ENZYMES AND THEIR ROLE IN METABOLISM AP Big Ideas: #2, #3
ENANTIOMERS CHECK
Introduction to Metabolism Enzymes: Speed up metabolic reactions by lowering activation energy How might the structure of an enzyme lower activation energy?
Enzymes lower activation energy (E A )
How do enzymes work? Active Site Lock and KeyInduced Fit
Role of Temperature? Why are enzyme-catalyzed reactions temperature dependent? –Low temperatures
Types of Metabolic Reactions Catabolism –Breaking down starch Anabolism –Building muscles
Free Energy: Overall energy change in the reaction Key Point: Addition of enzymes do not affect free energy! Why are some reactions not possible without enzymes?
Biological Energy=ATP Modified nucleotide Energy held in the bonds between phosphate molecules. ATP can activate enzymes.
Role of ATP
Regulation of Enzyme Activity What conditions affect the rate of enzyme reactions? Answer the graphing exercise to determine factors that affect enzymes!
Summary pH –Acids –Bases Temperature –High –Lower
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What does it mean to denature? Secondary and Tertiary structure of a protein becomes destroyed. Permanent! What level of protein structure is not affected by dentaturation?
Toothpickase Model Present your question: What was your hypothesis How did you model your IV? Show us your graph and identify the effect of your variable on v-max Analyze your trend and discuss why you saw your results!
Concentration Increase concentration of substrate –What happens over time? Increase concentration of enzyme –What happens over time?
Visualization
Review: What is Vmax? All enzyme active sites are bound to enzyme.
Other factors affecting enzymes Activators –Cofactors –Coenzymes Inhibitors –Competitive –Allosteric
Cofactors ATP can phosphorylate an enzyme and change it to an active conformation.
Coenzymes Coenzyme q10 activates enzymes in the electron transport chain of the mitochond.
Inhibition of Enzymes Competitive: two substrates compete for the active site
Competitive Inhibition Methanol-->formaldehyde & formic acid (deadly!) Reaction is enzyme catalyzed *How might ethanol treat wood alcohol poisoning?
Inhibition of Enzymes Allosteric: Occurs when a material binds at another site and changes the shape of the protein rendering it nonfunctional
Allosteric Inhibition Mad Hatter Ag+, Hg2+, Pb2+ have an affinity for -SH groups Acts as a reducing agent
Enzyme Lab We will design a standard curve to “assay” the concentration of the enzyme catalase in two samples. What is a standard curve? Read the glucose standard curve model lab and find out!