Biological termModerate1 mark
1(a)
Name the following:
The process of transformation of several glucose molecules into one molecule of starch.
Topic: Polymerisation
Previous-year question practice database
Answer
Exam answer
POLYMERISATION.
Explanation
Polymerisation is the joining of many small identical molecules (MONOMERS) into one large molecule (a POLYMER). Here many glucose monomers are linked into one molecule of starch.
WHY THE PLANT DOES IT: glucose is soluble and osmotically active, so storing large amounts of it would upset the water balance of the cell. Starch is INSOLUBLE and compact, so it can be stored in quantity without disturbing osmosis.
The same principle appears elsewhere in the syllabus: animals store glucose as GLYCOGEN for exactly the same reason.