D2.1 Cell and nuclear division questions for IB Biology
45 questions on Cell and nuclear division, written by Augment in the style of IB exam papers. Six of them are below in full, to answer on paper.
- IB Biology
- Part of D Continuity and change
- SL and HL
Questions by paper and level
SL and HL questions are for students at either level. HL only questions cover what only HL students study.
| Paper | SL and HL | HL only | All |
|---|---|---|---|
| Paper 1A | 13 | 7 | 20 |
| Paper 1B | 3 | 2 | 5 |
| Paper 2 | 13 | 7 | 20 |
| Every paper | 29 | 16 | 45 |
Counted on
Questions to try
Written by Augment in the style of IB exams, not past papers. Answer them on paper, then check each one against its markscheme with a free account.
Which row describes how cytokinesis is achieved in animal cells and in plant cells?
Row | Animal cell | Plant cell |
|---|---|---|
A | vesicles fuse to form a cell plate | a ring of actin and myosin pinches the membrane inwards |
B | a ring of microtubules pinches the membrane inwards | vesicles fuse to form a cell plate |
C | a ring of actin and myosin pinches the membrane inwards | vesicles bring membrane and wall material to the equator |
D | a ring of actin and myosin pinches the membrane inwards | the cell wall constricts inwards to divide the cytoplasm |
Students investigated the effect of caffeine on cell division in onion (Allium cepa) roots. Onion bulbs were grown with their bases in water until roots were 2 cm long, then transferred to caffeine solutions of different concentrations for 24 hours. Five roots were taken from each concentration and the tips were stained and squashed. In each root tip, 500 cells were examined with a light microscope and the number of cells containing two nuclei (binucleate cells) was recorded.
Caffeine concentration / % | Mean binucleate cells / % | Standard deviation / % |
|---|---|---|
0.00 | 0.2 | 0.2 |
0.05 | 1.8 | 0.6 |
0.10 | 4.6 | 1.1 |
0.20 | 9.4 | 1.8 |
0.40 | 10.1 | 2.4 |
- (a)
Identify the dependent variable in this investigation.
1 mark
- (b)
Outline the reason for including roots grown in 0.00 % caffeine.
1 mark
- (c)
Calculate the percentage increase in the mean percentage of binucleate cells when the caffeine concentration was increased from 0.10 % to 0.20 %.
1 mark
- (d)
A student concluded that 0.40 % caffeine has a greater effect than 0.20 % caffeine. Evaluate this conclusion using the data.
2 marks
- (e)
Caffeine is known to prevent the formation of the new cell wall between daughter cells. Explain how this results in binucleate cells.
3 marks
Variation is the raw material on which evolution acts.
- (a)
Describe how meiosis generates genetic variation.
4 marks
- (b)
Outline how the selective breeding of crop plants provides evidence for evolution.
4 marks
- (c)
Explain how natural selection can lead to evolutionary change in a population.
7 marks
Which is an example of unequal cytokinesis?
Students investigated division in baker's yeast (Saccharomyces cerevisiae), which reproduces by budding. Yeast was grown in a 2 % glucose solution and samples were viewed at ×400 magnification. For six pairs of cells at the moment the bud separated from its mother cell, the diameters of the mother cell and of the bud (daughter cell) were measured using a calibrated eyepiece graticule.
Pair | Diameter of mother cell / µm | Diameter of daughter cell / µm |
|---|---|---|
1 | 5.4 | 3.9 |
2 | 5.0 | 3.6 |
3 | 5.6 | 4.1 |
4 | 5.2 | 3.7 |
5 | 4.8 | 3.5 |
6 | 5.4 | 4.0 |
Mean | 5.2 |
- (a)
Calculate the mean diameter of the daughter cells.
1 mark
- (b)
Assuming the cells are spheres, calculate how many times greater the volume of a mother cell of mean diameter is than the volume of a daughter cell of mean diameter. The volume of a sphere is .
2 marks
- (c)
Suggest one source of error in measuring the diameters of yeast cells in this way.
1 mark
- (d)
Suggest one way to improve the reliability of the results.
1 mark
- (e)
Explain why budding is described as unequal cytokinesis, and why the bud must receive at least one mitochondrion.
3 marks
- (f)
State one example of unequal cytokinesis in humans.
1 mark
Species are units of biodiversity, but defining them is not straightforward.
- (a)
Outline how geographic isolation can lead to the formation of new species.
4 marks
- (b)
Discuss the difficulties of deciding whether two populations belong to the same species.
7 marks
- (c)
Describe how meiosis halves the chromosome number, and explain why diploid cells have an even number of chromosomes.
4 marks
Practice all 45 in Augment
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More questions in Continuity and change
- D1.1DNA replication
- D1.2Protein synthesis
- D1.3Mutations and gene editing
- D2.1Cell and nuclear divisionThis page
- D2.2Gene expressionHL only
- D2.3Water potential
- D3.1Reproduction
- D3.2Inheritance
- D3.3Homeostasis
- D4.1Natural selection
- D4.2Stability and change
- D4.3Climate change
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