Protein Flashcards
What are amino acids made up of?
Amino group- H2N
Carboxylic acid group- COOH
R group- a change in R group changes the amino acid
How are amino acids joined together
Peptide bonding which is a condensation reaction and joins amino acids together
What is formed by many amino acids
A polypeptide
role of R groups
R groups are able to interact with each other forming different types of bonds. This leads to a long chain of amino acids folding into complex structures.
what is the Primary structure
Sequence of amino acids
what is the Secondary structure
Hydrogen bonds between amino group and carboxylic acid group cause the polypeptide to coil into different shapes.
what is the Tertiary structure
Folding of the protein into its final shape. This is where R groups interact with each other.
- hydrogen bonds
- ionic bonds
- disulfide bonds
- hydrophobic and hydrophilic interactions
what is the Quaternary structure
Proteins made of several polypeptide chains. The two subunits can be the same or different and can interact the same way as the tertiary structure.
Testing for protein
Place protein solution into a test tube and add biuret reagent. If positive a lilac solution is formed.
what are fibrous proteins
Fibrous proteins have a structural role and are made up of strong long chains. They are insoluble in water as they have a high proportion of hydrophilic r groups.
describe Keratin
A fibrous protein present in hair, nails and skin. There is a high proportion of cysteine a sulfur containing amino acid. There are many strong disulfide bonds forming forming strong, inflexible and insoluble material. The degree of flexibility is determined by the number of bonds.
describe Elastin
A fibrous protein found in elastic fibres which are in walls of blood vessels and in the alveoli of the lungs. They allow flexibility to expand but return to their original size. Elastin is a quaternary protein made from stretchy molecules called trapoelastin.
describe Collagen
Is a fibrous protein. It is a connective tissue found in skin, tendons, ligaments and the nervous system. They are all made of three polypeptides wound together in a long and strong rope structure. Collagen has flexibility.
what are Globular protein
Are compact, water soluble and usually roughly spherical in shape. R groups on the amino acid are kept away from aqueous environments. Hydrophilic R-groups are on the outside of the protein. This means they are soluble in water. They are used to regulating processes such as chemical reactions.
what is Insulin
Is a globular protein and a hormone that regulates blood glucose levels. Hormones are transported in blood and need to be soluble. Hormones have to bind to specific receptors on the cell surface membrane.
