IB Biology HL D2.1 Cell and Nuclear Division Question Bank
Practise IB Biology HL D2.1 by identifying cell-division stages, explaining meiosis outcomes and interpreting chromosome evidence.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Practise IB Biology HL D2.1 by identifying cell-division stages, explaining meiosis outcomes and interpreting chromosome evidence.
Which process contributes to growth of a multicellular body?
Exocytosis
Meiosis
Mitosis
Osmosis
C
Eukaryotes are a diverse group of organisms, including animals and plants.
Compare and contrast the processes of mitosis and cytokinesis in animal and plant cells.
Similarities: [6 max]
a. (in both plants and animals) produces two genetically identical daughter cells;
b. maintains the chromosome number/genome of cell / produces diploid/2n cells;
c. used for generation of new cells/cell replacement/tissue repair/growth;
d. in prophase the chromatin/chromosome condenses/formation of chromatids/supercoiling of chromosomes;
e. supercoiling of DNA around histones (to form nucleosomes);
f. microtubules/microtubule motors to move chromosomes/chromatids;
g. in metaphase chromosomes align in equator of cell;
h. in anaphase separation of chromatids;
i. in telophase two nuclei/cells form / nuclear membrane/envelope reforms
OR
cytokinesis is the division into two cells;
Differences:
j. in animal cell centrosomes/centrioles facilitates the organization of the mitotic spindle/ spindle poles/microtubules;
Marking points for 8c continued on next page....
Marking guidance:
Max 6 for similarities.
Allow clearly annotated diagrams.
8 max
8c continued ....
8.
c
k. in plant cells spindle fibres attach to walls;
I. in animal cells, the plasma membrane is pulled inwards around the equator to form a cleavage furrow in cytokinesis
OR
in animal cells actin and myosin pinch cell membrane to split cytoplasm/cytokinesis;
m. in plant cells a cell plate forms (at the equator) to develop into the new cell wall to achieve cytokinesis
OR
in plant cell vesicles (containing pectin) assemble sections of membrane/cell wall (at/across the equator) to achieve splitting/cytokinesis;
Ultraviolet (UV) light can penetrate cells, causing DNA damage. This effect can be reduced by using sunscreens or covering skin with clothing.
In an experiment to look at the effect of different treatments to reduce UV damage to DNA, yeast fungus (Saccharomyces cerevisiae) was used as the test organism. Six Petri dishes with agar were inoculated with yeast in sucrose solution. The Petri dishes were labelled according to the treatment applied to the lid, with sunscreen (Sun Protection Factors SPF15 or SPF50), cloth (polyester or cotton) or control (no treatment). Control 1 was placed in the dark and all the other Petri dishes were placed in direct sunlight for 6 hours. The dishes were then incubated for three days. The image shows yeast colonies that grew on the agar in one of the Petri dishes. The bar graph shows the number of yeast colonies present per Petri dish.


Describe how yeast cells reproduce.
a. budding;
b. asexual reproduction / mitosis;
c. unequal cytokinesis;
a. and b. Accept description of process.
Marking guidance:
Do not accept description of meiosis.
Do not accept (binary) fission.
2
max