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Flashcards in Unit 7 Quiz Deck (26)


a protein that speeds up chemical reactions. It also lowers the amount of activation energy.

-a protein that acts as a catalyst, lowering the activation energy needed for reactions to progress in cells. The reaction can still occur without the presence of the enzyme, but at a much slower rate.


Enzymes structure

1. apo-enzyme- protein
2. cofactors- metal ions (common cofactor- copper)









glucose and galactose


Factors that effect how well an enzyme will function

1. specificity
2. Cofactor necessity
3. Temperature
4. pH



one temperature and one pH value at which an enzyme will produce the most product and work the best at



temperature and pH values range that an enzyme can still function at



when a protein loses its structure and is unable to function



(a chelator)

strips cofactors (ions) from the active site.

(therefore, the presence of EDTA should remove any effect that these ions would have on the effectiveness of lactase in lowering the activation energy needed for lactose metabolism.


Optima temperature

60 defrees


Optima pH

pH 7


activation energy

the minimum amount of energy needed for a chemical reaction to occur, yielding products from a given set of reactants



the reactant(s) of the reaction that is/are bound by the enzyme


active site

a region of the enzyme where binding to substrate occurs. This site is flexible, and can reform to assit with the catalysis of the reaction of the substrates. Once the substrates have formed product(s) and have become unbound, the active site can return to its original shape.


at extremely low temperatures,

molecules move so slowly that reaction rates can be hampered even though the enzyme is still properly folded and active.


at extremely high temperatures,

bonds and interactions that exist between the amino acid side chains (R groups) in an enzyme become disrupted. The result is that the enzyme is incapable of maintaining its shape, and therefore unfolds, becoming inactive. This process of forcing a protein to lose its structure, and in most cases its functionality, is called protein denaturation.


enzymatic specificity

The active site or active sites of every enzyme are composed of a particular array of amino acids, and, therefore, amino acid side chains. These amino acid side chains form chemical interactions with the substrate of the enzyme. Furthermore, the active site exhibits specificity for the substrate of the enzyme. This means that in theory, the enzyme should bind and catalyze the reaction for its specific substrate(s) better than with any other substrates.



are non-protein molecules or ions that bind to proteins (usually enzymes).


What is an enzyme? what is its role, and how does it perform this role?

molecule that catalyzes a chemical reaction. Binds substrate(s) to its active site and decreases energy of activation needed for reaction to occur


What was the name of the enzyme that we used, and what was the name of its particular substrate?

enzyme: lactase
substrate: lactose


When the substrate was metabolized, what produces were formed? Which of these products could immediately be used to create energy?

Lactose (reactant) -----> glucose and galactose (products)

glucose can be used immediately to generate ATP


Based off of your results, if i were to ask you to create a scenario that used the enzyme from lab to create a large quantity of products, please describe the conditions in which you would set up your experiment. Why would you select these particular conditions?

would select optimum temperature and pH. Conditions that are denoted as "optimum" are those where enzyme functions best.


Looking at the graph in number 5, you will notice the amount of product produced at 0 C and at 100 C are the same. Please elaborate as to the reason or reasons that we did not observe enzymatic activity in each of these scenarios.

0 degrees C: Too cold, not enough kinetic energy; enzyme properly folded, but reaction occurs slowly

100 degrees C: Too hot, the enzyme denatures. It is not folded/functional, and cannot speed up the reaction


In one of the experiments, you added a substrate that looked similar to the original substrate. What was this substrate analog, and what was the purpose of the experiment in which it was used?

Maltose was the substrate.
Used to determine specificity (how specific is lactase for lactose)


EDTA was used in the final experiment of the lab. Given the results below, please interpret this data, and describe what it means in terms of enzymatic activity.

--Control (mg/ml of product): 1000
--EDTA (mg/ml of product): 250

Enzyme requires metal ions (they act as cofactors) for its activity