Know me slide 4 Flashcards
macromolecules
Another level in the hierarchy of biological
organization is reached when small organic
molecules are joined together into
macromolecules.
*Four main classes of macromolecules are:
1) Carbohydrates
2) Lipids
3) Proteins
4) Nucleic Acids
Monomers and Polymers
A polymer (poly = many) is a long molecule consisting of many similar molecular building blocks called monomers (mono = one).
The* vast diversity of life’s polymers
are constructed of
only about 40 to 50 monomers.
Each class of polymer is formed
from a specific set
of monomers.
Although organisms share the same limited number
of monomer types,
each organism is unique based
on the arrangement of monomers into polymers
dehydration reactions
Monomers are connected into larger molecules by special
reactions called dehydration reactions
Dehydration reactions also yield
a water molecule (-H + -OH)
hydrolysis reactions
Polymers break down into monomers by hydrolysis reactions.
Hydrolysis consumes
a water molecule.
hydolysis
adds a water molecule, breaking a bond
*Carbohydrates
include both simple
sugars and polymers of these.
Monosaccharides “one sugar”
-Are monomers of carbohydrates – Are the simplest sugars – Can be used for fuel – Can be converted into other organic molecules – Can be combined into polymers
Examples of Monosaccharides
aldoses, ketoses, triose sugars, pentose sugars, hexose sugars,
Sugars vary in the
position of
carbonyl groups
Sugars vary in the
length of carbon
skeletons
Dissacharides
consist of two monosaccharides
joined by a glycosidic linkage
glycosidic linkage
a covalent bond
formed by a dehydration reaction
Polysaccharides
are sugar polymers that serve
many energy storage and structural functions.
Polysaccharides can consist
of several thousand
monosaccharides joined by glycosidic linkages
Storage
Polysaccharides
• Starch is the major storage form of glucose in plants • Composed of two forms: amylose and amylopectin
Glycogen is the
major storage form of
glucose in animals
Highly branched
chain of glucose
monomers
Cellulose,
the most
abundant organic
compound, is a long
chain of glucose.
Cellulose has different glycosidic linkages than starch
Hydrogen bonding among cellulose molecules form them
into cable-like units called microfibrils.
No animals possess
enzymes to break down
cellulose.
Some animals house
bacteria in their digestive
tracts that allow them to
digest cellulose
Chitin
is a structural
polysaccharide in the
exoskeletons of insects
and other arthropods
chitin is used
to make a strong and flexible surgical thread that decompses after the wound or incision heals
Chitosan derived from crustacean chitin
has many industrial,
agricultural, and biomedical uses.
Chitosan derived from crustacean chitin
has many industrial,
agricultural, and biomedical uses.
Lipids
Do not consist of polymers
-Lipids are a diverse group of hydrophobic
molecules (little or no affinity for water)
• Mostly composed of hydrocarbons (non-polar)
3 *types of lipids
-Fats
– Phospholipids
– Steroids
Fats
• Fats function in energy
storage
fats
Constructed from two types of smaller molecules, a single glycerol and usually three fatty acids
fatty acids
are
composed of carboxyl
functional groups and
hydrocarbon chains
Saturated fatty acids
-Have the maximum number of hydrogen
atoms possible (no double bonds)
• Are solid at room temperature
• Animal fats
Unsaturated fatty acids
- Have one or more double bonds
- Liquid at room temperature
- Plant fats
Phospholipids
are similar to fats but have only two fatty acids attached to glycerol.
Because the two ends
of phospholipids show
different behavior
toward water
they self assemble
into bilayers
and other boundaries
between environments.
phospholipid
bilayers.
The membranes of
cells are phospholipid
bilayers.
Steroids
Steroids are lipids characterized by a carbon
skeleton consisting of four rings.
Functional groups give steroids
various structural
roles (e.g. cholesterol) and regulatory roles (e.g.
sex hormones).
