2M ENZYMES 12pm

Question 1

Urease is an example of an oxidoreductase enzyme.

Answer 1

False

Question 2

Pyruvate carboxylase is an example of a ligase enzyme.

Answer 2

True

Question 3

The B vitamins are examples of
A) water-soluble vitamins.
B) essential amino acids.
C) essential minerals.
D) oil soluble vitamins.
E) vitamins that are stored in the liver.

Answer 3

A

Question 4

Enzyme cofactors are always metal ions, such as Zn2+ and Fe3+.

Answer 4

False

Question 5

Alanine transaminase is an example of a transferase enzyme.

Answer 5

True

Question 6

Which of the following is NOT a step in the enzyme-catalyzed conversion of a substrate to
product?
A) The substrate changes its shape so it can bind at the active site.
B) The substrate binds in the active site to form the E-S complex.
C) The enzyme assists in the conversion of the substrate to product.
D) The product is released from the active site.
E) A new substrate molecule binds to the enzyme for a new cycle

Answer 6

B

Question 7

Enzymes always require a cofactor.

Answer 7

False

Question 8

The function of the enzyme substrate complex is to provide an alternative reaction pathway
that
A) lowers the energy of the products.
B) lowers the energy of the substrate.
C) changes the concentration of the substrate.
D) decreases the activation energy for the reaction.
E) changes the possible product formed.

Answer 8

D

Question 9

Urea is converted to ammonia and carbon dioxide by the action of urease. What will be the
effect on the rate if the temperature of the reaction is lowered from 37 C (the optimum
temperature) to 27 ℃?

NH2 - C-NH2 + H20 —> 2NH3 + CO2
A) There will be no effect.
B) The rate will slow down.
C) The rate will double.
D) The rate will triple.
E) The rate will allow down, then speed up again.

Answer 9

B

Question 10

Most enzymes are
A) fluid-mosaic proteins.
B) induced proteins.
C) substrate proteins
D) fibrous proteins.
E) globular proteins.

Answer 10

E

Question 11

To what main class of enzymes does the enzyme that catalyzes the conversion of lactose to galactose and glucose belong?
A) oxidoreductase
B) transferase
C) hydrolase
D) lyase
E) isomerase

Answer 11

C

Question 12

Creatine kinase can be used in the diagnosis of
A) hepatitis.
B) rickets.
C) heart attack.
D) prostatitis.
E) cancer.

Answer 12

C

Question 13

The names of many enzymes can be recognized by the suffix __________
A) -ate
B) -ite
C) -ose
D) -ine
E) -ase

Answer 13

E

Question 14

To what main class of enzymes does the enzyme that catalyzes the following reaction belong?
CH3CCOO- —> CH3CHCOO-

Answer 14

Oxidoreductases

Question 15

Urease catalyzes only the hydrolysis of urea, and no other substrates. This limited activity is
called
A) absolute specificity.
B) extreme specificity.
C) rigid specificity.
D) noncompetitive specificity.
E) hyperspecificity.

Answer 15

A

Question 16

An enzyme that converts a cis double bond to a trans double bond is classified as a(n) _________

Answer 16

isomerase

Question 17

The active site of an enzyme
A) is remote from the site of substrate attachment.
B) is converted to a product.
C) catalyzes the reaction.
D) increases the energy of reaction.
E) includes the entire enzyme.

Answer 17

C

Question 18

To what main class of enzymes does the enzyme that catalyzes the following reaction
belong?
ser-ala —> ser + ala
A) oxidoreductase
B) transferase
C) hydrolase
D) lyase
E) isomerase

Answer 18

C

Question 19

How many generalized steps are there in the reaction of an enzyme (E) with a substrate (S) to form and release the product (P)?
A) one
B) two
C) three
D) four
E) five

Answer 19

B

Question 20

The purpose of the many chemical reactions in our bodies is to
A) store chemical energy in the body for future use.
B) produce the essential amino acids.
C) produce the essential lipids
D) release chemical energy for the production of macromolecules.
E) All of the above

Answer 20

D

Question 21

The optimum pH for the activity of pepsin is about

Answer 21

7.4

Question 22

Penicillin functions as an antibiotic by
A) potsoning bacteria with toxins.
B) raising the temperature of a bactertum.
C) bonding to metal ions in bacterial electron transport systems.
D) inhibiting the enzymes for cell wall formation in bacteria.
E) acting as an acetylcholinesterase inhibitor.

Answer 22

D

Question 23

The enzymes that extract energy from biamolecules for our use are located in the
A) plasma
B) cell mitochondria.
C) lymph
D) urine.
E) lipoproteins.

Answer 23

B

Question 24

Metal ions such as Zn2+ and Fe3+ are often needed by enzymes as
A) isozymes.
B) allosteres.
C) inhibitors.
D) cofactors.
E) substrates.

Answer 24

D

Question 25

The full name of the enzyme LDH is

Answer 25

lactate dehydrogenase

Question 26

In the induced-fit model of enzyme action, the enzyme active site
A) stays the same shape during substrate binding.
B) adjusts shape to adapt to the shape of the substrate.
C) stays the same shape while caustng a change in the shape of the substrate.
D) uses an inhibitor to adjust its shape for the substrate.
E) uses a cofactor to change the shape of a substrate.

Answer 26

B

Question 27

Penicillin-resistant bacteria can survive treatment with penicillin because they produce the enzyme

Answer 27

Penicillinase

Question 28

The general function of an enzyme in the body is to
A) catalyze chemical reactions.
B) maintain a neutzal pH.
C) act as a reactant in carbohydrate storage.
D) maintain homeostasis.
E) eliminate waste products from the blood.

Answer 28

A

Question 29

In any reaction catalyzed by an enzyme, the reacting molecule is called the
A) substrate
B) cofactor.
C) coenzyme.
D) isozyme.
E) allostere.

Answer 29

A

Question 30

Compared to an uncatalyzed reaction, an enzyme-catalyzed reaction

Answer 30

occurs at a faster rate