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Flashcards in Structure of a Protein Deck (17)
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What are the three different structures of protein?

Primary Structure
Secondary Structure
Tertiary Structure


What is the primary structure of a protein?

This is the number and sequences of amino acids in the polypeptide chain
Each of these are held together by a peptide bond
E.g Insulin has 51 amino acids


What is the secondary structure of a protein?

This is the further linking of the polypeptide chain with extra bonds or links
It gives the protein a definite 2 dimensional shape (normally spiral)
The links are called cross links or cross bonds
Two specific examples of cross bonds are disulfide bonds and hydrogen bonds


What shape is given to a protein if it contains cross links or bonds?

A 2-D shape


What allows a protein to have a 2-D shape?

Cross links or cross bonds


Name two types of cross bonds

Disulfide bonds
Hydrogen bonds


What is a disulfide bond?

This is where two amino acids containing the element sulphur link together
An example of an amino acid containing sulphur is cystine
The two sulphurs in the two cystines link together with a band called a disulphide bond
As a result of these disulphide links the chain coils into a two dimensional spiral shape.


A disulfide bond takes place between amino acids containing what element?



What is an example of an amino acid containing sulphur?



How do disulphide bonds bring about a 2D shape?

The bonds allow the protein to coil into a 2-D shape


What is a hydrogen bond?

These bonds occur when a hydrogen from one amino acid joins with a oxygen of another amino acid
This can occur on the one chain or between two neighbouring chains
A spiral shaped protein also result


What elements does a hydrogen bond form between?

Hydrogen and oxygen


What shapes results from hydrogen bonding?

A spiral shaped protein


How does hydrogen bonding result in a spiral shaped protein?

As hydrogen bonding can occur on the one chain of amino acids or between two neighbouring chains of amino acids


What is the tertiary structure of a protein?

This is the further folding and linking of the secondary structure to give the protein a three dimensional shape (normally fibrous or globular) i.e. more cross links to form to hold it in place.
It is only now that it starts to function as a protein


What structure does a protein have to have in order to function?

A tertiary structure


What are the two types of three dimensional shapes that are formed as part of the tertiary folding of a protein?

Fibrous or globular