UNIT 1 –
UNDERSTANDING LIFE ON
EARTH
BIOMOLECULES
INTRO TO BIOCHEMISTRY
What elements from the periodic table
support all life on Earth?
Answer:
• CARBON
• HYDROGEN
• OXYGEN
• NITROGEN
• PHOSPHORUS
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Carbon-based Molecules:
Organic chemistry: study of
carbon compounds
Carbon has 4 electrons in an
outer energy level that
holds eight; Can form 4
covalent bonds with many
other elements
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Shape of Organic Molecules:
shape=function
The shape
determines its
function in an
organism
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Giant Molecules – Polymers:
•Large molecules are called
polymers
• Monomers link together
to form larger molecules
called polymers
• Biologists call polymers
macromolecules or
biomolecules
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Linking Monomers:
Cells link monomers by removing a molecule of water
this process is called dehydration synthesis.
Remove H
H2O Forms
Remove OH
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Breaking Down Polymers:
• Cells break down macromolecules by adding a
molecule of water
• this process is called hydrolysis
FYI
When trying to lose weight, dietitians tell patients to drink
more water to help in the breakdown and absorption of
molecules.
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Macromolecules in Organisms:
There are four macromolecules:
Carbohydrates (CHO)
Lipids (CHO)
Proteins (CHON)
Nucleic Acids (CHONP)
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CARBOHYDRATES
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Monosaccharides:
• Monosaccharides are the monomers of carbohydrates;
also called simple sugars
• Examples: glucose, fructose, & galactose
• Chemical Formula for monosaccharides is C6H12O6; this a
ratio of 1:2:1
• Monosaccharides are the main fuel that cells use for
cellular work; they are a source of quick energy
• Disaccharides (2 Sugars bonded); example – sucrose
(table sugar)
Polysaccharides:
Large sugar molecules; take longer for body to break down
• Starch is an example of a polysaccharide in plant cells
• Glycogen is a polysaccharide found in animal cells
• Starch and glycogen are extra amounts of sugar taken in by
the cell and stored for later use
• Cellulose is a polysaccharide found in plant cell walls;
most abundant organic compound on earth
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LIPIDS
Lipids:
• Lipids are hydrophobic –”water fearing”; they do not
mix with water
• Includes fats, waxes, steroids and oils
• Functions –
store energy
Insulate body
Cushion and protect organs
Form cell membranes
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Structure of Lipids:
• Triglyceride - Monomer of lipids
Composed of 1 glycerol molecule and 3 fatty acid chains
Glycerol forms the “backbone” of the triglyceride
• Triglycerides are composed mainly of carbon and
hydrogen; oxygen is found only in the glycerol
molecule
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Lipids in Organisms:
• Most animal lipids exist as solids at room temperature
(butter, lard, fat layer on steak/chicken, waxes)
• Most plant lipids tend to exist as liquids at room
temperature (peanut, sunflower, canola oils)
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Lipids & Cell Membranes:
• Cell membranes are made of
phospholipids
• Phospholipids have a head that is
polar; it attracts water (hydrophilic)
• Phospholipids also have 2 tails that
are nonpolar and do not attract water
(hydrophobic)
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Steroids:
• Cholesterol is the “base
steroid” from which your body
produces other steroids
• Estrogen and testosterone
are examples of these other
steroids
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PROTEINS
Proteins:
• Proteins are large, folded polymers made of monomers
called amino acids
• Elements in proteins: C, H, O and N
• Functions:
Build cells
Act as hormones
Act as enzymes
Cellular transport
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Linking Amino Acids:
•This process is done by the ribosomes in the cell by
removing a water molecule from the amino acids
•The process is called a condensation or dehydration
reaction; forms peptide bonds
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Enzymes are proteins
• What do enzymes do?
• Enzymes control the rate of chemical reactions
• Enzymes are also referred to as biological catalysts
• enzymes work by weakening bonds and lowering the
amount of activation energy needed for the reaction
• Enzymes act on a substrate; they are specific to
substrate
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Enzyme + Substrate = Product:
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NUCLEIC ACIDS
Nucleic Acids
•Store hereditary information
• Contain information for making all the body’s
proteins
• Elements in nucleic acids: C, H, O, N and P
• Types of nucleic acids: DNA and RNA
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• Nucleic acids are polymers; Nucleotides are the
monomers
• Nucleotides are composed of:
5-carbon sugar
phosphate group
nitrogeneous base
Nitrogeneous Bases:
•Each DNA nucleotide has one
of the following bases:
• Each RNA nucleotide has
one of the following bases:
– Adenine (A)
–Adenine (A)
– Guanine (G)
–Guanine (G)
– Uracil (u)
–Thymine (T)
– Cytosine (C)
–Cytosine (C)
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Shape of dna and rna:
• One strand of RNA forms a
single helix
• Two strands of DNA join
together to form a double
helix
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ATP
• ATP is the energy currency of cells
• Made of a nucleotide with 3 phosphate groups
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