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Macromolecules
The Large Molecules of Life
 Many macromolecules are comprised of Carbon atoms bonded to Hydrogen
atoms.
o Often there are long chains of these linked “hydrocarbons” that
form hydrocarbon chains, and are comprised of “carbon skeletons”.
o Organic molecules – molecules that contain carbon
 Methane
o Inorganic molecules – molecules that don’t contain carbon
 Water
Linking Monomers to make a
Polymer
 In order to link monomers a dehydration reaction must occur.
 A bond forms and water is lost.
 In order to break a polymer apart a hydrolysis reaction is required.
 A bond is broken when water is added.
Carbohydrates
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Major source of energy for all body activities
Made up of carbon, hydrogen and oxygen in a specific ratio 1:2:1
CH2O
Two categories: simple (sugars) or complex (starch, cellulose)
Simple Carbohydrates:
Monosaccharide (one sugar) and disaccharide (two sugars)
 Ex of monosaccharide: glucose, fructose, galactose, ribose.
 he ladder has the same chemical formula, but the structure is different
Disaccharides are composed when 2 monosaccharide bind together
Ex. Of disaccharide: sucrose, maltose, lactose
Complex carbohydrates:
Also called polysaccharide
Composed of many mono- and disaccharide molecules joined together in a longchained molecule
Ex. Starch, cellulose and glycogen
Functions of Carbohydrates
 Monosaccharides, especially glucose, are the main source of energy for the
body’s functions.
 Disaccharides need to be broken down into their monosaccharide components
to be used as energy
 Starch
- Form in which plants store glucose
- it can be digested by humans
 Cellulose
- Found in the cell wall of plant cells
- Cannot be digested by humans, however, it is a source of fiber
 Glycogen:
- Form in which animals store glucose
- Regulates glucose levels in blood
- W hen glucose level is too high, liver and muscles make glycogen.
Proteins
 A polymer comprised of monomers called amino acids.
 Amino Acids (a.a.):
 Building blocks of proteins
 Contain N, C, H, O
 There are 20 different a.a. linked together in different combination to form
different protein molecules
 Amino acids join together to produce polypeptide
 A protein consists of one or more polypeptides folded into specific
shape.
Functions of proteins:
 Support proteins
 Storage of amino acids
 Transport proteins – hemoglobin in blood transporting oxygen
Hormones – insulin produced by pancreas
 Receptor – response of cell to chemical stimuli
 Contractile proteins – movement in muscles
 Defensive proteins – antibodies that protect against disease
Enzymes
 Activation energy – the energy required to
“start up” a chemical reaction
 In order for certain chemical reactions to
occur, the activation energy must be
overcome.
 Enzymes are proteins that lower the activation
energy of reactions.
 They catalyze the reactions.
 Enzymes mimic a Lock and Key
 Each enzymes only fit into the active sites of certain substrates.
 The way that enzymes work can be affected by factors such as pH
and temperature.
 Environmental factors such as these can influence the structure of an
enzyme.
 Changing temperature or pH can cause a change in the size or shape
of an enzyme, and cause it to be ineffective.
 This is often the reason that cells and organisms need certain
conditions in order to survive.
 Enzymes are not used up or changed during their reactions; they
are reusable.
Lipids
 Hydrophobic molecules
o “water-fearing”
 Examples:
o Fats
 Saturated – in which each carbon has as many
hydrogens bonded to it as possible
 Unsaturated – in which each carbon does not
contain the maximum number of hydrogens bonded
 Instead there are double or triple bonds
o Steroids
 Testosterone, estrogen, cholesterol
 Cholesterol plays an important role in the
membranes of cells - gives them support
Nucleic Acids
 The basic units of polymers such as DNA and RNA