Lab Quiz #4 - Enzymes

Question 1

enzymes are biological __________

Answer 1

catalyst

Question 2

Most enzymes are _________

Answer 2

proteins (quaternary)

Question 3

What is the primary function of an enzyme?

Answer 3

to increase the rate of chemical reactions by lowering the energy (Ea) required for a reaction to proceed

Question 4

T/F: Enzymes are changed at the end of a reaction

Answer 4

false; enzymes shape remains the same at the end of a reaction

Question 5

T/F: Enzymes do not change the result of the reaction

Answer 5

true; enzymes only help speed up the reaction; they do not do anything to change the result/product

Question 6

Describe the process of an enzyme

Answer 6

1. substrate fits into active sites
2. enzyme substrate complex is formed
3. reaction occurs
4. products dissaociate
5. enzyme is unaltered

Question 7

What do most enzymes names end in?

Answer 7

“-ase”

Question 8

Which is NOT an enzyme?

maltase
sucrose
lipase
amylase

Answer 8

sucrose

Question 9

Compare the difference between a phosphatase and a kinase

Answer 9

phosphatases: remove phosphate group
kinases: add phosphate group

Question 10

How do you measure enzyme activity?

Answer 10

measure the rate in which substrate is converted to product

Question 11

What factors can influence enzyme activity?

Answer 11

temperature
pH

Question 12

What was the chemical reaction used in lab?

Answer 12

starch ——————–> glucose

enzyme = fungal amylase

Question 13

In lab, how were you able to tell if amylase was effective in digesting starch?

Answer 13

If amylase was effective in digesting starch, there would be a uniformity of all the wells (all clear/transparent).

This means that glucose was detected and amylase worked to break down starch.

Question 14

In lab, how were you able to tell if amylase was NOT effective in digesting starch?

Answer 14

If amylase was not effective in digesting starch, there would be wells that had black precipitate.

This means there was a detection of starch, meaning amylase did not work and did not break down the starch into glucose.

Question 15

What happened to amylase if there was only black precipitate in all the wells?

Answer 15

If there was only black precipiate in the wells, this means that the enzyme (amylase) got denatured.

Question 16

Enzymes have ________ temperature and ______ _______

Answer 16

optimal
pH ranges

Question 17

By looking at a graph that measures enzyme activity, how can you tell which temperature/pH is optimal/ideal?

Answer 17

the peak of the curve will be its optimal temperature because enzyme activity is the highest (substrate is converted to the product the fastest)

Question 18

In the lab, what was the optimal pH and temperature?

Answer 18

pH: 5
temperature: 40

Question 19

What was the indicator used in the experiment?

Answer 19

iodine

Question 20

What other processes in the body, besides digestion, are controlled by enzymes?

Answer 20

• cellular respiration
• removal of H+ from blood

Question 21

How were you able to identify the optimal temperaure/pH in your experiment?

Answer 21

look for plates that were uniformly light/clear in color (means presence of glucose detected and amylase worked)

Question 22

__________ environments will have _____________ optimal pH/temperature

Answer 22

different
different

Question 23

What would you expect to happen to the 0° and 100° tubes if you were to return them to room temperature and test for starch? Explain

Answer 23

0°: cold will decrease enzyme activity and will not denature enzyme, so some enzyme activity

100°: hot will denature enzymes and will not regain enzyme activity at room temperature