learning outcomes b11- analyse the roles of enzymes in biochemical reactions explain the following...
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Learning OutcomesB11- analyse the roles of enzymesin biochemical reactionsexplain the following terms: metabolism, enzyme, substrate, coenzyme, activation energyuse graphs to identify the role of enzymes in lowering the activation energy of a biochemical reactionexplain models of enzymatic action (e.g., induced fit)
What do you know about enzymes?Definition?Function?Some examples in the body?Type of molecule?Where are they made?
Thinking Question..What are some chemical reactions that occur in the human bodyTo break down substances?
To synthesize substances?
Metabolic PathwaysCellular metabolism consists of many different chemical reactionsReactions result in synthesis or breakdown of substancesMost reactions occur in several steps (metabolic pathways)
Each reaction is catalyzed by a different enzyme
A B C DE1E2E3
ENZYMESAre usually proteinsEach have a specific shapeAre specific for one reactionAct as organic catalystsAre not used up in the reaction
SUBSTRATESAre the reactants in enzyme-catalyzed reactionsMay be broken down (ex. hydrolysis), or combine with other substrates (synthesis)Are used up in the reaction to produce products
What are some examples of substratesOf digestive enzymes?Of the enzyme DNA polymerase?Of enzymes in the mitochondria?Of hydrolytic enzymes in the lysosomes?
Examples of enzymesPolymerases - catalyze polymerization reactionsCatalase - breaks down hydrogen peroxide (H2O2)Digestive enzymes - amylase, lipase, lactase, etc. (names usually end in ase)
Enzyme activityAll chemical reactions have a specific energy of activation, needed to get the reaction startedEnzymes lower the energy of activation of a chemical reaction, allowing the reaction to take place with a lower input of energy (at body temperature)
Enzymes are specific for a particular substrate due to their shape
Lock and key modelThe active site of an enzyme binds to the substrate like a lock-and-key An enzyme - substrate complex is formed
Induced fit modelSometimes the active site of an enzyme may change shape to fit the substrate
The reaction occurs while the substrate is attached to the enzymeAfter the reaction is complete, the products are releasedThe enzyme is now free to combine with another molecule of substrate
*Need clay, lego blocks to model synthesis, hydrolysis, induced fit***********