Proteins Flashcards
Primary structure
Thee primary structure of a protein is the sequence of amino acids
What shape is an alpha helix
It’s a coil shape that is kept stable by the hydrogen bonds which form between the n-h group and the c-o group.
How does hydrogen bonding occur in this?
The hydrogen in the -NH is slightly positive whereas the oxygen in the -C_-o is negative therefore forming weak interactions with each other resulting in hydrogen bonding between amino acids
What happens in alpha helix?
The polypeptide chains coil up and the hydrogen bonds keep the structure stable
What happens in beta pleated sheets?
The polypeptide bonds form a zig zag structure between themselves
Secondary structure of a protein definition .
The secondary structure of a protein is the curling or folding of the polypeptide chain into an alpha helix and a beta pleated sheets due to the formation of hydrogen bonds
Tertiary structure of proteins definition
The overall 3D shape of a protein. This is determined by interactions between R groups and properties of R groups
How are the structure of tertiary held in place
This is held in place by their r groups
How do ionic bonds from with t stucture
Between positive and negatively charged r groups
T structure bonds
Disulphide links form between sulphur acids ad r groups
Hydrogen bonds
Ionic bonds
What is this 3D shape determined by?
The hydrophilic and hydrophobic R groups.
Amino acids with hydrophilic r groups are found on the outside of the protein attract water where the hydrophobic r groups are away from the water and in the centre of the protein, creating this 3D shape
What may also be associated with polypeptide chains forming conjugated proteins?
Non-protein groups (prosthetic groups)
The quaternary structure of a protein
The specific 3D shape of a protein that is determined by the multiple polypeptide chains and/or prosthetic groups bonded together
What can happen by the change in temp and PH
This can result in the structure of proteins being altered or broken, and therefore being denatured . The shape is lost and can no longer carry out it function.
