Biological Molecules- Proteins Flashcards
What are the monomers of proteins?
Amino acids
What is formed when two amino acids join together?
A dipeptide
What is formed when more than two amino acids join together?
A polypeptide
What are proteins made up of?
One or more polypeptides
What is in the general structure of an amino acid?
Carboxyl group, amine/amino group, R group (variable group)
How are polypeptides formed?
Amino acids linked together by condensation reactions to release one molecule of water and form a peptide bond between the carboxyl group of one amino acid and amine group of another
What is the primary structure?
Sequence of amino acids in the polypeptide chain
What is the secondary structure?
Hydrogen bonds form between amino acids in chain and coil into an alpha helix or fold into a beta pleated sheet
What is the tertiary structure?
Chain is coiled and folded further to form hydrogen bonds, ionic bonds and disulphide bridges
What is the quaternary structure?
Way that several polypeptide chains are assembled together
What are some examples of proteins with a quaternary structure?
Haemoglobin, insulin, collagen
What functions can proteins have?
Enzymes, antibodies, transport proteins, structural proteins
Enzymes
- Usually roughly spherical in shape due to tight folding of polypeptide chains
- Soluble
- Often have roles in metabolism
- Help synthesis large molecules
Antibodies
- Involved in immune response
- Two light polypeptide chains and two heavy polypeptide chains
- Variable regions, amino acid sequences vary greatly
Transport proteins
- Present in cell membranes
- Contain hydrophobic and hydrophilic amino acids which cause protein to fold up and form a channel
- Transport molecules and ions across membranes
