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Organic Molecules
Carbon can form 4 covalent bonds because it has 4 electrons
in its outer shell.
It can form the following number of bonds. Notice that in each
case below, there are a total of four bonds.

4 single bonds

two double bonds

one double bond and two single bonds

one triple and one single bond
Acetylene
Ethylene
Long chains of carbon atoms are common. The chains may be
branched or form rings.
Organic Molecules
Some molecules are hydrophobic (means "water fearing"). They
do not dissolve in water.
Nonpolar molecules and
functional groups are
hydrophobic.
Polar and ionic molecules and
functional groups are
hydrophilic.
Some molecules are hydrophilic (means "water loving"). They
dissolve in water.
Portions of large molecules may be hydrophobic and other
portions of the same molecule may be hydrophilic.
(Amphipathic)
Isomers
Different molecules that are composed of the same number and
kinds of atoms are called isomers. Glucose and fructose (shown
below) are both C6H12O6 but the atoms are arranged differently
in each molecule.
Same molecular formula: C6H12O6
Different structural formula
Which more useful?
Structural isomers differ in their overall construction as shown
above for glucose, galactose and fructose.
Functional Groups
Functional Groups - Groups of atoms attached to carbon skeletons that
behave/react in known ways.
Methyl
Lipids
Building and Breaking Polymers
https://www.youtube.com/watch?v=b7TdWLNhMtM
Polymers like polysaccharides, proteins and nucleic acids are
made from different monomers, but they are all built and broken
in the same way.
Monomer – 1 unit
HO-
-OH
Dimer – 2 units
HO-
-O -
Polymer – 3+ units
HO-
-O-
-OH
-O-
-O-
-OH
Dehydration Synthesis Reaction
Dehydration synthesis is a chemical reaction that takes smaller,
simpler molecules and combines them to form larger, more
complex molecules with the removal of one WATER molecule.
Dehydration = taking water out
Synthesis = putting together
Is a Dehydration Synthesis Reaction happening below?
Hydrolysis
The opposite reaction of dehydration synthesis is called
hydrolysis. This involves adding water to break apart large
molecules into smaller ones.
hydro = water.......lysis = breaking apart
Review Dehydration Synthesis and Hydrolysis
Macromolecules
A. Carbohydrates
Main function - provide energy for living things; also use carbon
skeletons to make other organic molecules
Elements: Carbon, Hydrogen and Oxygen
Simple sugars – Single sugar monomers and disaccharides
Complex sugars – Many sugar monomers bonded together
Monosaccharides (mono = single, saccharide = sugar)
Single sugar monomer
Most small sugars end in –ose
Most have the ratio: CH2O
Carbo (C) Hydrate (H2O)
 Glucose: C6H12O6
 Fructose: C6H12O6
 Galactose: C6H12O6
The structural differences between isomers give them their
unique properties.
 Fructose sweeter than glucose
Some sugars have 3 to 7 carbon atoms
Disaccharides (Di = 2)
2 sugar monomers bonded together
Made by what type of reaction? Dehydration Synthesis Reaction
How many water molecules were released?
Examples:
Maltose – Glucose + Glucose – Malt sugar
1
Sucrose – Glucose + Fructose – Plant sugar
Lactose – Glucose + Galactose – Milk sugar
Polysaccharides (Poly = many)
3 or more sugar monomers bonded together
Made by what type of reaction? Dehydration Synthesis Reaction
Starch
Structure: Looping chain of glucose monomers
 Branch or unbranched
Function: Plant sugar storage
 How is the sugar released? Hydrolysis
Foods: Potatoes and grains (wheat, corn and rice)
Glycogen
Structure: Highly branching chains of glucose monomers
Function: Animal sugar storage
 How is the sugar released? Hydrolysis
Food: Liver and muscle cells
Cellulose
Structure: Unbranched rod of glucose monomers
 Hydrogen bonds hold rods together
Function: structural compounds (support and protection)
Food: Fruits, vegetables, grains
 How is the sugar released?
o We can’t hydrolyze these polysaccharides
Organic Molecules – Crash Course http://www.youtube.com/watch?v=H8WJ2KENlK0
Introduction and Carbohydrates - Start – 7:07
Lipids - 7:07 – 10:45
Proteins - 10:45 - End
B. Lipids
Very Diverse – All hydrophobic = water fearing
 Fats/Oils
o Main functions: Energy Storage, cushion organs,
insulate
o Building blocks: Glycerol and 3 Fatty Acids
 Triglyceride
Elements: Carbon, Hydrogen and Oxygen
How many
water molecules
produced?
3
Saturated fats:
 Carbon chains hold the maximum number of hydrogen
atoms. NO carbon = carbon double bonds
 Solid at room temperature
 Animal fats
 Not healthy
Unsaturated fats:
 Carbon chains don’t hold the maximum number of
hydrogen atoms. Carbon = Carbon double bonds (C=C)
 Liquid (liquid-like) at room temperature
 Fish, plant fat
 More healthy
Hydrogenated – Hydrogen atoms have been added to molecules
to make them saturated.
 “Trans” fats are
linked to heart
disease.
 Phospholipids
o Main function: Structural component of the plasma
membrane
o Building blocks: Glycerol, 2 Fatty Acids and
Phosphate group (+ Choline)
 Waxes
o Main function: Retain water
 Fruits and insects
o Building Blocks: Alcohol + Fatty Acid
 Steroids
o Main functions: Hormones, cell membrane
components
 Cholesterol
 Sex hormones (testosterone and estrogen)
o Structure: 4 fused carbon rings ( 3, 6-sided and
1, 5-sided)
Anabolic Steroids – synthetic variants of the male hormone
testosterone.
 Mimic effects: muscle buildup and bone mass
 Side effects – “steRoid rage”, depression, liver damage,
cancer, high blood pressure, shrunken testicles, reduced sex
drive, infertility and breast enlargement. Women –
menstrual cycle disruption and masculine characteristics.
Teens – stops bone growth, stunts growth
C. Proteins
Main function: necessary for growth and repair of tissues, found
in cell membranes, enzymes, immune system,
signals, communication and other functions.
 Protein structure determines its function
Elements: Carbon, Hydrogen, Oxygen, Nitrogen and Sulfur
(some)
Monomer Building Block: Amino Acids (20)
 Type, number and order make each protein different
o Like letters in the English language
Amino Acids
 Each amino acid has 4 parts around a central carbon atom:
R-Group or
Side Group
R-Group or Side group – A variable part of an amino acid
o Could be a Hydrogen atom
o Could be a collection of atoms
 Determines the specific properties of each amino acid
o Hydrophobic or Hydrophilic
Dipeptides and Polypeptides
The carboxyl group of one amino acid and the amino group of
the next amino acid can join together by dehydration synthesis
to form a peptide bond.
 Additional amino acids added = Polypeptide
Peptide Bond
A protein’s shape determines its function
 If you change the shape, you change (possibly lose)
function.
o This could lead to a protein that
doesn’t function properly and
the death of the organism.
Protein Structure
Primary Structure (1o) – unique sequence of the amino acids.
Second Structure (2o) – Hydrogen bonding causes the primary
structure to fold onto itself
 Alpha helix – spiral
 Pleated sheet – folds
Tertiary Structure (3o) – the protein takes on 3-D shape
because of the hydrophobic and hydrophilic R-groups.
Quaternary Structure (4o) – 2 or more tertiary structures
bonded together.
 Collagen – fibrous protein
 Hemoglobin
Denaturation – unraveling the specific shape of a polypeptide
and changing its function
 Break the hydrogen bonds in the Secondary Structure
o pH, high temperatures, salt concentration
D. Nucleic Acids (DNA/RNA)
Observations/Similarities:Differences
Nucleic Acids
Main function: Information storage
 DNA – Long-term all genes
 RNA – Short-term 1 gene
 Gene – a specific portion of a DNA molecule that
codes for the production of a specific amino acid
sequence (protein).
DNA
RNA
Primary sequence of a protein
Elements: Carbon, Hydrogen, Oxygen, Nitrogen and
Phosphorous
Monomer Building Block: Nucleotide
Nucleotide – Made of 3 subparts
A. Five–Carbon sugar
a. Deoxyribose for DNA
b. Ribose for RNA
B. Phosphate Group
C. Nitrogenous Base
a. Adenine (A) – DNA and RNA
b. Guanine (G) – DNA and RNA
c. Cytosine (C) – DNA and RNA
d. Thymine (T) – DNA
e. Uracil (U) –
Purines
Pyrimidines
RNA
Polynucleotides are formed by Dehydration Synthesis Reactions
 The phosphate group of one nucleotide bonds to the sugar
of the next monomer to form a sugar-phosphate backbone.
RNA usually has a single sugar-phosphate backbone.
DNA is a double helix – two polynucleotide strands wrapped
around each other.
 Backbone on the outside
 Nitrogenous bases protrude inward and pair together
oA T
oG
C
 What do the lines represent?
Hydrogen Bonds
http://www.goldiesroom.org/Note%20Packets/04%20Biochemis
try/00%20Biochemistry--WHOLE.htm