3.6 Structure Of Proteins

Question 1

What are proteins and what are they made up of

Answer 1

They are polymers made up of amino acids which are know as peptides

Question 2

What is the the structure of an amino acid

Answer 2

Carboxyl group
Anime group
R-group

Question 3

What is an R-group

Answer 3

Part of the amino acid that determines what type of amino acid it is

Question 4

How do peptides synthesise and what’s the bond Called

Answer 4

The hydroxyl group of the carboxylic acid group will react with the H in the Amine group of another amino acid this is a condensation reaction
This creates a peptide bond creating a dipeptide

Question 5

What are peptide bond catalysed by to become polypeptides

Answer 5

The enzyme peptidyl transferase

Question 6

What happens to the R-groups when lots of peptides bond to form a polypeptide

Answer 6

The different r groups will interact with each other and form different bonds which will start to form specific complex shapes

Question 7

What is the primary structure of a proteins

Answer 7

The amino acid sequence which determines the folding and function of the protein
The only bonds involved are the peptide bonds

Question 8

What is the secondary structure of the protein

Answer 8

Here the oxygen and hydrogen atoms interact creating hydrogen bonds within the chain which pull it into either a coil shape (alpha helix)
Or the polypeptides will lie next to each other and appear pleated creating the beta pleated sheet

Question 9

What are the 2 structures that can be created in the secondary structure of a protein

Answer 9

Beta pleated sheet

Alpha helix

Question 10

What happens in the tertiary structure of a protein

Answer 10

The folding of the polypeptides bring the r groups close enough together to interact and new bonds start

Question 11

What bonds happen when the r groups interact

Answer 11

Hydrophobic/hydrophilic (these are weak)
Hydrogen bonds
Ionic bonds between the oppositely charged r groups
Disulphides bonds which are covalent and only happen in the sulfur containing r groups

Question 12

What is the quaternary structure of a protein

Answer 12

It’s final structure where the protein subunits have been made and 2 protein subunits will interact and the same interactions that happened in the tertiary structure will happen between the 2 protein molecules

Question 13

What is layer chromatography

And what does the rate of movement depend on

Answer 13

It separates amino acids
There are 2 phases the stationary phase and mobile phase
Rate of movement depends on the hydrogen bonds

Question 14

How do you breakdown peptides and what enzyme is used

Answer 14

Through a hydrolysis reaction

Proteases catalyse the reverse reaction of peptide bonding

Question 15

How do you identify proteins

Answer 15

Using the biuret test

Violet is the colour