MACROMOLECULES PRO TEIN
Mar 28, 2015
MACROMOLECULES
PROTEI N
PROTEINS
Probably the most diverse group of macromolecules is the proteins.
PROTEINS
Proteins are complex polymers composed of C, H, O and N.
Polymer : large molecule formed when many smaller molecules bond together
FUNCTIONS OF PROTEINS• Serve as structural
components of animals, build and repair body tissue.
• Maintain cell growth• Serve as control
molecules (enzymes)• Serve as transport and
messenger molecules• Provide as energy if
sufficient carbohydrates and fats are not supplied by the diet.
• Ex. Keratin, elastin, collagen
PROTEINS• The building blocks
of proteins are smaller molecules called amino acids held together by peptide bonds
• Most end in “ine”• Despite the wide
variety of life on Earth, all living organisms use only 20 different amino acids to produce the proteins they require
PROTEINS
Green plants can make all 20 essential amino acids on their own; animals cannot.
Thus, animals, including humans, must get some of these essential amino acids from the foods they eat.
• All animal proteins are complete proteins: i.e. milk, eggs, cheese, fish and meat have all 9 amino acids.
• Proteins from some plant sources, such as brewer's yeast, certain nuts, soybeans (tofu is made from soybeans), cottonseed, and the germ of grains are also complete proteins.
• Partially complete proteins do not contain all 9 of the essential amino acids but a limited amount of one or more of them. Partially complete amino acids provide normal maintenance but will not support growth.
PROTEINS• Enzymes are
important proteins found in living things.
• An enzyme changes the rate of a chemical reaction.
• Enzymes are involved in nearly all metabolic reactions
• Usually end in “ase”
PROTEINS
Substrate- Component in an enzyme reaction
Enzyme reactions take place in the active site
Substrate + Enzyme Product + Enzyme
The enzyme is unchanged in the reaction.
PROTEINS
Each enzyme is specific to only one reaction.
This reaction is often compared to a lock and key.