This fully-resourced lesson describes the roles of enzymes in catalysing both intracellular and extracellular reactions and the mechanism of enzyme action. The engaging PowerPoint and accompanying resources have been designed to cover points 2.1.4 (a, b & c) of the OCR A-level Biology A specification and includes descriptions of Fischer’s lock and key hypothesis and Koshland’s induced-fit model as well as a focus on catalase and the digestive enzymes as intracellular and extracellular enzymes respectively.
The lesson has been specifically planned to tie in with module 2.1.2 where protein structure and globular proteins were covered. This prior knowledge is tested through a series of exam-style questions along with current understanding and mark schemes are included in the PowerPoint so that students can assess their answers.
Students will learn that enzymes are large globular proteins which contain an active site that consists of a small number of amino acids. Emil Fischer’s lock and key hypothesis is introduced to enable students to recognise that their specificity is the result of an active site that is complementary in shape to a single type of substrate. Time is taken to discuss key details such as the control of the shape of the active site by the tertiary structure of the protein. The induced-fit model is described so students can understand how the enzyme-susbtrate complex is stabilised and then students are challenged to order the sequence of events in an enzyme-controlled reaction.
The final part of the lesson focuses on intracellular and extracellular enzymes. The students are challenged on their recall of the roles of DNA helicase and polymerase in DNA replication before they are challenged on their ability to apply their knowledge and understanding to an unfamiliar situation with questions about catalase and its role in the decomposition of hydrogen peroxide. The lesson concludes with one further set of exam-style questions that challenge their knowledge of carbohydrates, lipids and proteins from module 2.1.3 as they have to recognise some extracellular digestive enzymes from descriptions of their substrates.
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As usual GJHeducation produces wonderfully interactive and engaging resources. Thank you for sharing.
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