Plants can make fats, starch and proteins. (i) State the names of the reagents that can be used to test samples of plant tissue for starch and protein. starch ............................................................................................................................. protein ............................................................................................................................ (ii) Describe the method you would use to test a sample of plant tissue for fat. ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . .................................................................................................................................

Biology

IGCSE&ALevel

CAIE

Exam No：0610_s24_qp_51 Year：2024 Question No：3(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)

5.1.1 Define the term catalyst as a substance that increases the rate of a chemical reaction and is not changed by the reaction

5.1.10 Explain the effect of changes in temperature on enzyme activity in terms of kinetic energy, shape and fit, frequency of effective collisions and denaturation

5.1.11 Explain the effect of changes in pH on enzyme activity in terms of shape and fit and denaturation

5.1.2 Define enzymes as proteins that function as biological catalysts

5.1.3 Describe why enzymes are important in all living organisms in terms of reaction speed necessary to sustain life

5.1.4 Describe enzyme action with reference to the complementary shape of an enzyme and its substrate and the formation of a product (knowledge of the term active site is not required)

5.1.5 Investigate and describe the effect of changes in temperature and pH on enzyme activity

5.1.6 Investigate and describe the effect of changes in temperature and pH on enzyme activity

5.1.7 Investigate and describe the effect of changes in temperature and pH on enzyme activity

5.1.8 Explain enzyme action with reference to the active site, enzyme-substrate complex, substrate and product

5.1.9 Explain the specificity of enzymes in terms of the complementary shape and fit of the active site with the substrate

Answer:

Knowledge points:

Solution:

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