Transcript Unit One “Science Introduction & Cellular Function”

Unit One
“Science Introduction & Cellular
Function”
“Molecules of Life”
Monomers and Polymers
• Organic Molecule – a molecule formed by living
organisms that consist of a carbon backbone with
other elements bonded to it
• All four categories of macromolecules, which are
organic, are made from monomers that combine
to form polymers
• Macromolecules – very large molecules that are
necessary for the maintenance of the structure
and function of the cell
• Monomer – a subunit or “train car” that when
connected to others forms a polymer or “train”
Monomers and Polymers
• Polymer – a large molecule composed of many
subunits (“train cars”)
• All four categories of macromolecules connect
their monomers (subunits) in the same way:
– “Dehydration Synthesis” – making polymers from
monomers
• OH group is removed from one subunit and an H group is
removed from the other subunit
• Both the OH and H groups together compose water (H2O);
this is why this process is called “Dehydration”
• An enzyme (protein) is used to facilitate this reaction
Monomers and Polymers
• To breakdown a polymer the opposite of
Dehydration Synthesis occurs and is called
“Hydrolysis”
– Hydrolysis – reducing a polymer to its monomer
parts
• An OH and H group are added to opposite sides of a
subunit , therefore causing the polymer to be broken
into its monomer parts
Proteins
• Monomer = Amino Acid
• Polymer = Protein
• 20 common amino acids which differ by their
functional group
• Amino Acids are linked by “Peptide Bonds” (a
type of covalent bond), and are formed via
Dehydration Synthesis
• Long chains of amino acids linked by Peptide
Bonds are called “Polypeptides”
Proteins
• The way in which proteins function is determined
by the shape of the protein, which in turn, is
determined by what monomers bond with each
other
• There are four levels of protein structure that
determine functionality:
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–
Primary – long chain
Secondary – long chain folds
Tertiary – long chain folds and twists
Quaternary – more than one polypeptide chain
Proteins
• Proteins can only function in a specific range in
reference to temperature and pH
• If the temperature is too high, or the environment is
too acidic (low pH), then the protein unfolds and no
longer functions = “Denatured”
• Proteins are extremely important because they serve
as the “local government”: they ensure the proper
function of the cell
• Tertiary Proteins are Enzymes
• Enzymes act as catalysts, which govern cellular
reactions
Proteins
Nucleic Acids
• Monomer = Nucleotide
• Polymer = Nucleic Acid (RNA & DNA)
• The 5 Carbon Sugars of each Nucleotide are
linked by Phosphate Groups to form
Polynucleotide Chains = RNA and DNA
• RNA is found in viruses, and both RNA and DNA
are found in other species
• RNA is single-stranded
• DNA is double-stranded
Nucleic Acids
• Polynucleotide Chains (RNA and DNA)
function is essentially that of a library: these
macromolecules possess all the information
necessary to both form an individual and
maintain that individual throughout life
Nucleic Acids
Carbohydrates
• Monomer = Simple Carbohydrate
• Polymer = Complex Carbohydrate
• Carbohydrates purpose is to serve as an energy
supply for cells, and in some cases (polysaccharides),
to serve as a structural support to organelles in cells
• Simple Carbohydrates
– Monosaccharides – one monomer/subunit, Glucose is an
example C6H12O6
– Disaccharides – two monomers/subunits linked together
via dehydration reaction, Lactose is an example
Carbohydrates
• Complex Carbohydrates
– Polysaccharides – long polymer chains; Starch,
Glycogen, Chitin, and Cellulose
• Starch (plants) and Glycogen (animals) are storage
macromolecules for energy when energy is not
immediately needed by the organism’s cells
• Cellulose (plants) and Chitin (animals) are carbohydrate
macromolecules that assist with structural support of
organelles within the organism’s cells
Carbohydrates
“Glucose”
Lipids
•
•
•
•
Monomer = Fatty Acids and Glycerol
Polymer = Lipid or “Triglyceride”
Lipids are “Fats”
They are not soluble in water because of the
chemistry of their structure
• They are soluble in oil
• Lipids are composed primarily of Carbon and
Hydrogen atoms bonded to each other
Lipids
• Saturated Fat – each carbon is bonded to as
many hydrogen atoms as is possible
• Unsaturated Fat – not every carbon is bonded to
all hydrogens as is possible, and therefore, double
and triple bonds form between carbon atoms
• Lipids serve as long term energy storage for
cells, and also serve as the primary component
of all cells plasma membrane (barrier to outside
world)
Lipids