[Biology SPM] Exam Pointers I

Source: Maths & Science Guide

Revision

1. State the effect of an enzyme on an oil molecule.
   
   
2. State two conditions that denatures an enzyme.
   
   
3. State the conditions of the valves during atrial systole.

Frequent Mistakes

Student's answer:

1. It converts it to fatty acid and glycerol.
   
   
2. Temperature and pH.
   
   
3. The valves close and the wall of the atria contract.

Tutor's comments:

1. The word "convert" does not convey the information that it is done with water being the reagent, and that it is a breakdown process. The correct terminology should have been "hydrolyses".
   
   
2. The student stated temperature and pH but did not give an indication on whether both conditions should be high or low.
   
   
3. The keyword here is "the conditions of the valves". Students should know that there are two types of valves - atrio-ventricular valves (bicuspid and tricuspid valves), and semilunar bases at the aorta and pulmonary artery.

Correct Answers

1. It hydrolyses it to fatty acids and glycerol.
   
   
2. Extreme temperature and extreme pH.
   
   
3. a) The semilunar valves close.
   b) The bicuspid and tricuspid valves open.