Biochemistry
Exploring Macromolecules
Organic Chemistry
- study of chemistry of carbon
- molecules of life made of elements carbon,
oxygen, nitrogen, and hydrogen
- functional groups – determines the
characteristics of that compound
Hydroxyl goup: -OH (see fig. 2)
Carboxylic acid group: -COOH (see fig. 3)
Amine group: -NH2 (see fig. 4)
Large carbon molecules = macromolecules
- large polymers – composed of repeating units
called monomers
- monomers are joined in condensation or
dehydration synthesis reactions to form
polymers (fig. 5)
- breaking polymers down into monomers occurs
by hydrolysis reactions
- four main classes of macromolecules:
*Proteins * Carbohydrates * Lipids * Nucleic Acids
Proteins
- composed of amino acids = monomers
- all amino acids have a:
a. carboxyl group –COOH
b. amine group –NH2
- 20 common amino acids in living organisms
- joined by peptide bonds
= polypeptide
- sequence of amino acids
determines protein’s
structure and function
- [examples]
- primary structure = sequence of amino acids
- R groups often form attractions that cause the
protein to fold (add the following to handout)
- secondary structure = regular folding
- tertiary structure = irregular folding
- quaternary structure = more than one
polypeptide joined to make a functional
protein
- Denaturing a protein changes its shape
- change in temperature or pH
Primary structure
Hemoglobin
Secondary
(fig. 6 and 7)
Tertiary
Quaternary
Carbohydrate
- general formula Cn(H2O)
- provide energy
- exist as monosaccharides, disaccharide,
polysaccharides
- monomers = monosaccharides
(glucose/fructose)
- monosaccharides are linked by condensation
reactions
- sucrose is a disaccharide (fig. 8)
- three important polysaccharides
a. glycogen – animal energy
storage
b. starch – plant storage
c. cellulose – in plant cell walls
Lipids
- large nonpolar molecules that are not very
soluble in water
- very efficient energy storage molecules – store
twice as much energy as carbohydrates
- simplest are fatty acids with long, straight carbon
chain with a –COOH, carboxyl group, at one
end
- carbon chain is hydrophobic (water fearing)
- carboxyl group end is hydrophilic (water loving)
- form membranes of cells (phospholipids) (fig. 10)
- saturated fats have all single bonds
- unsaturated fats have some multiple bonds
- Four basic categories:
a. Triglycerides
b. Phospholipids
c. Waxes
d. Steroids – ex. Cholesterol and
hormones
Nucleic Acids
- transmit genetic information
- DNA and RNA
- DNA carries genetic
information from between
generations
- monomers are nucleotides
- each monomer has a sugar, phosphate group,
and a base (fig. 13)
- four bases in DNA in different orders code for all
characteristics of life!
- adenine, thymine, guanine, and cytosine (fig. 15)
- DNA is double helix
- hydrogen bonds hold
it together
- DNA is found in nucleus
(fig. 14)
- RNA is single stranded
- DNA codes for RNA
- RNA carries genetic code
to cytoplasm where it
codes for protein
synthesis