Lab 1

Question 1

What are the 2 equations for working out dilution factor?

Answer 1

DF = Final volume(V2) / Volume of undiluted solution(V1)
DF = Undiluted conc.(C1) / Diluted conc.(C2)

Question 2

Which bonds stabilising salivary amylase are disrupted at 80° and how does this affect the protein structure?

Answer 2

The weak non-covalent bonds; hydrogen bonds, hydrophobic bonds, and ionic bonds.

As the protein cools, new random non-covalent bonds form, resulting in a misfolded protein that will bind to other misfolded proteins.

Question 3

Which bonds stabilising salivary amylase are disrupted by low pH and how does this affect the protein structure?

Answer 3

The intra-protein ionic bonds are disrupted as the ionisable amino acid side chains of the amylase protein become protonated.

This causes the amylase proteins to unfold, exposing their hydrophobic cores, making them less soluble and more likely to aggregate together.

Question 4

In the iodine starch test, which component of the starch causes a colour change to dark blue/black?

Answer 4

Amylose component

Question 5

In the iodine starch test, there is no colour change in the negative control, why?

Answer 5

The iodine has nowhere to bind as the starch solution is not present

Question 6

What causes the amylase protein to denature and how can this be observed in the iodine starch test?

Answer 6

High temperature and low pH. Observed by a colour change to deep blue/black

Question 7

What levels of protein structure are affected when chemical bonds are broken by heating at 80°?

Answer 7

Secondary, tertiary, and quaternary structure