Shirt P was washed at 150C, shirt Q at 350C, and shirt R at 650C. Shirt R, washed at the highest temperature, had the stain completely removed. Suggested changes to improve removal include washing at a higher temperature or adding more enzyme. The likely enzyme used is amylase, and a protease enzyme would be best for removing blood stains. Enzymes remove food stains by catalyzing reactions that break down the components of the stain.

1. Chapter 4: Chemical Composition of Cell
Section A
1. Diagram shows the results of an experiment in which three similar shirts P, Q and R with
identical fat stains were washed in an enzyme-containing washing powder at three
different temperature 150C, 350C and 650C.
a) (i) State the temperature at which each shirt P, Q and R was washed. [1m]
______________________________________________________________________
(ii) Explain your answer for each shirt. [3m]
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
b) Suggest two changes to the procedure which might have resulted in the complete
removal of the stain from shirt R. [2m]
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
c) (i) Name the enzyme likely used in the powder. [1m]
______________________________________________________________________
(ii) Suggest the type of enzyme that should be present in a washing powder designed to
remove blood stains. [2m]
______________________________________________________________________
d) How does enzyme in the washing powder remove food stains on the clothes? [1m]
______________________________________________________________________
______________________________________________________________________

2. 2. Diagram shows the structures of four organic compounds which are found in living cells.
a) (i) Name the structure of compounds X and Z. [2m]
______________________________________________________________________
(ii) State the monomer of X and Y. [2m]
______________________________________________________________________
b) What if pancreatic cells are unable to synthesis compound X? [1m]
______________________________________________________________________
c) (i) In the space below, draw and label the structure of the basic unit of organic
compound W. [2m]
(ii) Name two types of organic compound W. [2m]
______________________________________________________________________
(iii) State two structural differences between the organic compounds you named in c(ii)
[2m]
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________