Proteins Flashcards
What is the monomer for proteins?
Amino acids
What are the elements that make up proteins?
Carbon, Hydrogen, Oxygen, Nitrogen and sometimes Sulphur
How many proteins are proteinogenic?
20
What are the difference parts of an amino acid?
- An R-group
- An amino group
- A carboxyl group
What is the R-group?
It is a side chain added on to the amino acid
What is the bond between 2 amino acids?
It is a peptide bond with the C, O, N and H
What is the primary structure?
The sequence of amino acids are joined in a protein chain
What is the average chain of a primary structure?
100 amino acids
What are the bonds in the primary chains?
Peptide chains
What is the secondary structure?
It is the initial folding of singular polypeptide chains
What is the alpha helix structure?
The alpha helix is a secondary structure in a helix structure with 36 amino acids and 10 turns of the helix,
It has H bonds
Left hand is anticlockwise and right is clockwise
What are the bonds holding the secondary structures together?
Peptide bonds
Hydrogen bonds between the -NH groups and the -CO of another 4 places ahead the chain
What is the beta pleat structure?
Some fold slightly in a zig-zag structure, where the chains folds over in itself, forming a sheet like structure
It has H bonds
What is the tertiary structure?
This is when the coils and pleats start to fold, along with the areas of straight chains of amino acids.
It has a very specific shapes which are held together by bonds between close amino acids.
What is the tertiary structures shape?
Spherical
Supercoiled
What is the quaternary structure?
It is multiple polypeptide chains are arranged to make the complete protein molecule.
What holds a quaternary structure together?
Peptide bonds Hydrogen bonds Ionic bonds Disulphide links Hydrophilic and hydrophobic interactions
What holds a tertiary structure together?
Peptide bonds Hydrogen bonds Ionic bonds Disulphide links Hydrophilic and hydrophobic interactions
Where are the hydrogen bonds?
They are between an amino group and carboxyl group or between polar areas of the R- groups
Where are the ionic bonds?
Form between the carboxyl and amino groups that are part of R-groups. These ionise into NH3+ and COO- groups. The positive and negative ions cause the ionic bonds
Where are the disulphide links?
In between the R-groups of the amino acids cysteine contains sulphur, disulphide bridges are formed between the R-groups of 2 cysteine to make strong covalent bonds.
Where are the hydrophilic and hydrophobic interactions and why do they happen?
They happen when the R-groups are hydrophilic or hydrophobic.
If the R-group is hydrophilic it will mean it will be near the water
If the R-group is hydrophobic it will mean it will be away from the water
What are the features of globular proteins?
Compact
Roughly spherical
It is soluble
How is a globular protein formed?
It is when the proteins fold so hydrophilic R-groups are away from the water and the hydrophobic R-groups are close to the water