Introduction
*Cells join smaller organic (Contains carbon) molecules together to form larger molecules.
*
These larger molecules, macromolecules, may be composed of thousands of molecules*The four major classes of macromolecules are: 1. Carbohydrates
2. Proteins 3. Lipids
Most macromolecules are
polymers
*Three of the four classes of macromolecules form chainlike molecules called polymers.
*The repeated individual units are small molecules called monomers.(beads on a necklace)
This process requires
energy ATP!!!!!) and is
helped out by
enzymes
*The covalent bonds connecting monomers in a polymer are broken apart by hydrolysis.
*As the covalent bond is broken a hydrogen atom and hydroxyl group from a split water molecule attaches where the covalent bond use to be.
*The covalent bonds connecting monomers in a polymer are broken apart by hydrolysis.
*As the covalent bond is broken a hydrogen atom and hydroxyl group from a split water molecule attaches where the covalent bond use to be.
Introduction to Carbohydrates
*Carbohydrates include both sugars and polymers. --Three types:
1. Monosaccharide: “simple sugars 2. Disaccharide: “double sugars” 3. Polysaccharides: polymers of monosaccharides
*Monosaccharides: Molecular formulas are in some multiple of CH2O
*Two monosaccharides can join with a to form a disaccharide via dehydration.
*Maltose, malt sugar, is formed by joining two glucose molecules.
Polysaccharides, the polymers of sugars, have storage
and structural roles
*Polysaccharides are polymers of hundreds to thousands of monosaccharides.
*One function of polysaccharides is as an energy storage macromolecule that is hydrolyzed as needed.
*Other polysaccharides serve as building materials for the cell or whole organism.
*Starch is a storage polysaccharide composed entirely of glucose monomers.
*Starches are insoluble in water and thus can serve as storage depots of glucose. Plants convert excess glucose into starch for storage.
*
Animals also store glucose in a polysaccharide
called
glycogen.
--Glycogen is highly branched.
*
Structural
polysaccharides form strong building
materials.
*
Cellulose
is a major component of the tough wall
of plant cells.
*The enzymes that digest starch cannot hydrolyze
the linkages in cellulose.
--Cellulose we eat will pass through as an “insoluble fiber.”
*Some microbes can digest cellulose to its glucose
monomers through the use of cellulase enzymes.
*Many herbivores, like cows and termites,
have
symbiotic relationships
with celluloytic microbes,
*Cellulose is probably the single most abundant organic molecule in the biosphere. It is the major structural material of which plants are made. Wood is largely cellulose while cotton and paper are almost pure cellulose.
*The result is a series of stiff, elongated fibrils - the perfect material for building the cell walls of plants.
*Chitin: In exoskeletons of arthropods (including insects, spiders, and crustaceans).
--Chitin is similar to cellulose, except it contains a nitrogen-containing appendage to each glucose.
Proteins
*Proteins are essential to organisms
--Structural support, storage, transport, intercellular signaling, movement, and defense.
*Humans have tens of thousands of different proteins, each with their own structure and function.
*All protein polymers are made from the same set of 20 monomers called amino acids.
R group Differences in R
groups produce the 20 different amino acids.
In most cases, the function depends on its ability to
recognize and bind to some other molecule.
EX #1: Antibodies bind to particular foreign substances that fit their binding sites.
EX #2: Enzyme recognize and bind to specific substrates, facilitating a chemical reaction.
Possible contributing factors are obstruction of vessels by sickled cells, increased venous and capillary pressure, bacterial infection and reduced oxygen-carrying capacity of the blood.
Introduction to Lipids
*Lipids are an exception among macromolecules—they don’t have polymers.
*They have little or no affinity to water.
--Structures are dominated by nonpolar covalent bonds.
*Highly diverse in form and function.
*Two types of molecules make up a fat: 1. Glycerol
Some important families of lipids are:
1. Fats
--Three fatty acids joined to a glycerol molecule.
2. Phospholipid
--Two fatty acids attached to glycerol and a phosphate group
