The Chemistry of Life
• Lab Biology – Chapter 2
• Honors Biology – Chapter 3
Organic Chemistry
• All living things are mostly composed of
4 elements: H, O, N, C “honk”
• Compounds are broken down into 2
general categories:
• Inorganic Compounds:
– Do not contain carbon
• Organic compounds
– Contain significant amounts of carbon.
– Often found with common "functional
groups"
Carbon: The “Swiss Army Knife” of Chemistry.
• Carbon is essential to life
for several reasons:
– It can form strong stable
(usually non-polar) covalent
bonds
– It can form up to 4
chemical bonds
– It can form multiple bonds
Organic Compounds
• Organic Compounds often form Polymers
• Long chains of smaller molecules (not
atoms) called monomers, bind to form huge
Macromolecules
• 4 Types: Carbohydrates, Lipids, Proteins &
Nucleic acids
Why do people eat a bowl of
pasta before a competition???
Carbohydrates
• Includes: Sugars, starches, cellulose
& glycogen
• Made of Carbon ( C ), Hydrogen ( H ),
and Oxygen (O )
• Following ratio of elements CnH2nOn
• Sugars: Provide immediate energy
for cells
• Simple sugars include Glucose &
Fructose since these are made of
only 1 Carbohydrate molecule they
are known as Monosaccharides
Glucose: A Monosaccharide
Dehydration Synthesis
• Monosaccharides can be linked together through the process of
Dehydration Synthesis
– Water is removed from 2 monocaccharides - resulting in a covalent
bond between the 2 molecules
• Sucrose (table sugar) is made of 2 sugars linked together and
these are called Disaccharides
• Require some digestion to be used by cells
Hydrolysis
•
•
Dehydration synthesis is a reversible process Called Hydrolysis.
A water molecule is inserted where the monomers join. Breaking
their bonds.
Dehydration Synthesis Simplified
Hydrolysis Simplified
Polysaccharides
• Starches are many monosaccharides linked
together in a single chain. These are called
Polysaccharides.
– Plants use Starch for energy storage e.g. Potatoes
– Two types of starches
• Amylose - Long strait unbranched chains
• Pectins - many linked short Amylose chains
Starch
Cellulose
•
•
•
Cellulose is made of long polysaccharide chains
Plants use this for structure (e.g. Wood) - not very digestible
Due to the reverse orientation of the monosaccharide subunits,
digestive enzymes cannot hydrolyze the bonds between them
Cellulose
Glycogen
• Glycogen is a moderately branched polysaccharide
• Animals use this for short-term energy storage.
• Mostly stored in the human liver until converted to
fat
Glycogen
What makes McDonald’s fries taste
SOOOO good?
• ?
Lipids
•
•
•
•
•
•
•
Lipids are
macromolecules
including Fats,
Waxes and Oils.
Primary function is
energy storage.
Energy is stored in
C-H bonds.
More efficient in
storing energy
Lipids are made of 2
parts
Glycerol - an alcohol
- Serves as
backbone of the
molecule
3 Fatty acids - Long
hydrocarbon chains
Dehydration Synthesis of a Lipid
Hydrolysis of a Lipid
Types of fats
• Saturated fats have long chains with no double-bonds
• Unsaturated fats have double bonds
• Polyunsaturated fats have many double bonds
– Each time a double bond is encountered, the molecule "Bends"
slightly, resulting in a lower density of the lipid. This makes the
molecule more likely to remain liquid at room or body
temperatures. And thus, less likely to clog cardiac arteries.
Other Lipids
• 4 Other types of biologically important Lipids
– Phospholipids - Important for membrane structure
– Steroids - eg. Cholesterol & testosterone. Provide
membrane support / serve as hormones
– Terpenes - serve as important components of pigments
– Prostaglandins - appear to act like localized hormones to
induce cellular/tissue responses
What do you think is happening to
the proteins within these eggs????
Proteins
• Proteins are made of Amino Acids
• There are 20 different amino acids. Each having a similar
general structure - Differ only in their “R” groups
Peptide Bonds
• Amino acids form proteins via dehydration synthesis forming
peptide bonds
• Two amino acids linked together are called dipeptides
• More than 2 linked together are called polypeptides polypeptides can be thousands of amino acids long
Dehydration
synthesis
of a protein
Hydrolysis of a Protein
Protein Structure
• Protein types include globular
proteins which are usually enzymes
and Fiberous proteins which usually
serve for structure (eg. Hair)
• Proteins Exhibit 4 “levels of
structure.
Primary Structure
• Primary Structure of
a protein is it’s
sequence of amino
acids
• Primary Structure
dictates all further
levels of protein
structure
Secondary Structure
• The Sequence (primary
structure) causes parts of a
protein molecule to fold into
sheets or bend into helix
shapes - this is a protein’s
Secondary Structure.
Tertiary Structure
• The protein then can
compact and twist on
itself to form a mass
called it’s Tertiary
Structure
Quaternary Structure
•
•
•
Several Proteins then
can can combine and
form a protein’s
Quaternary Structure
Various conformations
are usually caused by
the formation of
hydrogen or disulfide
bonds.
PH, changes or heat can
disrupt these bonds,
permanently denaturing
the protein.
Nucleic Acids
•
•
•
•
Two types of Nucleic
acids
DNA
(Deoxyribonucleic
Acid)
RNA (Ribonucleic
acid)
DNA is Formed of in
a "Double Helix" like a spiral
staircase.
Nucleotides
•
•
•
DNA is formed from
Nucleotides
These are made of 3
components
– A 5-Carbon Sugar
– A Nitrogenous base
– A Phosphate group
Nucleotides form a backbone
through linkages from the OH
group of the 3rd carbon to a
phosphate group of the
adjoining nucleotide. These
are called Phosphodiester
bonds
Types of Nucleotides
•
•
•
•
•
For DNA There are 4 different Nucleotides categorized as either
Purines (double ring) or Pyramidines (single ringed). These are usually
represented by a letter. These Are:
Adenine (A)
Cytosine (C)
Guanine (G)
Thymine (T)
Base Pairing Rules
• Each "Rung" of the DNA "staircase" is formed by the linking
of 2 Nucleotides through Hydrogen Bonds.
• These Hydrogen bonds form only between specific
Nucleotides. This is known as Base Pairing. The rules are as
follows:
– Adenine (A) will ONLY bond to Thymine (T)
– Cytosine (C) will ONLY bond to Guanine (G)
Summary of DNA Structure
RNA
•
•
•
•
•
AKA ribonucleic acid
RNA differs from DNA in
several important ways.
It is much smaller
It is single-stranded
It does NOT contain
Thymine, but rather a new
nucleotide called Uracil
which will bind to Adenine.
ATP
•
•
•
Short for Adenosine Tri-Phosphate. ATP is
closely related to nucleic acids.
Composed of Ribose, Adenine & a phosphate
group
Phosphate group has ability to bind/release
additional phosphate group allowing it to store
or release energy