3.1.4.1 Proteins

Question 1

What are the monomers that make up proteins?

Answer 1

Amino acids

Question 2

What is the structure of an amino acid?

Answer 2

Question 3

How many naturally occurring amino acids are there?

Answer 3

20

Question 4

What changes from amino acid to amino acid?

Answer 4

The variable group; the R group

Question 5

How are two amino acids joined?

Answer 5

By a peptide bond via a condensation reaction

Question 6

What is the primary structure of a protein?

Answer 6

The order of the amino acids in the polypeptide chain

Question 7

What changes the properties of a protein?

Answer 7

The sequence of the amino acids- the primary sequence.

Question 8

What is the secondary structure of proteins?

Answer 8

The sequence of amino acids either coil into an alpha helix or fold into a beta pleated sheet This is created by attracted hydrogen that bend the polypeptide chain

Question 9

What is the tertiary structure of proteins?

Answer 9

The further folding of the alpha helix or beta pleated sheet More bonds form- ionic bonds and disulfide bridges For proteins made up of only one single polypeptide chain this is their final 3D structure.

Question 10

What is a disulfide bridge?

Answer 10

This is one of the strongest types of bond, and is found in both the tertiary and quaternary structure

Question 11

What is the quaternary structure of proteins?

Answer 11

This is where multiple different polypeptides chains are assembled together. For proteins made up of multiple different polypeptide chains this is the final 3D structure

Question 12

How do you test for proteins?

Answer 12

Biuret Test

1. The test solution needs to be alkaline, so first a few drops of sodium hydroxide solution are added.
2. Then copper(II) sulphate solution is added. Protein present - solution turns PURPLE No protein present - solution stays BLUE

Question 13

What is the name for the test for proteins?

Answer 13

Biuret test