Chapter 3: Energy, Catalysis, and Biosynthesis

Question 1

allows the cell to precisely control its metabolism

Answer 1

catalysis

Question 2

the sum total of all the chemical reactions it needs to carry out to survive, grow, and reproduce.

Answer 2

metabolism

Question 3

Two opposing streams of chemical reactions occur in cells:

Answer 3

• catabolic pathway
• anabolic pathway

Question 4

The breakdown foodstuffs into smaller molecules, thereby generating both a useful form of energy for the cell and some of the small molecules that the cell needs as building blocks.

Answer 4

catabolic pathway (catabolism)

Question 5

It uses the energy harnessed by catabolism to drive the synthesis of the many molecules that form the cell.

Answer 5

anabolic pathway (anabolism) or biosynthesis

Question 6

The universal tendency of things to become disordered is expressed in a fundamental law of physics called the ________.

Answer 6

second law of thermodynamics.

Question 7

This law states that in the universe as a whole, or in any isolated system (a collection of matter that is completely cut off from the rest of the universe), the degree of disorder can only increase.

Answer 7

second law of thermodynamics

Question 8

systems will change spontaneously toward those arrangements that have the greatest probability.

Answer 8

second law

Question 9

The measure of a system’s disorder.

Answer 9

entropy

Question 10

the _________ the disorder, the ________ the entropy

Answer 10

greater - greater

Question 11

What law expresses “ systems will change spontaneously toward arrangements with greater entropy”?

Answer 11

second law of thermodynamics

Question 12

A cell is not an _________ system.

Answer 12

isolated

Question 13

the chemical reactions inside a cell must increase the __________ of the entire system

Answer 13

total entropy

Question 14

According to the ______________, energy cannot be created or destroyed—but it can be converted from one form to another

Answer 14

first law of thermodynamics

Question 15

a product of energy conversion

Answer 15

heat

Question 16

How does solar energy enter the living world?

Answer 16

through photosynthesis

Question 17

a process that converts the electromagnetic energy in sunlight into chemical-bond energy in cells.

Answer 17

photosynthesis

Question 18

Give examples of photosynthetic organisms:

Answer 18

plants, algae, and some bacteria

Question 19

In the first stage of photosynthesis, energy from sunlight is captured and transiently stored as chemical-bond energy in specialized molecules called _________.

Answer 19

activated carriers

Question 20

In the second stage of photosynthesis, the activated carriers are used to help drive a ___________ process.

Answer 20

carbon fixation

Question 21

In this process, sugars are manufactured from carbon dioxide gas (CO2).

Answer 21

carbon fixation process

Question 22

In plants and animals, the chemical energy is extracted from food molecules by a process of ________.

Answer 22

gradual oxidation or controlled burning

Question 23

The Earth’s atmosphere is about how much oxygen?

Answer 23

21%

Question 24

In the presence of oxygen, the most energetically stable form of carbon is ______ and that of hydrogen is ______.

Answer 24

CO2; H2O

Question 25

The step-wise process by which food molecules are broken down to produce energy is known as cell respiration.

Answer 25

cell respiration

Question 26

This means the addition of oxygen atoms to a molecule.

Answer 26

oxidation

Question 27

involves the removal of electrons from an atom

Answer 27

oxidation

Question 28

involves the addition of electrons to an atom

Answer 28

reduction

Question 29

the acceleration of the specific chemical reactions needed to sustain life

Answer 29

catalysis

Question 30

energy that must be acquired by a molecule to undergo a chemical reaction (for example a collision with other molecules)

Answer 30

activation energy

Question 31

a substance that can lower activation energy

Answer 31

catalyst

Question 32

the most effective catalyst

Answer 32

enzymes

Question 33

_________ reactions are reductions

Answer 33

hydrogenation reactions

Question 34

and the reverse ___________ are oxidations.

Answer 34

dehydrogenation reactions

Question 35

energy that can be harnessed to do work or drive chemical reactions

Answer 35

free energy

Question 36

Each enzyme binds tightly to one or two molecules, called ________.

Answer 36

substrates

Question 37

A substance that can lower the activation energy of a reaction is termed a ______________.

Answer 37

catalyst

Question 38

The useful energy in a system

Answer 38

free energy or G

Question 39

it measures the amount of dis- order

Answer 39

ΔG

Question 40

those that create disorder in the universe by decreasing the free energy of the system to which they belong;

Answer 40

Energetically favorable reactions

Question 41

they have a negative ΔG

Answer 41

Energetically favorable reactions

Question 42

they create order in the universe

Answer 42

Energetically unfavorable reactions

Question 43

they have a positive ΔG

Answer 43

Energetically unfavorable reactions

Question 44

___________ is increased when useful energy (harnessed) is dissipated as heat (useless).

Answer 44

Disorder

Question 45

useful energy; can be harnessed and drive a chemical reaction

Answer 45

Free Energy / G

Question 46

the difference in energy in reactant and product molecules

Answer 46

free energy chance / ∆G

Question 47

The ratio of substrate to product at this equilibrium point

Answer 47

equilibrium constant, K

Question 48

the energy released in the binding interaction

Answer 48

binding energy

Question 49

the energy is stored as chemical-bond energy in a set of __________

Answer 49

activated carriers

Question 50

energetically favorable reaction is used to drive an energetically unfavorable one, so that an activated carrier or some other useful molecule is produced.

Answer 50

coupled reaction

Question 51

he wondered how energy is transformed during chemical reactions in cells.

Answer 51

Otto Meyerhof

Question 52

a pioneer in the field of cell metabolism

Answer 52

Otto Meyerhof

Question 53

He recognized that between its initial entry in the form of food and its final dissipation as heat, a large amount of energy must be made available by a series of interme- diate chemical steps that allow the cell or organism to maintain itself in a state of dynamic equilibrium.

Answer 53

Otto Meyerhof

Question 54

He determined that working muscles give off heat, both as they contract and as they recover; further, he found that the amount of heat correlates with how hard the muscle is working.

Answer 54

Archibald “A.V.” Hill

Question 55

The most important and versatile of the activated carriers in cells.

Answer 55

ATP (adenosine 5ʹ-triphosphate)

Question 56

Any reaction that involves the transfer of a phosphate group to a molecule.

Answer 56

phosphorylation reaction.

Question 57

the most abundant activated carrier in cells.

Answer 57

ATP

Question 58

The ultimate source of energy for most living organisms

Answer 58

sun

Question 59

release energy by breaking down organic molecules, including foods, through oxidative pathways.

Answer 59

Catabolic reactions

Question 60

generate the many complex organic molecules needed by the cell, and they require an energy input.

Answer 60

anabolic reactions

Question 61

catalyze reactions by binding to particular substrate molecules in a way that lowers the activation energy required for making and breaking specific covalent bonds.

Answer 61

Enzymes

Question 62

govern all of the associations (and dissociations) that occur between macromolecules and small molecules in the cell.

Answer 62

Equilibrium constants

Question 63

carries high-energy phosphate groups

Answer 63

ATP

Question 64

carry high-energy electrons

Answer 64

NADH and NADPH

Question 65

provide the carbon skeletons for the formation of macromolecules.

Answer 65

food molecules