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How do enzymes work Biology Extraclasscom
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How do enzymes work? • Enzymes are nothing but catalysts of biochemical reactions. • They are protein molecules present in cells that speed up chemical reactions in the body but do not get used up in the process. • Do you know how an enzyme works? • In this video, we will discuss the different models for enzyme action and its types. • There are two different theories proposed for enzyme action • i) Lock and key model and • ii) Induced fit model • The first theory, Lock and key model was proposed by Emil Fischer in 1894. • In this model, the lock is an enzyme and the key is the substrate. • Only A correctly sized key that is, the substrate fits into the keyhole, that is, an Active site of the lock that is an enzyme. • This model explains enzyme specificity but, It fails to explain the stabilization of the transition state that enzyme achieves. • The second theory, Induced fit model, was proposed by Daniel Koshland in 1958. • According to Daniel, enzymes are flexible structures. • When the active site on the enzyme makes contact with a proper substrate, the enzyme molds itself to the shape of the molecule. • Enzymes are of different types, some rearrange the atoms, while some join two chemical compounds together. • The enzymes are classified according to the reaction they catalyze. • The first class of enzyme is Oxidoreductase which adds or removes the hydrogen atoms in a chemical reaction • The second class is Transferase, as the name suggests, this enzyme transfers the groups or atoms between donor and acceptor molecules. • The third class is Hydrolase, the enzyme participates in a hydrolysis reaction by adding water across a bond. • The fourth class is Lyases, the enzyme forms double bonds by removing groups from a substrate other than by hydrolysis or that adds groups to double bonds. • The fifth class of enzyme are Isomerase, these enzymes create isomers by rearranging the atoms in a biochemical reaction. • The sixth class of enzyme is Ligase, which joins the two chemical groups together, with the use of energy that is, ATP molecule. • Let’s answer a few questions asked in the medical entrance exam. • Question- Who proposed the lock and key model for enzyme action - • (1)Emil Fischer • (2)Koshland • (3)Watson and Crick • (4)Waldeyer • This question was asked in Punjab PMT 2011. • Solution- The Lock and key model, was proposed by Emil Fischer in 1894. In this model, the lock is an enzyme and the key is the substrate. • Hence, option (1) is the correct answer. • Question-2 Which class of enzyme performs hydrolysis - • (1)Transferase • (2)Oxidoreductase • (3)Hydrolase • (4)Isomerase • This question was asked in MP PMT 2012 • Solution - Hydrolase, the enzyme participates in a hydrolysis reaction by adding water across a bond. • Hence option (3) is correct. • This concludes our video on theories and classes of different enzymes. • • Download Extra class app: - • Play Store: http://bit.ly/extraclassapp • Follow us on our social media handles to stay updated. • Website – https://www.extraclass.com/ • Facebook - / extraclassofficial • Instagram - / extraclassofficial • Youtube - / extraclass • Twitter - / extraclass_com • Happy Learning!! • “Thanks for watching”. • #Extraclass • #Enzymeswork • #biology • #science • #class10 • #class11 • #cbse • #icse • #neet • #aiims
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