Organic Compounds of life:
• 4 Types: Carbohydrates, Lipids,
Proteins & Nucleic acids
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CARBOHYDRATES:
• Includes: Sugars, starches,
cellulose & glycogen
• Made of Carbon ( C ), Hydrogen ( H
), and Oxygen (O )
• Following ratio of elements CnH2nOn
o Sugars: Provide & store energy
for cells
o Simple sugars include Glucose &
Fructose since these are made of only 1 Carbohydrate molecule they are known
asMonosaccharides.
• Monosaccharides can be linked
together through the process of Dehydration Synthesis
o 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
o Often referred to as transport
saccharides
o Require some digestion to be used by
cells
Dehydration Synthesis
• Starches are many monosaccharides
linked together in a single chain. These are called Polysaccharides.
o Plants use this for energy storage
e.g. Potatoes
o Two types
Amylose - Long strait unbranched
chains
Pectins - many linked short Amylose
chains
Starch
• Cellulose is made of long
polysaccharide chains
o Plants use this for structure (e.g.
Wood) - not very digestible
o Due to the reverse orientation of
the monosaccharide sububnits, digestive enzymes cannot hydrolize the bonds
between them
Cellulose
• Glycogen is a moderately branched
polysaccharide
o Animals use this for energy storage.
Glycogen
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Lipids:
• Lipids are macromolecules including
fats, waxes & oils
o Primary function is energy storage.
Energy is stored in C-H bonds.
More efficient in storing energy
o Lipids are made of 2 parts
Glycerol - an alcohol - Serves as
backbone of the molecule
3 Fatty acids - Long hydrocarbon
chains
• 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.
• 4 Major 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.
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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
example amino acids
• Amino acids form proteins via
deyhdration sythesis 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
• 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.
o Primary Structure of a protein is
it’s sequence of amino acids.
o 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.
o The protein then can compact and
twist on itself to form a mass called it’s Tertiary Structure
o Several Proteins then 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.
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Nucleic Acids
• Two types of Nucleic acids
• DNA (Deoxyribonucleic Acid)
• RNA (Ribonucleic acid)
o DNA is Formed of in a "Double
Helix" - like a spiral staircase.
DNA Molecule-note "double
helix" shape
• DNA is formed by Nucleotides
o These are made from 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
• 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:
o Adenine (A)
o Cytosine (C)
o Guanine (G)
o Thymine (T)
• 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:
o Adenine (A) will ONLY bond to
Thymine (T)
o Cytosine (C) will ONLY bond to
Guanine (G)
• RNA differs from DNA in several
important ways.
1. It is much smaller
2. It is single-stranded
3. It does NOT contain Thymine, but
rather a new nucleotide called Uracil which will bind to Adenine.
Comparison of DNA & RNA
• ATP is closely related to nucleic
acids.
• Composed of Ribose, Adenine & a
phosphate group
o Phosphate group has ability to
bind/release additional phosphate group allowing it to store or release energy.
