Biology 5090/62 — May/June 2011
Cambridge O-Level · Alternative to Practical · worked solutions for every part, with the mark scheme
Topics Experimental Contexts · Analysis, Conclusions and Evaluation · Planning Experiments and Investigations · Microscopy and Biological Drawing · Observations and Measurements
An investigation was carried out into how the green pigment is inherited in tobacco plants.
Two tobacco plants were cross-pollinated and the seeds were collected from the fruits that developed. These tobacco seeds were then placed at random on wet paper in two dishes and given suitable conditions for germination. Both dishes were exposed to light.
Fig. 1.1 shows the seedlings that developed.
Count the number of green seedlings and the number of white seedlings on the two dishes A and B and complete Table 1.1.
Table 1.1
| dish | number of seedlings: green | number of seedlings: white |
|---|---|---|
| A | ||
| B | ||
| total |
Suggest and explain what these total numbers in Table 1.1 indicate about the inheritance of the green pigment.
Suggest how you could improve the reliability of this investigation.
Suggest and explain which seedlings, given the right conditions, would be able to grow to become mature healthy plants.
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