Complete the sentences about enzymes by writing a suitable word or phrase in each of the spaces provided. Enzymes are involved in chemical digestion which produces small molecules that can be absorbed into the blood. Two examples of protease enzymes are pepsin and trypsin. Pepsin is produced by the and requires acidic conditions. These conditions are created by the release of which provides the optimum $$$\mathrm{pH}$$$ for pepsin activity and also kills harmful The produces trypsin which breaks down protein in $$$\mathrm{pH}$$$ conditions. These conditions are created by a substance called , which neutralises the gastric juices and also has an important role in the of fats and oils.

Biology

IGCSE&ALevel

CAIE

Exam No：0610_s23_qp_42 Year：2023 Question No：7

Answer:

Knowledge points:

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

7.4.1 State the significance of chemical digestion in the alimentary canal in producing small, soluble molecules that can be absorbed

7.4.10 Outline the role of bile in neutralising the acidic mixture of food and gastric juices entering the duodenum from the stomach, to provide a suitable pH for enzyme action

7.4.11 Outline the role of bile in emulsifying fats to increase the surface area for the chemical digestion of fat to fatty acids and glycerol by lipase

7.4.2 State the functions of enzymes as follows: – amylase breaks down starch to simpler sugars – protease breaks down protein to amino acids – lipase breaks down fats to fatty acids and glycerol

7.4.3 State where, in the alimentary canal, amylase, protease and lipase are secreted

7.4.4 State the functions of the hydrochloric acid in gastric juice, limited to killing bacteria in food and giving an acid pH for enzymes

7.4.5 State the functions of the hydrochloric acid in gastric juice, limited to killing bacteria in food and giving an acid pH for enzymes

7.4.6 State the functions of the hydrochloric acid in gastric juice, limited to killing bacteria in food and giving an acid pH for enzymes

7.4.7 Describe the digestion of starch in the alimentary canal: – amylase is secreted into the alimentary canal and breaks down starch to maltose – maltose is broken down by maltase to glucose on the membranes of the epithelium lining the small intestine

7.4.8 Describe pepsin and trypsin as two protease enzymes that function in different parts of the alimentary canal: – pepsin in the stomach – trypsin in the small intestine

7.4.9 Explain the functions of the hydrochloric acid in gastric juice, limited to the low pH: – denaturing enzymes in harmful microorganisms in food – giving the optimum pH for pepsin activity

Answer:

Knowledge points:

Solution:

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