1.6- Proteins

Question 1

Describe the structure of an amino acid

Answer 1

• Amino group
• Carboxyl group
  -Hydrogen atom
  -R group

Question 2

How is a dipeptide formed

Answer 2

Two amino acids bonded together by a peptide bond between the carbon atom of one amino acid and the nitrogen atom of another formed by a condensation reaction

Question 3

Describe the primary structure of a polypeptide

Answer 3

The sequence of amino acids in the polypeptide chain

Question 4

Describe the secondary structure of a polypeptide

Answer 4

Folding of the polypeptide chain into alpha helix or beta pleated sheet due to the formation hydrogen bonds

Question 5

Describe the tertiary structure of a polypeptide

Answer 5

Further folding of the polypeptide chain due to the formation of hydrogen bonds ionic bonds and disulfide bridges

Question 6

Describe the quaternary structure of a polypeptide

Answer 6

The way that the polypeptide chains are assembled together
Final 3D structure

Question 7

Describe the test for proteins

Answer 7

Place the sample in a test tube and add an equal volume of sodium hydroxide
Add a few drops of dilute copper sulphate solute and mix
The purple colour indicates the presence of a protein