amino acids, r groups, structures #3 Flashcards
amino acids
monomers that build protein polymers
how do amino acids differ
the chemical structure of the R group
-amino acids all have the same structure
the r group
gives each amino acid its chemical properties
- MAY contain S and/or P
if the r group is polar
polar- has a negative and positive end
- the amino acid will be hydrophilic (water loving)
- found on outside of protein
if the r group is non-polar
non-polar- no charged ends
- the amino acid is hydrophobic (water hating)
- found on inside of protein
how are the amino acids joined
by peptide bonds
many amino acids join together to form…
a polypeptide with the R group as the side chains of the molecule
protein structure
- primary structure
- secondary structure
- tertiary structure
- quaternary structure
primary structure
the order of the amino acids in the protein
- determined by the order of the bases in the DNA
- different for each protein
secondary structure
sections of the amino acid chain can fold in on of 3 different ways.
- alpha (a) helix- a spiral molecule
- beta (b) pleated sheet
- random coil (irregular parts that link a helices and b pleated sheets)
tertiary structure
the irregular 3D shape of the entire polypeptide chain with 2 or more secondary structures.
tertiary structure pt2 - what is the shape a result of
the bonding between different R-groups
- hydrophilic R groups attract each other as do hydrophobic R groups (like attracts like)
- this causes the polypeptide chain to fold
tertiary structure pt3 - if the protein is found in an aqueous environment
- hydrophobic R groups are concealed within the interior of the protein
- hydrophilic R groups are on the outside
quaternary structure
the overall protein shape where two or more polypeptide chains interact to form a 3D protein
- the polypeptide chains can be different or identical
quaternary structure pt2 - when u can’t sure ‘protein’
one polypeptide chain of a protein with a quaternary structure is not functional
using the word ‘protein’
you must NOT use the word protein to describe the molecule until it is in its final state and functional
denaturation
proteins lose shape, folding, protein function
how can proteins change in shape
when exposed to high temperatures, changes in pH or altered salt conditions
- having just one different amino acid causes a protein to fold differently.
