Biology 5090/32 — May/June 2014
Cambridge O-Level · Practical Test · worked solutions for every part, with the mark scheme
Topics Experimental Contexts · Microscopy and Biological Drawing · Planning Experiments and Investigations · Observations and Measurements · Use of Techniques, Apparatus and Materials · Analysis, Conclusions and Evaluation
You are going to investigate the effect of sugar solution on onions.
You are provided with a transverse slice, thick, that was cut from a whole onion.
- Separate the outer ring from the others as shown in Fig. 1.1A.
- Cut this ring into two equal halves as shown in Fig. 1.1B.
- Place one piece in the dish containing distilled water and place the other piece in the dish containing sugar solution.
Draw the shape of these two pieces, at the start, in Table 1.1.
Show the position of the outer layer of onion on the drawing of each piece.
Table 1.1
| Shape of the piece | ||
|---|---|---|
| In distilled water | In sugar solution | |
| At start | ||
| After 30 minutes |
After 30 minutes or more observe the two pieces of onion.
Draw the shape of these two pieces in Table 1.1 in the lower spaces.
Describe the change in the shape in the two pieces of onion after 30 minutes compared to the pieces at the start.
______
Explain what has happened to cause the changes in the pieces of onion.
______
State one factor that was kept the same in this investigation and explain why it was kept the same.
______
The rest of this paper
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