Question 17N.2.HL.TZ0.06
| Date | November 2017 | Marks available | [Maximum mark: 15] | Reference code | 17N.2.HL.TZ0.06 |
| Level | HL | Paper | 2 | Time zone | TZ0 |
| Command term | Compare and contrast, Describe, Outline | Question number | 06 | 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]
Cell biologists play an important role in research into disease, fertility, evolution and many
other areas of science.
Compare and contrast the processes of spermatogenesis and oogenesis.
[8]
a. both result in haploid cells/gametes
b. both involve mitosis at the start/in the «germinal» epithelium
c. both have cell growth «before meiosis»
d. both involve «two divisions of» meiosis
e. both involve differentiation to produce a gamete
f. both are stimulated by hormones
OR
spermatogenesis stimulated by testosterone and oogenesis stimulated by FSH
A table is not required but both statements in one row of the table must either be explicitly stated or clearly implied to award the mark
[Max 8 Marks]
Cell biologists play an important role in research into disease, fertility, evolution and many
other areas of science.
Outline the evidence for evolution provided by selective breeding.
[3]
a. crop plants/domesticated animals/livestock produced by selective breeding
b. specific example of a domesticated animal/crop plant and the wild species from which it
was developed
OR
specific example of a domesticated animal/crop plant and the features in it which have been improved «compared with the wild species»
For example dogs have been developed from wolves
c. artificial selection/crossing selected varieties/eliminating undesirable varieties
d. «selective breeding/artificial selection can cause» significant/rapid change over time/from the original wild species
e. «changes due to selective breeding/artificial selection» shows natural selection can cause change/evolution «in a species»
[Max 3 Marks]