Samples of three different types of food were labelled $$$\mathbf{X}, \mathbf{Y}$$$ and $$$\mathbf{Z}$$$. The samples were tested for protein and starch. The food tests showed that: - Food $$$\mathbf{X}$$$ contained both protein and starch. - Food $$$\mathbf{Y}$$$ contained starch only. - Food $$$\mathbf{Z}$$$ contained protein only. Complete Table 3.2 to show the expected final colours of these food tests. Table 3.2 Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series.

Biology

IGCSE&ALevel

CAIE

Exam No：0610_w24_qp_61 Year：2024 Question No：3(e)

Answer:

Knowledge points:

4.1.1 List the chemical elements that make up: – carbohydrates – fats – proteins

4.1.10 Describe the roles of water as a solvent in organisms with respect to digestion, excretion and transport

4.1.2 State that large molecules are made from smaller molecules, limited to: – starch and glycogen from glucose – cellulose from glucose – proteins from amino acids – fats and oils from fatty acids and glycerol

4.1.3 Describe the use of: – iodine solution to test for starch – Benedict’s solution to test for reducing sugars – biuret test for proteins – ethanol emulsion test for fats and oils – DCPIP test for vitamin C

4.1.4 Describe the use of: – iodine solution to test for starch – Benedict’s solution to test for reducing sugars – biuret test for proteins – ethanol emulsion test for fats and oils – DCPIP test for vitamin C

4.1.5 Describe the use of: – iodine solution to test for starch – Benedict’s solution to test for reducing sugars – biuret test for proteins – ethanol emulsion test for fats and oils – DCPIP test for vitamin C

4.1.6 State that water is important as a solvent

4.1.7 Explain that different sequences of amino acids give different shapes to protein molecules

4.1.8 Relate the shape and structure of protein molecules to their function, limited to the active site of enzymes and the binding site of antibodies

4.1.9 Describe the structure of DNA as: – two strands coiled together to form a double helix – each strand contains chemicals called bases – cross-links between the strands are formed by pairs of bases – the bases always pair up in the same way: A with T, and C with G (full names are not required)

Answer:

Knowledge points:

Solution:

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