1.2 protien Flashcards
protein
a biological
macromolecule
composed of amino
acid monomers linked
by covalent bonds
amino acid
an organic
molecule composed of
a central carbon atom
bonded to a hydrogen
atom, an amino group,
a carboxyl group, and a
variable R group
why are some amino acids called essential amino acids
because they cannot be produced by the human body
and must be consumed as part of the diet. !ese are isoleucine, leucine, lysine, methionine,
phenylalanine, threonine, tryptophan, and valine.
what determines a proteins function
The
properties of the side
chains on the amino acids
determine the overall
shape of the protein and,
therefore, its function.
polypeptide
a
polymer composed
of many amino acids
linked together by
covalent bonds
the structure of a protein can be divided into four levels of organization. What are they?
Primary Structure, secondary, tertiary and Quaternary Structure
what reaction happens in a peptide bond
condensation
primary structure fomation
sequence of amino acids in a polypeptide chain
secondary structure formation
folded structure within a polypeptide due to HB interaction between carbonyl O of one amino acid with the amino H of another. Alpha helix and beta pleated sheet are secondary structures.
Tertiary structure formation ( hard)
Most of the protein folding process occurs
naturally as the peptide bonds and the di#erent R groups in a polypeptide chain interact
with each other and with the aqueous environment of the cell. Most of what determines
tertiary structure is the hydrophobic e#ect. For example, polar hydrophilic groups will be
directed toward the aqueous environment, while non-polar hydrophobic groups will tend
to be directed toward the interior of the protein’s three-dimensional shape. !ere are also
other stabilizing forces, such as hydrogen bonding between R groups of di#erent amino
acids and electrostatic attractions between oppositely charged R groups.
quaternary structure formation
basically tertiary but with many polypeptide chains (subunits)
Under certain conditions, proteins can completely unfold in a process called?
denaturation
when does Denaturation occur
when the normal bonding between R groups is
disturbed. Intermolecular bonds break, potentially a#ecting the secondary, tertiary, and
quaternary structures. Conditions that can cause denaturation include extremes of hot
and cold temperatures and exposure to certain chemicals. Once a protein loses its normal
three-dimensional shape, it is no longer able to perform its usual function.