Question 20N.3.sl.TZ0.7
| Date | November 2020 | Marks available | [Maximum mark: 4] | Reference code | 20N.3.sl.TZ0.7 |
| Level | sl | Paper | 3 | Time zone | TZ0 |
| Command term | Classify, Deduce, Identify | Question number | 7 | Adapted from | N/A |
The diverse functions of biological molecules depend on their structure and shape.
Classify vitamins A, C and D as either mainly fat- or water-soluble, using section 35 of the data booklet.
[1]
all three correct ✔
Only a few very weak candidates answered this one wrongly.
The diverse functions of biological molecules depend on their structure and shape.
Deduce the straight chain structure of deoxyribose from its ring structure drawn in section 34 of the data booklet.
[1]
must be placed next to AND s on central carbons must be on same side (LHS or RHS) ✔
Accept crosses in place of on three middle carbons.
Very disappointing. I had only a few correct answers and the wrong ones very often showed no understanding at all. Some candidates drew ring structures even though a straight chain was requested.
The diverse functions of biological molecules depend on their structure and shape.
Sucrose is a disaccharide formed in the reaction of glucose with fructose.
Identify the reaction type and the newly formed functional group that joins the monosaccharide units in the product.
[2]
Reaction type:
condensation ✔
Accept “nucleophilic substitution/” for M1.
Functional group:
acetal/ether/glycosidic «linkage» ✔
Accept “glycoside” for M2.
Many candidates scored both marks here. Ether was the most common answer for M2 with some responding glycosidic.