Proteins Flashcards
What is an amino acid
Monomer which makes up proteins. Central carbon atom bonded to carboxylic acid, amino group, hydrogen atom and R group
What is an amine group
The -NH2 group of amino acid
What is carboxyl group
The -COOH group of an amino acid
What is disulphide bridge?
Bond formed between sulphur atoms in R groups of amino acids
What is a hydrogen bond?
Chemical bond form between the positive charge on a hydrogen atom and the negative charge on another atom of adjacent molecule often between negative oxygen and positive hydrogen
What is ionic bond?
Bond between a positive iron, which has lost an electron and a negative iron which is gained electrons
What is a peptide bond?
Type of bond that is formed between two amino acids
What is a polypeptide?
Many immuno acids joined together by peptide bonds
What is the primary protein structure?
Sequence of amino acids that make up the polypeptides of a protein
What is a protein?
Polymer which is made up of amino acids linked by peptide bonds may also contain prosthetic groups as part of its return quaternary structure
What is the quaternary protein structure?
Number of polypeptide chains linked together and sometimes associated with non-protein groups to form protein
What is R group?
Each of the 20 immuno acids have a different R group determines the bonding that the amino acid can carry out
What is secondary protein structure?
The way in which the chain of amino acid of the polypeptides of, the protein is folded
What is the tertiary protein structure?
Folding of a whole polypeptide chain in a precise way, as determined by the immuno acid of which it is composed
Amino acids info
Monomers that make up protein. Only 20 amino acids present in all forms and the different combinations of these determines the shape and structure of each protein as well as its properties.
What happens when two amino acids join?
They join via a condensation reaction, and a peptide bond is formed, easing a water molecule. Two amino acids joined together is known as a dipeptide.
What is a polypeptide
More than two amino acids joined together
How are dipeptides and polypeptides broken down?
Through hydrolysis
What are the different levels of protein structure?
- Primary
- Secondary
- Tertiary.
- Query.
Primary structure, description
Number and sequence of amino acids in the polypeptide chain. Can determine the 3-D shape or tertiary structure and can therefore affect the shape of the active sites and enzymes.
Secondary structure, description
Hydrogen bonds form between amino acids in the chain. This causes it to coil into an alpha helix or fold into beta pleated sheets. The many hydrogen bonds make these structures stable. Most channel proteins are made of alpha Helices. 
Tertiary structure, description
This is a 3-D shape of the polypeptide chain. It creates a specific shape due to the sequence of amino acids in the chain is a hydrogen bonds, ionic bonds and disulphide bridges (covalent bonds) form between R groups. A change to the sequence of amino acids would affect the secondary and tertiary structure of these bonds would form in different places. All enzymes antibodies and some hormones have tertiary structure
Quaternary structure, description
If proteins are made of more than one polypeptide chain, then they are jointed together to create quaternary structure. Antibodies and haemoglobin are examples of these other non-protein groups may also be associated e.g. the haem group in haemoglobin 
What are fibrous proteins?
Long strands of polypeptide chains that have crossed linkage due to hydrogen bonds. They are insoluble. Little Or no tertiary structure. Limited number of amino acids with the sequence usually being highly repetitive 
Examples of fibrous proteins
Collagen, elastin and keratin
Collagen info
Three polypeptide chains has lots of covalent bonds, long, strong, flexible and insoluble chains lie close together
Elastin info
Insoluble, flexible, stretches, long, found in alveoli, blood vessels and skin
Keratin info
Long insoluble found in hair ,nails, claws, hooves and skin
What are globular proteins?
Spherical proteins that are somewhat water, soluble, and have a compact structure, one of the common protein types.
Pepsin info
Mainly beta sheets with Alpha helixes has two disulphide bridges. Tertiary structure, forms, active sites as its protease enzyme.
Insulin info
Transportable as it soluble. No beta sheets. Compact. Tertiary structure. hydrophobic core, hydrophilic exterior, lowers blood glucose
Haemoglobin info
Mostly alpha helixes. Compact. For polypeptide chains 2 alpha 2 beta.
3 globular protein
Pepsin, insulin and haemoglobin
