Date | November 2017 | Marks available | 3 | Reference code | 17N.2.SL.TZ0.05 |
Level | Standard level | Paper | Paper 2 | Time zone | TZ0 / no time zone |
Command term | Discuss | Question number | 05 | Adapted from | N/A |
Question
State one disaccharide and the two monomers from which it can be synthesized.
Disaccharide:
1:
Monomers:
1:
and 2:
Discuss the roles of the enzymes secreted by the pancreas during digestion.
Compare and contrast cis-fatty acids and trans-fatty acids.
Markscheme
a. disaccharide name
eg: lactose, glucose and galactose
b. both monomers that make up mpa
eg: maltose, glucose and glucose
eg: sucrose, glucose and fructose
a. amylase breaks down/catalyzes/hydrolyses starch to maltose
b. lipase breaks down/catalyzes/hydrolyses fats to fatty acids and glycerol
c. proteases/peptidases break down/catalyze/hydrolyze proteins into smaller
polypeptides/dipeptides/amino acids
Award [2] if all three enzymes and substrates named correctly and one further mark for all three products named
correctly.
Allow specific enzymes
a. both are unsaturated fatty acids
OR
both have two carbon atoms joined by a double bond
b. in cis-fatty acids the two H atoms are on the same side while in trans-fatty acids they are on opposite sides
OR
cis-fatty acids are healthier than trans-fatty acids
OR
cis-fatty acids have a lower boiling/melting point than trans
OR
cis-fatty acids have a kink «in the chain» but trans do not
Accept answer in an annotated diagram