1.4 Proteins

Question 1

What are amino acids?

Answer 1

• Monomers from which larger proteins are made
• Central C atom bonded to an anime group, R group, carboxyl group and H atom

Question 2

What are dipeptides?

Answer 2

• Two amino acids joined with a peptide bond
• Between carboxyl group of one and amino group of another
• Formed by condensation reaction, releasing a molecule of water

Question 3

What are polypeptides?

Answer 3

• Many amino acids joined with peptide bonds
• Formed by many condensation reactions, releasing many molecules of water

Question 4

Primary structure

Answer 4

Sequence of amino acids in the polypeptide chain, joined by peptide bonds

Question 5

Secondary structure

Answer 5

Folding of polypeptide into a-helix or B-pleated sheet, due to hydrogen bonds between amino acids

Question 6

Tertiary structure

Answer 6

3D folding of polypeptide chain, due to interactions between R groups (hydrogen/ionic/disulfide bonds)

Question 7

Quaternary structure

Answer 7

More than one polypeptide chain

Question 8

How do you test for proteins?

Answer 8

• Add biuret reagent
• Lilac if positive