Catalase is an enzyme that catalyses the breakdown of hydrogen peroxide to form water and oxygen. A student investigated the activity of catalase in tissues from two different plants. The oxygen produced during the breakdown of hydrogen peroxide forms a foam. The height of the foam can be used as a measure of the activity of the catalase present in plant tissue. The student used this method: Step 1 Label one test-tube $$$\mathbf{P}$$$ and another test-tube $$$\mathbf{A}$$$. Step 2 Cut a cylinder of tissue from a potato and a cylinder of tissue from an apple. Step 3 Cut a potato cylinder into five equal pieces. Each piece should be approximately 4 mm in length, as shown in Fig. 1.1. Step 4 Put all five potato pieces into test-tube $$$\mathbf{P}$$$. Place the test-tube in a test-tube rack. Step 5 Repeat steps 3 and 4 using the apple cylinder and the test-tube labelled $$$\mathbf{A}$$$. Step 6 Use a syringe to put $$$15 \mathrm{~cm}^{3}$$$ of hydrogen peroxide solution into test-tube $$$\mathbf{P}$$$. Step 7 Start a stop-clock and wait for five minutes. Step 8 After five minutes, place a ruler against the outside of test-tube $$$\mathbf{P}$$$ and measure the maximum height of the foam. Step 9 Repeat steps 6 to 8 with test-tube $$$\mathbf{A}$$$ and the pieces of apple. Fig. 1.2 shows a diagram of test-tube $$$\mathbf{P}$$$ and test-tube $$$\mathbf{A}$$$ in step 8 and step 9 . Describe how you could test samples of potato and apple to determine if vitamin C is present. Give the result of a positive test. test ........................................................................................................................................ ............................................................................................................................................... . result ..................................................................................................................................... ............................................................................................................................................... .

Biology

IGCSE&ALevel

CAIE

Exam No：0610_s24_qp_63 Year：2024 Question No：1(b)

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:

Related Question