Unit 7 Quiz

Question 1

Enzymes

Answer 1

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.

Question 2

Enzymes structure

Answer 2

1. apo-enzyme- protein

2. cofactors- metal ions (common cofactor- copper)

Question 3

enzyme

Answer 3

lactase

Question 4

substrate

Answer 4

lactose

Question 5

product

Answer 5

glucose and galactose

Question 6

Factors that effect how well an enzyme will function

Answer 6

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

Question 7

optima

Answer 7

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

Question 8

range

Answer 8

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

Question 9

denatured

Answer 9

when a protein loses its structure and is unable to function

Question 10

EDTA

a chelator

Answer 10

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.

Question 11

Optima temperature

Answer 11

60 defrees

Question 12

Optima pH

Answer 12

pH 7

Question 13

activation energy

Answer 13

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

Question 14

substrate(s)

Answer 14

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

Question 15

active site

Answer 15

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.

Question 16

at extremely low temperatures,

Answer 16

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

Question 17

at extremely high temperatures,

Answer 17

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.

Question 18

enzymatic specificity

Answer 18

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.

Question 19

cofactors

Answer 19

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

Question 20

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

Answer 20

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

Question 21

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

Answer 21

enzyme: lactase
substrate: lactose

Question 22

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

Answer 22

Lactose (reactant) —–> glucose and galactose (products)

glucose can be used immediately to generate ATP

Question 23

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?

Answer 23

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

Question 24

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.

Answer 24

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

Question 25

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?

Answer 25

Maltose was the substrate.

Used to determine specificity (how specific is lactase for lactose)

Question 26

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

Answer 26

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