Question 20N.2.HL.TZ0.b
| Date | November 2020 | Marks available | [Maximum mark: 4] | Reference code | 20N.2.HL.TZ0.b |
| Level | HL | Paper | 2 | Time zone | TZ0 |
| Command term | Outline | Question number | b | Adapted from | N/A |
Proteins are an important group of chemicals found in all living organisms.
Outline how proteins are digested and the products of protein digestion absorbed in humans.
[4]
a. digested by peptidases/proteases;
b. pepsin/pepsinogen/endopeptidase secreted by stomach (lining)/digests proteins in stomach;
c. pancreas secretes/pancreatic juice contains endopeptidase/trypsin/peptidase;
d. endopeptidase digest proteins/polypeptides to shorter chains of amino acids/shorter peptides;
e. amino acids absorbed by active uptake/transport;
f. in small intestine/ileum;
g. villi increase the surface area for absorption;
h. absorbed into bloodstream/into capillaries;
Peptidase can be accepted instead of endopeptidase in mpc, but not in mpb or mpd.
Nearly all candidates had some knowledge of protein digestion and many scored 3 or 4 of the 4-mark total. The relatively low mark allocation reflects that the program does not require detailed study of protein digestion or absorption. Few students referred to endopeptidases, which are stipulated in guidance for sub-topic 6.1 and also few stated that villi in the small intestine increase the surface area for absorption.
