Question 17N.2.HL.TZ0.a
| Date | November 2017 | Marks available | [Maximum mark: 4] | Reference code | 17N.2.HL.TZ0.a |
| Level | HL | Paper | 2 | Time zone | TZ0 |
| Command term | Describe | Question number | a | Adapted from | N/A |
Cell biologists play an important role in research into disease, fertility, evolution and many other areas of science.
Describe the origin of eukaryotic cells according to the endosymbiotic theory.
[4]
a. mitochondria and chloroplasts are similar to prokaryotes
b. «host» cell took in another cell by endocytosis/by engulfing «in a vesicle»
Allow “taking in” in place of “engulfing”
c. but did not digest the cell/kept the «ingested» cell alive
OR
symbiotic/mutualistic relationship «between engulfed and host cell»
d. chloroplasts and mitochondria were once independent/free-living «organisms»
e. DNA «loop» in chloroplast/mitochondrion
f. division/binary fission of chloroplast/mitochondrion
g. double membrane around chloroplast/mitochondrion
h. 70s ribosomes «in chloroplast/mitochondrion»
Award up to [2] for evidence from mpe to mph
[Max 4 Marks]
