2022年医学专题—Stem-cells：干细胞(1).ppt

Enzymes,All chemical reactions convert reactants to products.Ex.2 HCl+Mg MgCl2+H2Enzymes are a class of protein.The job of an enzyme is to catalyze a reaction(help it get started).,第一页，共十六页。,第二页，共十六页。,第三页，共十六页。,第四页，共十六页。,第五页，共十六页。,第六页，共十六页。,Enzymes lower the amount of energy needed to get the reaction going activation energy.,第七页，共十六页。,Examples,DNA polymerase makes DNARennin curdles milk proteinLipase breaks down fatsProtease breaks down proteinsUsually end with“-ase”,第八页，共十六页。,How do enzymes work?,The material that an enzyme works on is called a substrate.,Enzymes work like a lock and key must have right enzyme for each substrate.,第九页，共十六页。,How do enzymes work?,The active site on the enzyme is what binds to the substrate.Why enzymes?Specificness and Reusing enzymes,第十页，共十六页。,Enzyme Shape,The shape of each protein is determined by the sequence of amino acids used to make that protein.Just as for proteins,shape is extremely important.If proteins/enzymes dont have the correct temperature,pH,or salt concentration,they will lose their shape or denature and not be able to function.Denaturing,第十一页，共十六页。,第十二页，共十六页。,第十三页，共十六页。,Tutorial activity,第十四页，共十六页。,Competitive Inhibition,In a process called competitive inhibition,molecules that fit the active site can prevent the enzyme from working.,第十五页，共十六页。,内容(nirng)总结,Enzymes。Usually end with“-ase”。http:/www.lewport.wnyric.org/jwanamaker/animations/Enzyme%20activity.html。Competitive Inhibition,第十六页，共十六页。,