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26 Cards in this Set
- Front
- Back
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What is the purpose of enzymes?
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They are proteins that act as catalysts in our cells, making reactions in cells go at a speed necessary to maintain life.
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What happens to enzymes after they are used?
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They typically remain unchanged and are reused again.
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What are catalysts?
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Substances that increase the rate of a chemical reaction; many enzymes act as catalysts.
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What are some factors that affect enzyme activity?
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pH, temperature, presence of inhibitors, substrate concentration, cofactor activity
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What is the purpose of sucrase?
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Sucrase hydrolyzes sucrose to form glucose and fructose. It is a necessary enzyme in the human body.
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What is the substrate in an enzymatic reaction?
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A substrate is the molecule that is acted upon and changed by the enzyme
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True or False: Enzymes are interchangeable and certain enzymes can be used on multiple substrates.
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False. Enzymes are specific for the substrate they act upon. Example: Sucrase acts on sucrose.
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What is the reaction that represents sucrose being split (hydrolyzed)?
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Sucrose (substrate) + Sucrase (enzyme) -----> glucose + fructose (monomers / monosaccharides)
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What are the properties of catechol?
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It is colorless, and is oxidized (electrons removed from) in response to injury to a plant in which the inside of the plant is exposed to air. Small amounts of catechol exist beneath the surface of many plants.
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What is the purpose of catecholase?
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It is an enzyme that participates in response to injury in plants; catalyzes the conversion of catechol to benzoquinone.
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What is the chemical equation for the oxidation of catechol?
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Catechol + 1/2O2 + catecholase (enzyme) -----> benzoquinone + H2O
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What color is benzoquinone?
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reddish-brown
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What is the purpose of benzoquinone?
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It acts as an antiseptic for the plant, deterring pathogens that can enter the damaged tissue.
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Where can we observe this process in everyday life?
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Eating an apple, pear, etc.
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What color is a 540nm wavelength of light?
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Green.
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Why is a 540nm wavelength of light selected for use by the spectrophotometer?
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-->Colors seen by your eye are actually the wavelength of light reflected by an object. Green will not be seen since it is being reflected by the pigment on the potato.
--> Since green is not a color seen with the conversion of catechol to benzoquinone, the green wavelength of light is absorbed by benzoquinone and not reflected. --> Green light will be absorbed by the benzoquinone which the spectrophotometer can measure in change in absorbance. |
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What color is reflected by benzoquinone?
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Orange wavelength.
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Does catechol absorb green light?
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No.
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An increase in the concentration of benzoquinone would do what to the solution?
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Turn it orange.
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The amount of green light absorbed by the solution will ___________ over time if ___________ catalyzes the conversion of catechol to benzoquinone.
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Increase; catecholase
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What is the purpose of a cofactor?
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Many enzymes require cofactors to achieve active conformation (proper shape)
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What would happen to an enzyme in the absence of a cofactor?
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an enzyme's active site will not bind the substrates(s) and catalyze the reaction.
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What are chelating agents?
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Chelating agents are a group of compounds that bind metallic ions and change the shape of the cofactor; they may also be used medicinally.
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What are two chelating agents?
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EDTA (ethylenediamine tetraacetic acid) and PTU (phentyl thiourea).
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What does EDTA bind?
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Calcium (Ca^2+) and Magnesium (Mg^2+) ions.
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What does PTU bind?
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Copper (Cu^2+).
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