Chapter 8 - Introduction to Metabolism

Question 1

What is the first law of thermodynamics?

Answer 1

Energy can be transferred and transformed, but it cannot be created or destroyed.

Question 2

What is the Second Law of Thermodynamics?

Answer 2

Every energy transfer or transformation increases the entropy (disorder) of the universe

Question 3

What is an emergent property of life which arises from orderly interactions between molecules?

Answer 3

Metabolism

Question 4

Metabolism

Answer 4

The totality of all chemical reactions in an organism.

Question 5

When a molecule is altered in a series of defined steps which results in a specific product. It is referred to as a ________________ .

Answer 5

Metabolic Pathway

Question 6

In a metabolic pathway. Each step is _________ by a specific ____________ .

Answer 6

catalyzed; enzyme

Question 7

A ____________ that speeds up a specific reaction is an __________ .

Answer 7

macromolecule; enzyme

Question 8

A process which breaks down complex molecules to simpler compounds is a ___________________ .

Answer 8

catabolic pathway

Question 9

___________ consume energy to build complex molecules from simple molecules.

Answer 9

Anabolic Pathways

Question 10

In _________ energy is stored by building bonds between atoms.

Answer 10

dehydration synthesis

Question 11

In ____________ , bonds between atoms are broken to release energy.

Answer 11

Hydrolysis

Question 12

When you ________ a reaction, you increase the speed of the reaction.

Answer 12

Catalyze

Question 13

________ is the capacity to cause change.

Answer 13

Energy

Question 14

________ is _______ associated with the relative motion of objects.

Answer 14

Kinetic energy

Question 15

_______ is ________ associated with the random movement of atoms or molecules.

Answer 15

Thermal energy

Question 16

The study of energy transformations which occur in a collection of matter is called ____________

Answer 16

Thermodynamics

Question 17

______ is in transfer from one object to another is called _______.

Answer 17

Thermal Energy; Heat

Question 18

_________ is the _______ available for release in a chemical reaction.

Answer 18

Chemical energy; potential energy

Question 19

_______ is a measure of molecular disorder or randomness.

Answer 19

Entropy

Question 20

__________ prevents the transfer of energy.

Answer 20

Insulation

Question 21

In an ___________ , energy and matter can be transferred between a system and its surroundings.

Answer 21

open system

Question 22

An organism is an ________ system

Answer 22

Open

Question 23

In a _________ , a process can proceed without requiring an input of energy.

Answer 23

spontaneous process

Question 24

A __________ requires an input of energy to proceed.

Answer 24

nonspontaneous process

Question 25

_________ is the portion of a system's energy that can perform work when temperature and pressure are uniform.

Answer 25

Free Energy

Question 26

Equation for the change in free energy.

Answer 26

(Delta)G = (Delta)H - T(Delta)S

Question 27

A spontaneous process will have a ________ (Delta)G

Answer 27

negative

Question 28

A nonspontaneous process will have a ________ (delta)G

Answer 28

positive

Question 29

An _________ reaction proceeds with a net release of free energy.

Answer 29

exergonic

Question 30

A __________ requires an input of energy to proceed.

Answer 30

Endergonic

Question 31

An exergonic reaction is a _________ reaction

Answer 31

downhill

Question 32

An endergonic reaction is __________.

Answer 32

uphill

Question 33

In ________ cells use an exergonic process to drive an endergonic one.

Answer 33

energy coupling

Question 34

__________ is the transfer of a phosphate group from ATP to another molecule

Answer 34

phosphorylation

Question 35

(delta)H is

Answer 35

change in enthalpy (or total energy)

Question 36

(Delta)S

Answer 36

Change in entropy

Question 37

If (delta)G is negative, a system uses _______ and becomes more _______.

Answer 37

free energy; stable

Question 38

The point at which forward and reverse actions occur at the same rate.

Answer 38

Equilibrium

Question 39

A ________ is a macromolecule that acts a catalyst.

Answer 39

Enzyme

Question 40

A _____ is a chemical agent that speeds up a reaction without being consumed by a reaction.

Answer 40

Catalyst

Question 41

__________ is the initial investment of energy required to start a reaction.

Answer 41

activation energy

Question 42

_______ speed up chemical reactions by lowering __________

Answer 42

Enzymes; energy barriers.

Question 43

___________ catalyzes the breakdown of ________ to glucose and fructoes

Answer 43

sucrase; sucrose

Question 44

Every chemical reaction between molecules involves ___________ and __________.

Answer 44

Bond breaking; bond forming

Question 45

_______ is the initial amount of energy required to break the bonds in reactants.

Answer 45

Activation Energy E(sub)A

Question 46

When enough energy is absorbed to break bonds; molecules become unstable. This is the _________.

Answer 46

Transition State

Question 47

_______ in the form of ________ often supplies activation energy.

Answer 47

Thermal energy; heat

Question 48

As atoms settle into new, more stable bonds, energy is ____________

Answer 48

released to the surroundings.

Question 49

In an exercongic reaction, ________ energy is released into the surroundings than was invested in breaking the old bonds.

Answer 49

more

Question 50

Catalysis

Answer 50

The process by which a catalyst selectively speeds up a reaction without itself being consumed

Question 51

An enzyme catalyzes a reaction by lowering the ___________ enough for the reaction to occur at moderate temperatures.

Answer 51

Activation Energy barrier

Question 52

Can an enzyme change the amount of free energy in a system?

Answer 52

No. It only speeds up a reaction that would eventually occur anyway.

Question 53

substrate

Answer 53

The reactant that an enzyme acts on.

Question 54

If an enzyme binds to a substrate. It forms an ________

Answer 54

Enzyme substrate complex.

Question 55

The _____ is the region on the enzyme, often a pocket or groove, that binds to the substrate

Answer 55

active site

Question 56

Interactions between chemical groups on the substrate and the active site create an

Answer 56

induced fit

Question 57

The substrate is typically held in the enzyme’s active site by ________.

Answer 57

weak bonds

Question 58

How do you speed up the rate of an enzyme-catalyzed reaction?

Answer 58

Increase the concentration of substrate

Question 59

When all enzyme molecules have their active sites engaged, the enzyme is ______________.

Answer 59

saturated

Question 60

If the enzyme is saturated, the reaction rate can only be sped up by:

Answer 60

adding more enzyme

Question 61

Enzyme activity can be affected by environmental factors, such as ___________ and __________.

Answer 61

temperature: pH

Question 62

If you go over the optimal temperature of an enzyme, the reaction rate will _______

Answer 62

decrease

Question 63

An enzyme that works in the stomach would work at a pH of about

Answer 63

2

Question 64

An enzyme that works in the intestine would work at a pH of about

Answer 64

8

Question 65

Nonprotein helpers that bind to the enzyme permanently, or reversibly with the substrate

Answer 65

Cofactors

Question 66

Inorganic cofactors

Answer 66

iron; copper zinc (all ions)

Question 67

Organic cofactors are called

Answer 67

coenzymes

Question 68

What is an example of an organic coenzyme?

Answer 68

A vitamin

Question 69

Enzymes are selectively inhibited by:

Answer 69

Enzyme inhibitors

Question 70

Are the actions of an enzyme inhibitor permanent?

Answer 70

If the inhibitor bonds to an enzyme using a covalent bond, the inhibition is usually irreversible. Many inhibitors however bond using weak bonds. In this case the inhibition can be temporary.

Question 71

A ___________ closely resembles a substrate and can bind to an enzymes active site.

Answer 71

competitive inhibitor

Question 72

How would you overcome an enzyme inhibitor?

Answer 72

Increase the amount of substrate.

Question 73

What inhibitor binds to an enzyme away from the active site?

Answer 73

A noncompetitive inhibitor. It changes the shape of the enzyme. This makes the active site less effective at catalyzing the reaction.

Question 74

What are examples of enzyme inhibitors?

Answer 74

Toxins; pesticides, sarin gas

Question 75

Why are enzymes important in metabolism?

Answer 75

Enzyme activity allows metabolic pathways to work.

Question 76

How to cells regulate metabolism?

Answer 76

By switching on or off the genes that code for specific enzymes. Another way is to regulate the activity of specific enzymes.

Question 77

In ______________________ the end product of a pathway shuts down that pathway.

Answer 77

feedback regulation

Question 78

What prevents a cell from wasting resources by producing more product than is needed?

Answer 78

Feedback inhibition.

Question 79

When a regulatory molecule binds to a protein at one site and affects the protein’s function at another site

Answer 79

Allosteric regulation

Question 80

What is the effect of Allosteric Regulation?

Answer 80

To inhibit or stimulate enzyme activity.

Question 81

In ___________, substrate binding to one active site triggers a shape change in the enzyme that stabilizes the active form for all other sites

Answer 81

cooperativity