
B) A phosphate group, ribose, and uracil
C) A phosphate group, ribose and thymine
D) A phosphate group, deoxyribose, and
adenine
4. Lipids
Hydrophobic – Will not mix with water
• Important to energy storage!
• Often called triglycerides
Fats are lipids made from
1 glycerol and 3 fatty acids
linked by a dehydration
reaction.
Glycerol
Fatty acid
Kink
Saturated
Saturated – health risks


Atherosclerosis
Heart Disease
Types of Lipids:
Phospholipids - form cell membranes
Hydrophilic
head
Hydrophobic
tails
The polar heads are
towards the water,
the nonpolar tails are
on the inside of the
cell.
Phospholipids
Where fats have a third fatty acid linked to
glycerol, phospholipids have a negatively
charged phosphate group.
This makes the “head” of the phospholipid
hydrophilic; the hydrocarbon “tails” are
hydrophobic.
Phospholipids are the major components of cell
membranes. In a cell membrane, the
hydrophobic tails are orientated inward, while
the hydrophilic head face outward.
 Steroids cell messengers
 examples: testosterone, estrogen (estradiol)
 Waxes protection & waterproofing
An example of similar compounds that differ only
in functional groups is sex hormones.
Estradiol
Female lion
Testosterone
Male lion
Anabolic steroids pose health risks
Anabolic steroids are synthetic variants
of testosterone that can cause a buildup of
muscle and bone mass.
Cause liver damage,
cancer & other serious
side effects…
Function of lipids
Energy storage- fats store twice as many
calories/gram as carbs.
Protection of vital organs and insulation in
humans and other mammals.
Phospholipids make up cell membranes.
Steroids are often in cell membranes
(cholesterol) and make up some
hormones (estrogen and testosterone)
Review Q:
Which macromolecule is the main
component of cell membranes?
A) Glucose
B) Steroids
C) Carbohydrates
D) Phospholipids
E) DNA
Review Q:
Which of the following macromolecules below
could be structural parts of the cell, enzymes,
or involved in cell movement or
communication?
A) Nucleic acids
B) Proteins
C) Lipids
D) Carbohydrates
E) Minerals
You should now be able to
1.
2.
3.
4.
5.
6.
7.
Discuss the importance of carbon to life’s molecular
diversity
Describe the chemical groups that are important to life
Explain how a cell can make a variety of large
molecules from a small set of molecules
Define monosaccharides, disaccharides, and
polysaccharides and explain their functions
Define lipids, phospholipids, and steroids and explain
their functions
Describe the chemical structure of proteins and their
importance to cells
Describe the chemical structure of nucleic acids and
how they relate to inheritance