AnswersBiology - SC3209 CRUnit Test

Catalysts Answers

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What is a substrate?

A
a molecule that acts as a catalyst
B
a place on the enzyme where the reaction occurs
C
a place on the product where the enzyme fits
D
a reactant that is catalyzed by an enzyme
2
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Which statement best describes the amount of catalyst that remains at the end of a reaction?

A
More catalyst is present at the end than at the beginning of the reaction.
B
Less catalyst is present at the end than at the beginning of the reaction.
C
The amount of catalyst is the same at the end as at the beginning of the reaction.
D
The catalyst is consumed by the reaction, so none remains at the end of the reaction.
3

Which component is released from the active site of an enzyme during a chemical reaction?

A
reactant
B
product
C
substrate
D
protein
4

Which statement best describes how a catalyst can speed up a chemical reaction?

A
The catalyst decreases the activation energy needed.
B
The catalyst increases the concentration of products.
C
The catalyst binds to enzymes to release substrates.
D
The catalyst increases the concentration of reactants.
5

A student wants to create a liquid volcano. The student observes bubbles in the soft drink prior to opening it. The student first proceeds to open the soft drink bottle and place it on the floor.Next the student drops candy tablets into the drink at a continuous pace. The student notices a very powerful reaction in which the candies, still intact, are pushed out of the soda as the drink fizzes and starts to bubble.In this scenario, what would be the catalyst?

A
The candy tablets being added to the drink.
B
The gasses being released when the drink was first opened.
C
The liquid in the container.
D
The container that holds the liquid.
6

Which term describes an enzyme?

A
substrate
B
reactant
C
catalyst
D
product
7

Which two substances bind using a lock-and-key mechanism?

A
enzyme and substrate
B
reactant and substrate
C
substrate and product
D
reactant and product
8

Photosynthesis is an example of

A
an exothermic reaction.
B
an endothermic reaction.
C
a reaction that gives off heat.
D
a reaction that emits energy.
9

How does a catalyst work?

A
by increasing the temperature of a chemical reaction
B
by decreasing the pressure of a chemical reaction
C
by increasing the concentration of reactants in a reaction
D
by decreasing the activation energy of a reaction
10

A substance that influences the reaction but does not participate in the reaction is a

A
catalyst
B
reactant
C
product
D
substrate
11

Lactase and carbonic anhydrase are examples of what type of substance?

A
substrate
B
reactant
C
product
D
enzyme
12

The lock-and-key mechanism refers to

A
the complementary shapes of an enzyme and a substrate.
B
the attractive forces between an enzyme and a substrate.
C
the ability of an enzyme to lower the activation energy of a reaction.
D
the ability of an enzyme to “unlock” the products of a reaction.
13

A researcher is designing a laboratory experiment to determine whether the inorganic substance A affects the rate of a reaction between two colored liquids, X and Y. When the reaction is complete, the liquid is clear. The reaction between X and Y is similar to one used by manufacturers to produce certain chemicals in factories.Which method would best answer his question about reaction rate and what will he find out about substance A?

A
First, he should measure the final temperature of the liquid when X and Y react without substance A. Then, he should measure the final temperature when he adds substance A to X and Y. He will find out if substance A is a catalyst.
B
First, he should measure how long it takes for the liquid to become clear if X and Y are mixed together. Then, he should measure how long it takes if he also adds substance A to X and Y. He will find out if substance A is a catalyst.
C
First, he should measure the final temperature of the liquid when X and Y react without substance A. Then, he should measure the final temperature when he adds substance A to X and Y. He will find out if substance A is an enzyme.
D
First, he should measure how long it takes for the liquid to become clear if X and Y are mixed together. Then, he should measure how long it takes if he also adds substance A to X and Y. He will find out if substance A is an enzyme.

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