proteins Flashcards
what are proteins made of?
carbon
hydrogen
oxygen
nitrogen
some sulfur
what are the functions of proteins?
enzymes that catalyse reactions
carrier/transport proteins
antibodies
structural support for cells
hormone transmit information
enable muscles to contract
what are proteins?
polymers made up of amino acid monomers
how many different naturally occurring amino acids are there?
20
what does an amino acid contain?
amino group
R functional/variable group
carboxyl group
what bond is in a protein?
peptide bond
what is the primary structure of a protein?
a sequence of amino acids bonded by peptide bonds
forms a polypeptide
has no functions
what is the secondary structure of a protein?
alpha helix or beta pleated sheat
what is an alpha helix?
chains of amino acids coiled
stabilised by hydrogen bonds between carboxyl and amino groups
what are beta pleated sheets?
parts of amino acid chain are folded and lie next to each other
held in place by hydrogen bonds
what is the tertiary structure of a protein?
chains become folded into a globular or fibrous shape
(include areas of helix and pleated sheet)
what are the bonds in a tertiary structure?
hydrogen bonds
ionic bonds
disulphide bonds
where are the hydrogen bonds in a tertiary structure?
between OH and R groups
where are the ionic bonds in a tertiary structure?
oppositely charged amino acids form bonds due to positive or negative R groups
where are the disulphide bonds in a tertiary structure?
amino acid cysteine contains sulfur
between two sulfur atoms in two cysteines which are close together