3.2 Molecules of Life
1.
2.
3.
4.
Carbohydrates
Proteins
Lipids
Nucleic Acids
3.2 Molecules of Life
1. Carbohydrates
•Composed of:
– Carbon, oxygen, and hydrogen in a ratio of
about
– 1 carbon to 2 hydrogen to 1 oxygen
•Monomer- monosaccharide
•Our main source of energy
•Used as structural materials in organisms
3.2 Molecules of Life
Carbohydrate
# of Monosaccharides
Example
Monosaccharide
Glucose (blood), fructose (fruit), galactose
(milk)
Disaccharide
Sucrose, lactose, maltose
Polysaccharide
Glycogen(liver + muscle), starch (plants),
cellulose (cell walls), chitin (exoskeletons of
arthropods)
3.2 Molecules of Life
Proteins
•Composed of:
– Carbon, hydrogen, oxygen, and nitrogen
– NO RATIO
•Monomer- amino acid
•Make up 50% of your dry weight
•Functions including structural, defensive,
and catalytic roles
3.2 Molecules of Life
• Examples:
– Enzymes: amylase, catalase, maltase
– Structural: collagen
– Contractile: actin, myosin (found in muscles)
– Transport: hemoglobin (transports oxygen in
the blood)
– Storage
– Hormones: insulin
3.2 Molecules of Life
• Amino Acids
– Proteins are made up of monomers called
amino acids
– The sequence of amino acids determines a
protein’s shape and function
Serine
Threonine
3.2 Molecules of Life
• Dipeptides and Polypeptides
– Two amino acids are joined by peptide bonds
to form a dipeptide
– A long chain of amino acids is called a
polypeptide
3.2 Molecules of Life
• Amino acid diagram
3.2 Molecules of Life
• Enzymes
– Speed up chemical reactions
– Bind to specific substrates (aka reactants)
– The binding of a substrate with an enzyme
causes a change in the enzyme’s shape and
reduces the activation energy of the reaction
– Typically named for the substrate they work
on + “-ase”
– The enzyme sucrase works on sucrose
– Factors that affect enzymes: heat or pH
3.2 Molecules of Life