Download NATURE`S BIOLOGICAL BUILDING BLOCKS

NATURE'S BIOLOGICAL BUILDING BLOCKS
CARBOHYDRATES
Composition: carbon, hydrogen, oxygen
Monosaccharides - usually 3-6 carbon atoms
These are the simplest sugars.
Hexoses: (6 C sugars) - glucose, fructose
Pentoses: (5 C sugars) - ribose, deoxyribose
Disaccharides - 2 monosaccharides joined together
sucrose = glucose + fructose
maltose = glucose + glucose
lactose = glucose + galactose
Polysaccharides - many monosaccharides joined in large molecule
cellulose - main component of wood
glycogen - main storgae form of glucose in liver
starch - main storage form of glucose in plants
chitin - main component of exoskeleton of insects, crayfish, lobsters, crabs and other
arthropods
LIPIDS
Composition: mostly carbon and hydrogen with some oxygen
Includes fatty, greasy and waxy compounds relatively insoluble in water, but soluble in
organic solvents such as ether and benzene.
Neutral Fats - high energy molecules consisting of glycerol and fatty acids.
Phospholipids - neutral fat with one fatty acid molecule replaced by phosphate, choline, or
other group. Important to membrane structure.
Carotenoids - red and yellow plant pigments such as carotene in carrots.
Steroids - lipids with carbon atoms arranged in four interlocking rings with side groups
attached. Includes cholesterol, bile salts, and sex hormones.
PROTEINS
Composition: carbon, hydrogen, oxygen, nitrogen and sometimes sulfur.
Composed of subunits (molecules) called amino acids joined together by a peptide bond.
Proteins may be structural (as in muscle tissue and connective tissue) or enzymatic. They
may also function as hormones.
ENZYMES: a group of proteins that catalyze chemical reactions.
Enzymes facilitate a reaction, but are not chemically altered by that reaction. Enzymes
have an active site that orients the reacting molecules and each enzyme is very specific
for which reaction it will catalyze. Almost all enzymes are protein; however, there are
many proteins that are not enzymes (see above).
NOTE: It has recently been discovered that there are ribonucleic acids with enzymatic
activity. Prior to this discovery, it was thought that all enzymes were protein.
NUCLEIC ACIDS
Atomic composition: carbon, hydrogen, oxygen, nitrogen, phosphorus
Molecular composition: polymers of nucleotides
nucleotide consists of:
nucleic acid base
(purine: adenine, guanine)
(pyrimidine: cytosine, thymine, uracil)
pentose (5 C sugar)
phosphate group
Examples: DNA is composed of A, T, G, C
RNA is composed of A, U, G, C
Nucleic acids store information.
Nucleotides store energy (ATP), and act as hormones (cAMP).