protein 2

Question 1

what are the three functions of protein

Answer 1

1. nutrition
2. texture
3. taste

Question 2

How is the function of meat proteins in the body related to the solubility of these proteins?

Answer 2

The function of muscle tissue is to give structure to the body. Therefore these proteins are not soluble

Question 3

How is the function of milk proteins related to the
solubility of these proteins?

Answer 3

The function of milk proteins is to give nutrition, since the calf will drink the milk, the proteins should be soluble

Question 4

what are peptides?

Answer 4

peptides are amino acid linked by peptide bonds

Question 5

what happens when pH<pKa

Answer 5

The acid. base is mostly protonated

Question 6

what happends when pH>pKa

Answer 6

the acid/ base is mostly deprotonated

Question 7

what forms the primairy structure of the protein

Answer 7

the primairy structure is formed by the peptide bonds, which are covalent bonds

Question 8

what forms the secondary structure of proteins

Answer 8

hydrogen bonds between C–O and NH groups in the peptide backbone

Question 9

what forms the tertiary and quarternary structure

Answer 9

• disulphide bonds (covalent S-S)
• electrostatic (stabelize or repel)
• hydrophobic interactions (non-polar residues have a tendency to aggregate in water)

Question 10

what influences the protein folding and stability?

Answer 10

• presence of reducing agent: can break the disulphide bridges
• temprature: can affect the hydrogen bonds
• solvent: change the hydrophobic interaction between molecules
• ph and isolectric point –> groups will attract and folded structure

Question 11

what happens when the pH is above or below the pI

Answer 11

the is an excess of negative/ positive charges –> this will result in repulsion and consequently unfolding of the protein