Biology past papers 2002 1 List an external feature of each of the following types of organism that would identify the Group to which it belongs. type of organism| identifying feature| arachnid| | bird| | insect| | dicotyledonousplant| | 1 You are provided with a mixture of yeast and sucrose solution in a small container, labelled ‘yeast and sucrose solution’. You are also provided with a short length of Visking tubing tied at one end (knot 1).
This has already been soaked in water. Pour sufficient of the yeast and sucrose solution to almost fill the Visking tubing and tie the open end tightly with thread (knot 2). • Observe the volume and the appearance of the tube. • Wash the outside of the Visking tubing under running water.
• Place the Visking tubing in a boiling tube and then fill the boiling tube with limewater to just below knot 2, as shown in Fig. 1. 1. (a) (i) State the colour of the limewater that you poured into the boiling tube. Leave the experiment for at least 20 minutes and go on to Question 2.
After 20 minutes Gently move the Visking tube up and down in the boiling tube three times. (ii) State the colour of the limewater. ..
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... [1] • Examine carefully the Visking tube.
(b) State any change in volume observed. ....
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..... [1] • Transfer the Visking tube to a small beaker and cut a hole in the tube so that the ontents are released into the beaker.
(c) Describe the appearance and smell of the contents. appearance .....
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........................................................................................................................... smell ................................................................................................................................. ..................................................................................................................................... [2] (d) Describe the reactions that have taken place in the Visking tube. .......................................................................................................................................... .......................................................................................................................................... ......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... ......................................................................................................................................... ...................................................................................................................................... [5] (e) A student tested the limewater remaining in the boiling tube after the experiment for reducing sugar and protein. (i) Complete Table 1. 1. (ii) Explain how sucrose was converted into reducing sugar in the Visking
