macromolecules the building blocks of life…. macromolecules cells are composed of several types of...
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Macromolecules
Cells are composed of several types of biological macromolecules.
These function as energy-storage molecules, structural components, and in information storage, and are primarily composed of carbon, hydrogen and oxygen.
Carbohydrates
carbon, hydrogen & oxygen in a 1:2:1 ratio exist as monosaccharides, disaccharides
and polysaccharides among the most abundant molecules on
Earth
Monosaccharides
“single sugars” general formula is
(CH2O)n
glucose (top) and ribose (bottom) are monosaccharides
O
OH
HH
H
OH
OH
H OH
H
OH
O H
OHH
OH
H
OH
H
OH
Disaccharides
“double sugars” formed by dehydration synthesis from two
monosaccharides sucrose, maltose, and lactose are all
disaccharides
Synthesis of MaltoseO
OH
HH
H
OH
OH
H OH
H
OH
O
OH
HH
H
OH
OH
H OH
H
OH
O
OH
HH
H
OH
H OH
H
OH
O
O
HH
H
OH
OH
H OH
H
OH
-glucose - glucose
maltose
Polysaccharides
straight or branched chains of monosaccharides connected by glycosidic linkages
storage (e.g. starch, glycogen) or structural (e.g. cellulose, chitin)
Proteins
proteins are chains of amino acids connected by peptide linkages
order of amino acids for a particular protein is determined by the gene which codes for it
Amino Acid Structure
all amino acids have the same basic structure
“R” group is different for each amino acid
NH2
H
R
O
OH
carboxyl group
amino group
Secondary the folding or coiling
of the amino acid chain
caused by interactions between “R” groups
-Helix -Pleated Sheet
Tertiary the unique three-
dimensional shape of the protein
enzymes are globular proteins
collagen is a fibrous protein
Quaternary interactions between
separate polypeptide chains, or “subunits”
hemoglobin is composed of four subunits
Lipids lipids are a group of hydrophobic
molecules “neutral fats” are uncharged lipids
composed of glycerol and fatty acids fats are solid at room temperature oils are liquid at room temperature steroids and phospholipids are amphiphilic
Steroid Structure
steroids all have the same basic structure of four fused hydrocarbon rings
cholesterol is used to synthesize many other steroids in the body
CH3
OH
CH3
CH3
CH3
CH3
cholesterol
Phospholipid Structure
glycerol backbone has two fatty acids and one charged inorganic phosphate group attached
primary component of cell membranes
Triglycerides triglycerides are neutral fats glycerol is the “backbone” molecule fatty acids attach to glycerol by ester
linkages saturated fatty acids have no double
bonds between carbons unsaturated fatty acids have at least one
double bond between carbons
Triglyceride Synthesis
OH
OH
OH
CH3
O
OH
CH3
O
OH
CH3
O
OH
O
O
O
O
O
O
CH3
CH3
CH3
glycerol3 fatty acids
ester linkage
triglyceride
Nucleic Acids
Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA)
composed of nitrogen-containing “bases” attached to a backbone of alternating pentose sugars and inorganic phosphate
function in information storage (DNA) and transfer (RNA)
“Bases” of DNA & RNAPurines Pyrimidines
adenine thymine
guanine cytosine
uracil
N
NN
NH
NH2
N
NHN
NH
NH2
O
NH
NHCH3
O
O
NH
N
NH2
O
NH
NH
O
O
References MIT Biology Hypertextbook(1996)
http://esg-www.mit.edu:8001/esgbio/lm/sugars/sugars.html (3/9/2001)
Farabee, M.J., (2001) An Online Biology Book. Chemistry 2: Water and Organic Molecules http://gened.emc.maricopa.edu/bio/bio181/BIOBK/BioBookCHEM2.html (3/9/2002)
A.C.D. Labs (2002) ChemSketch (Freeware), available for download at http://www.acdlabs.com/. Used for molecular structure diagrams.