Deck 5: Enzymes, Coenzymes, and Energy

Question 1

Enzyme inhibition

A) refers to the interference with a chemical reaction caused by an enzyme.
B) is the tendency to stop a chemical reaction caused by two different enzymes interfering with each other.
C) is caused by a chemical that prevents the enzyme from acting on the natural substrate.
D) is the ability of an enzyme to decrease the need for activation energy.

Answer 1

is caused by a chemical that prevents the enzyme from acting on the natural substrate.

Question 2

The point on the enzyme where the enzyme causes the substrate to change is called the

A) attachment site.
B) active site.
C) binding site.
D) enzyme-substrate complex.

Answer 2

active site.

Question 3

A given enzyme works on

A) any number of different substrates.
B) one of two possible substrates.
C) no substrate.
D) one type of substrate.

Answer 3

one type of substrate.

Question 4

A type of molecule that helps certain enzymes function is a(n)

A) deactivator.
B) antibiotic.
C) vitamin.
D) All of these answers are true.

Question 5

The amount of energy needed to start two reactants to form a product is

A) reaction energy.
B) kinetic energy.
C) activation energy.
D) potential energy.

Question 6

The optimum condition for an enzyme

A) is 60 $\degree$ C.
B) is where it works best.
C) cannot be determined.
D) All of these answers are true.

Question 7

A molecule occupies the active site of an enzyme so that there can be no normal enzyme-substrate complex formed. This is called

A) enzyme completion.
B) denaturation.
C) enzyme inhibition.
D) enzyme specificity.

Question 8

As the concentration of an enzyme increases for a given substrate,

A) the reaction rate increases similarly.
B) the turnover number decreases at the same rate that the enzyme concentration increases.
C) the rate of the reaction decreases to a point.
D) there is no change in the reaction.

Question 9

An enzyme is also known as

A) an inorganic protein.
B) an organic catalyst.
C) a metal ion.
D) an inhibitor.

Question 10

When you boil egg white (albumin is protein) you have

A) inhibited the protein.
B) denatured the protein.
C) competed with the protein.
D) optimized the protein.

Question 11

Enzymes are

A) fats.
B) sugars.
C) starches.
D) proteins.

Question 12

Enzyme competition occurs when

A) one type of enzyme reacts with one type of substrate.
B) an enzyme does not react with a substrate.
C) three different types of enzymes react with one type of substrate.
D) an enzyme stops a reaction.

Question 13

It is FALSE that enzymes

A) are catalysts.
B) are proteins.
C) lower the activation energy of a reaction.
D) are used up in a reaction.

Question 14

The number of molecules with which an enzyme reacts is the

A) end product.
B) optimum.
C) substrate.
D) turnover number.

Question 15

An enzyme poison ____ enzyme function.

A) balances
B) prevents
C) helps
D) competes with

Question 16

An increase in enzyme or substrate concentration will

A) increase the amount of reaction.
B) decrease the amount of reaction.
C) not change the amount of product produced.
D) interfere with the reaction.

Question 17

The substrate is

A) the material changed by an enzyme.
B) a coenzyme.
C) the material formed by an enzyme.
D) always a protein.

Question 18

An enzyme is about the same as a(n)

A) catalyst.
B) inhibitor.
C) substrate.
D) end product.

Question 19

Denature means to permanently change a(n)

A) amino acid.
B) protein.
C) fat.
D) carbohydrate.

Question 20

Several enzymes that fit the same substrate are

A) the same as the substrate.
B) not able to function.
C) in competition for the same substrate.
D) able to interact and form one complex of enzymes.

Question 21

Every enzyme functions best at

A) high pH.
B) low pH.
C) optimum pH.
D) neutral pH.

Question 22

The reason why an enzyme fits a specific substrate is due to its

A) inhibitor.
B) three-dimensional shape.
C) acid side chain.
D) nuclear membrane.

Question 23

Using an enzyme in a chemical reaction will reduce the need for

A) a coenzyme.
B) an inhibitor.
C) activation energy.
D) end products.

Question 24

Which of the following is an example of an enzyme-substrate complex?

A) glucose
B) glucase
C) vitamin D
D) sucrose-sucrase

Question 25

The turnover number involves the rate of change in the

A) enzyme.
B) end product.
C) coenzyme.
D) substrate.

Question 26

A protein that increases the rate of a chemical reaction is

A) a substrate.
B) a coenzyme.
C) an enzyme.
D) an inhibitor.

Question 27

The material that is changed by the enzyme is the

A) coenzyme.
B) inhibitor.
C) catalyst.
D) substrate.

Question 28

An example of an enzyme is

A) maltose.
B) fructose.
C) hydrogen peroxide.
D) dehydrogenase.

Question 29

The active site is a part of the

A) enzyme.
B) inhibitor.
C) substrate.
D) end product.

Question 30

If lipase breaks lipids into fatty acids and glycerol, then lipase can

A) cause an additional breakdown of the fatty acid.
B) cause the formation of lipids.
C) work on amino acids.
D) denature proteins.

Question 31

The rate of an enzyme reaction is the

A) optimum number.
B) substrate number.
C) turnover number.
D) activation number.

Question 32

When a protein is denatured, the turnover number will

A) increase.
B) remain the same.
C) decrease.
D) change with the pH.

Question 33

An inhibitor will result in the production of

A) more product.
B) the same amount of product.
C) less product.
D) The answer depends upon the inhibitor.

Question 34

A method of controlling the synthesis rate of molecules is called

A) negative-feedback control.
B) tertiary control.
C) enzyme-inhibition control.
D) depression-feedback control.

Question 35

This mechanism is active when the end product of an enzyme-controlled biochemical pathway reaches a high enough concentration to interfere with one of the enzymes essential to the functioning of that pathway.

A) end-product control
B) negative-feedback control
C) negative by-product control
D) inhibition control

Question 36

Chemical messengers in the cell that control the amounts of enzyme produced is/are

A) DNA.
B) gene regulator proteins.
C) inhibitors.
D) coenzymes.

Question 37

As the amount of substrate is increased in an enzyme-substrate reaction,

A) the amount of enzyme also increases proportionally.
B) enzymes work faster.
C) the amount of product increases.
D) enzymes become denatured faster.

Question 38

To denature an enzyme is to

A) activate the enzyme.
B) change the protein structure of the enzyme.
C) increase the enzyme's turnover number.
D) attach the enzyme to the substrate.

Question 39

An inhibitor

A) denatures an enzyme.
B) attaches itself to the product, thereby preventing the product from functioning.
C) attaches itself to the enzyme, thereby preventing the enzyme from forming the enzyme-substrate complex.
D) renders the enzyme inactive by attaching positively charged hydrogen ions to the enzyme's side chains.

Question 40

You could increase the amount of product produced over a given amount of time in an enzyme-mediated reaction by

A) adding ice.
B) adding an inhibitor.
C) adding more enzyme.
D) boiling the enzyme.

Question 41

Acetyl can be a substrate for a number of different reactions involving different enzymes and resulting in different products. This situation can be described as

A) enzymatic inhibition.
B) negative-feedback inhibition.
C) substrate competition.
D) enzymatic competition.

Question 42

It is FALSE that

A) coenzymes are needed in many reactions to enable the enzyme to function as a catalyst.
B) water-soluble vitamins like thiamine, riboflavin, and niacin can be converted to coenzymes.
C) coenzymes are nonprotein molecules.
D) coenzymes remain unchanged during a reaction.

Question 43

Enzymatic competition results when

A) several substrates can combine with one enzyme.
B) one enzyme can bring about the formation of several substrates.
C) several types of enzymes can combine with a given substrate.
D) one enzyme can produce several types of products.

Question 44

An enzyme's name is NOT likely to include

A) the type of reaction the enzyme facilitates.
B) the location in the body where the enzyme is commonly found.
C) the substrate the enzyme works on.
D) -ase.

Question 45

The enzyme that facilitates a reaction adding a phosphate group to a three-carbon sugar while removing a hydrogen would most likely be named

A) triose phosphate dehydrogenase.
B) phosphoglyceromutase.
C) pyruvate kinase.
D) phosphofructokinase.

Question 46

The induced fit hypothesis states that

A) a single enzyme can adjust its shape to fit with several types of substrate.
B) a substrate will adjust its shape to fit the shape of the enzyme.
C) an enzyme can adjust itself to a substrate as they come together.
D) the enzyme and substrate have no set shape until they unite.

Question 47

An enzyme can

A) reduce the rate of a chemical reaction.
B) increase the rate of a chemical reaction as much as two times.
C) increase the rate of a chemical reaction as much as ten times.
D) increase the rate of a chemical reaction as much as several thousand times.

Question 48

Enzymes are most directly involved with

A) metabolic processes.
B) generative processes.
C) responsive processes.
D) control processes.

Question 49

The enzyme salivary amylase in the mouth breaks down starch into the simple sugar glucose. The mouth has a pH of 7. Salivary amylase will

A) also break down starch in the stomach, which has a pH of 2.
B) be able to break down proteins to amino acids in the stomach.
C) not be able to break down starch in a test tube. It needs to be in the mouth.
D) work at temperatures lower than body temperature (37 $\degree$ C).

Question 50

Enzyme inhibitors

A) slow enzyme-controlled reactions because the inhibitor prevents the substrate from attaching to the active site of the enzyme.
B) are used to speed up enzyme-controlled reactions by inhibiting molecules that get in the way of the enzyme.
C) are able to lower the temperature and slow down reactions.
D) lower the pH and stop enzyme-controlled reactions.

Question 51

The enzyme salivary amylase in the mouth breaks down starch into the simple sugar glucose. The mouth has a pH of 7. Salivary amylase will

A) also break down starch in the stomach, which has a pH of 2.
B) be able to break down proteins to amino acids in the stomach.
C) be able to break down starch in a test tube. It doesn't need to be in the mouth.
D) only work at body temperature.

Question 52

The pH of the solution in which an enzyme-controlled reaction takes place

A) is not important, since enzymes work well at a variety of pH levels.
B) is important, because changing the pH changes the shape of the enzyme.
C) is important, because changing the pH increases the temperature and the enzyme is denatured.
D) alters the substrate and, therefore, prevents the enzyme from attaching to the substrate.

Question 53

"I gave it a kick and you better believe it got going!" This statement sounds like

A) whatever needed the kick was very stable to begin with.
B) the kick served as activation energy.
C) the kicker served as a catalyst.
D) All of the choices are true.

Question 54

In order for an enzyme to do its job, the substrate must fit into the

A) coenzyme.
B) repressor site.
C) active site.
D) substrate complex.

Question 55

"Before you just dump that enzyme-active presoak into the washing machine, be sure to ____________ so it will do a better job."

A) rub it into the stained area to increase enzyme-substrate contact
B) turn up the water temperature to boiling to get the enzyme molecules moving faster
C) add chlorine bleach to the enzyme
D) dilute the enzyme with water

Question 56

Enzymes belong to which group of organic molecules?

A) carbohydrates
B) lipids
C) nucleic acids
D) proteins

Question 57

An enzyme that works in the stomach may not work in the small intestine because

A) the pH of the stomach contents is different than that found in the intestine.
B) the temperature is so different that the enzyme will be inhibited from taking action.
C) enzymatic competition will result in the denaturation of the substrate.
D) there will not be enough collisions to result in enzyme-substrate formation.

Question 58

"As I turned the temperature down, I found that there was a lower turnover number." This means

A) there were fewer substrates in the reaction.
B) fewer enzymes were synthesized.
C) that the enzyme was operating at its optimum.
D) the number of end products produced decreased.

Question 59

Which type of enzyme is most likely to be involved in the loss of fat during exercise?

A) carbohydrase
B) lipase
C) protease
D) trypsin

Question 60

Enzymatic competition involves

A) one type of enzyme and several substrates.
B) one type of substrate and several different types of enzymes.
C) one type of substrate and several different types of enzymes that all work on this same substrate.
D) no substrates, just two different enzymes acting on each other.

Question 61

The importance of enzymatic competition is that

A) different end products can be formed at different times when needed.
B) it reduces the amount of enzymes in the cell to an optimum.
C) it guarantees that all enzymes will form enzyme-substrate complexes.
D) no substrates will go unchanged by an enzyme.

Question 62

Physicians become very concerned when a person's body temperature rises above 40 $\degree$ C (104 $\degree$ F) since

A) many enzymes essential to life will be negatively affected, i.e., denatured or slowed in their actions.
B) nerve impulses will stop completely at this temperature.
C) the patient will lose the ability to communicate.
D) cell respiration will increase to the point of exhaustion.

Question 63

If a cofactor is not protein but another kind of organic molecule it is called a(n)

A) regulator lipid.
B) coenzyme.
C) substrate.
D) catalyst.

Question 64

Anti-viral drugs used to control certain viruses work by

A) causing the virus to replicate out of control
B) inhibiting the enzyme necessary for viral replication
C) making the virus more permeable to the drug
D) none of these

Question 65

These types of compounds are a group of unrelated organic molecules, either water-soluble or fat-soluble, used in the manufacture of final products by acting as coenzymes.

A) phosphates
B) acids
C) vitamins
D) enzymes

Question 66

Coenzymes such as ___________ are used to carry electrons to and from many kinds of oxidation/reduction reactions.

A) NAD⁺
B) Vitamin H
C) purines
D) zinc

Question 67

Which of the following statements concerning photosynthesis and aerobic cellular respiration is false?

A) Both are biochemical pathways.
B) Both involve many enzyme-controlled reactions linked together.
C) Both involve the transfer of energy.
D) Photosynthesis occurs exclusively in plants and aerobic cellular respiration occurs exclusively in animals.

Question 68

Which of the following pairs of terms go together?

A) anabolism-anaerobic cellular respiration
B) catabolism-aerobic cellular respiration
C) anabolism-aerobic cellular respiration
D) catabolism-photosynthesis

Question 69

The proton pump is responsible for the production of

A) ATPs.
B) oxygen.
C) ADP.
D) All of these answers are true.

Question 70

The proton pump involves the movement of

A) ADP.
B) hydrogen ions.
C) ATP.
D) All of these answers are true.

Question 71

ATP contains ____ high-energy phosphate bonds.

A) one
B) two
C) three
D) four

Question 72

Which statement below is FALSE regarding this chemical equation? ADP + P $\rightarrow$ ATP

A) This reaction is known as phosphorylation.
B) This reaction occurs in photosynthesis and cellular respiration.
C) This reaction represents energy being released into the environment for cellular use.
D) This reaction represents the formation of a high-energy phosphate bond.

Question 73

ATP, ADP, and AMP differ in the

A) type of sugar subunits they contain.
B) number of sugar subunits they contain.
C) number of adenine bases they contain.
D) number of phosphate groups they contain.

Question 74

The electron transport system uses ____ atoms.

A) hydrogen
B) carbon
C) nitrogen
D) All of these answers are true.

Question 75

NAD carries ____ to the electron transport system.

A) energy
B) oxygen
C) hydrogen electrons
D) water

Question 76

Which of the following molecules is LEAST like the other three in terms of function?

A) NAD
B) ATP
C) FAD
D) NADP

Question 77

NAD is a(n)

A) enzyme.
B) electron carrier.
C) product of photosynthesis.
D) oxygen carrier.

Question 78

The proton pump is the process of

A) producing glyceraldehyde-3-phosphate in the stroma.
B) forming ATP by creating a hydrogen ion gradient across a membrane.
C) converting fats and proteins into carbohydrates.
D) cellular respiration in plants.