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Warm Up Set up your journal for Cornell Notes and title it: Biochemistry- Enzymes Answer #1 and 2.
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Warm Up Take out Cornell Notes 1-8 and Foldable Answer the following:
Describe the affect on an enzyme if it is placed in a solution who’s pH is not the optimal pH for the enzyme. What is the relationship between sucrose and sucrose? Which is the enzyme and which is the substrate? Contrast the 2 types of inhibition.
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Warm Up Set up Cornell Notes for 4-8 Get out tickets for Auction
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What are enzymes?
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ENZYMES ARE A SPECIAL TYPE OF PROTEIN!
Enzymes are Biological catalysts that increase the rate of metabolic reactions.
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What is a catalyst?
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Catalyst- A substance that speeds up the rate of a reaction without being changed or used up during it. (they are reusable)
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What is the morphology (shape) of an enzyme?
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FOR PROTEINS: SHAPE MATTERS!
Proteins fold & twist into 3-D shape that’s what happens in the cell! Different shapes = different jobs growth hormone hemoglobin pepsin collagen
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PROTEIN STRUCTURES The four protein structures are: Primary
Describes the unique order of the amino acids joined together to make the protein Secondary Refers to the coiling and folding of a polypeptide chain that gives the protein its 3-D shape Examples: alpha (α) helix and beta (β) pleated sheet Tertiary Comprehensive 3-D structure of the polypeptide Quaternary Refers to the structure of a protein macromolecule formed by interactions between multiple polypeptide chains
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PROTEIN STRUCTURES
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Each enzyme has an active site which is the part of the molecule that a substrate binds to.
A substrate is a reactant that binds to the active site of an enzyme
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Enzyme
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How does the substrate bind?
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The active site of an enzyme is specific to its substrate
The active site is typically a pocket or groove on the surface of the protein.
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Substrate Enzyme Active Site Enzyme Enzyme – Substrate Complex
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A different enzyme is needed for almost every chemical reaction in your body.
A single enzyme can catalyze thousands or more reactions a second.
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Enzymes are responsible for metabolism (sum of all chemical reactions in the body).
Anabolic reactions- build-up (synthesize) molecules and require energy. (Dehydration Synthesis) Catabolic reactions- break-down (lyse) and release energy. (Hydrolysis)
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Examples of Enzymes: Remember, enzymes usually end in -ase.
Each enzyme is the specific helper to a specific reaction
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Lipase: breaks down lipids
Catalase: breaks Hydrogen Peroxide down into water and oxygen. Protease: breaks down proteins. Sucrase: breaks down sucrose. Amylase: in human saliva, breaks down starch (amylose). DNA polymerase builds DNA
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How do enzymes work?
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Most reactions in a cell require very high temperatures to get going, which would denature (kill) the cell.
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The energy needed to start a chemical reaction is called the activation energy.
Enzymes lower the activation energy needed for a reaction to begin. Enzymes are specific & unique to only one reaction.
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What affects an enzyme?
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IT’S SHAPE THAT MATTERS!
Proteins do their jobs, because of their shape Unfolding a protein destroys its shape wrong shape = can’t do its job unfolding proteins = “denature” unfolded “denatured” In Biology, it’s not the size, it’s the SHAPE that matters! folded
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Enzymes can be affected by the following:
Temperature Substrate Concentration pH
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Temperature Effects: If an enzyme is not at its optimal (best) temperature, it will become denatured. Human enzymes have an optimal temperature of around 37 degrees C.
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EFFECT OF TEMPERATURE ON ENZYME ACTIVITY
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Substrate Concentration Effects:
When all enzymes have their active sites filled with substrates, it’s called enzyme saturation. At this point, the reaction rate stays constant until more enzymes are added Use Bus Analogy: there are only so many seats in a bus… once all seats are taken, the bus is saturated with kids. At this point, no more students can get in until more seats (enzymes) are added.
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THE EFFECT OF SUBSTRATE CONCENTRATION ON ENZYME ACTIVITY
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pH Effects: Changes in pH changes the protein’s shape (denatures it)
Most human enzymes = pH 6-8 The enzyme pepsin in the stomach is most active in acidic environments ranging from a pH of
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EFFECT OF PH ON ENZYME ACTIVITY
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Inhibition Enzyme inhibitors are molecules that interact in some way with an enzyme to prevent it from working in the normal manner. Ex. poisons and drugs The 2 types of inhibitors are: 1. Competitive 2. Non-competitive Use Bus Analogy: there are only so many seats in a bus… once all seats are taken, the bus is saturated with kids. At this point, no more students can get in until more seats (enzymes) are added.
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Competitive Inhibitors
Use Bus Analogy: there are only so many seats in a bus… once all seats are taken, the bus is saturated with kids. At this point, no more students can get in until more seats (enzymes) are added.
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Non-Competitive Inhibitors
Use Bus Analogy: there are only so many seats in a bus… once all seats are taken, the bus is saturated with kids. At this point, no more students can get in until more seats (enzymes) are added.
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