Chapter 15: Metabolism - Basic Concepts

Question 1

After digestion, the many small molecules are processes into key molecules of ____________

Answer 1

Metabolism

Question 2

What is produced from the complete oxidation of acetyl CoA?

Answer 2

ATP

Question 3

Energy is required to meet three fundamental needs:

Answer 3

Power muscle contraction, cell movement and biosynthesis

Question 4

Obtain energy by capturing sunlight:

Answer 4

Phototrophs

Question 5

Obtain energy through the oxidation of carbon dioxide

Answer 5

Chemotrophs

Question 6

Molecules are degraded or synthesized stepwise in a series of reactions termed:

Answer 6

Metabolic pathways

Question 7

What is the energy currency of life?

Answer 7

ATP

Question 8

ATP can be formed by the oxidation of what?

Answer 8

Carbon fuels

Question 9

Although many reactions occur inside a cell, a limited number of what are common in all metabolic reactions?

Answer 9

Reaction types and cell intermediates

Question 10

Are metabolic pathways highly regulated?

Answer 10

Yes

Question 11

Enzymes involved in metabolism are organized into ______ complexes

Answer 11

Large

Question 12

The entire set of cellular metabolic reactions are called:

Answer 12

Intermediary metabolism

Question 13

Metabolic pathways can be divided into two types:

Answer 13

Catabolic and anabolic

Question 14

Pathways that combust carbon fuels to synthesize ATP or ion gradients

Answer 14

Catabolic

Question 15

Pathways that use ATP and reducing power to synthesize large biomolecules

Answer 15

Anabolic

Question 16

Catabolic pathways use what carriers?

Answer 16

NADH
FADH2

Question 17

Anabolic pathways use what carriers?

Answer 17

NADPH

Question 18

Does catabolic reactions use or make ATP?

Answer 18

Make

Question 19

Anabolic reactions use or make ATP?

Answer 19

Use

Question 20

NADPH is used as a ___________ agent in catabolic reactions

Answer 20

Reducing

Question 21

Can function anabolically or catabolically

Answer 21

Amphibolic pathways

Question 22

Although anabolic and catabolic pathways may have reactions in common, what is always distinct?

Answer 22

Regulated, irreversible reactions

Question 23

2 criteria must be met to construct a metabolic pathway:

Answer 23

• The individuals reactions (substrate and enzymes) must be specific
• The pathway in total must be thermodynamically favorable

Question 24

A thermodynamically unfavorable reaction in a pathway can be made to occur by _________ it to a more favorable reaction

Answer 24

Coupling

Question 25

Energy derived from fuels or light is converted into:

Answer 25

Adenosine triphosphate (ATP)

Question 26

The hydrolysis of ATP is exergonic or endergonic?

Answer 26

Exergonic

Question 27

The hydrolysis of ATP is exergonic because the triphosphate unit contains two phosphoanyhydride bonds that are ______

Answer 27

Unstable

Question 28

ATP has a high or low Phosphoryl-transfer potential?

Answer 28

High

Question 29

What is the Phosphoryl-transfer potential?

Answer 29

Tendency of molecules to transfer a phoshoryl group to an acceptor molecule

Question 30

ATP has a high phosphoryl-transfer potential because of four key factors:

Answer 30

Charge repulsion, resonance stabilization, increase in entropy, stabilization by hydration

Question 31

ATP has a phosphoryl-transfer potential that is ______________ among the biologically important phosphorylated molecules. This position enables ATP to function efficiently as a ________ of phosphoryl groups

Answer 31

Intermediate, carrier

Question 32

Creatine phosphate can regenerate ___ to ___

Answer 32

ADP, ATP

Question 33

Phosphate esters are thermodynamically ________, yet they are kinetically ______

Answer 33

Unstable, stable

Question 34

Phosphate esters are kinetically stable because they inherent ________ charges that resist ________.

Answer 34

Negative, hydrolysis

Question 35

Because phosphate esters are kinetically stable, they are ideal _____________ molecules

Answer 35

Regulatory

Question 36

Phosphate esters are added to molecules by _________ and removed by _______________

Answer 36

Kinases, phosphatases

Question 37

Cells maintain a very low or high concentration of ATP

Answer 37

High

Question 38

ATP prevents the formation of protein ___________ and ____________ those that form. ATP maintains ________ solubility

Answer 38

Aggregates, dissolve, protein

Question 39

Recent research suggests that ATP may function as a biological ____________.

Answer 39

Hydrotrope

Question 40

The immediate donor of free energy for biological activities:

Answer 40

ATP

Question 41

ATP is limited, therefore to must do what?

Answer 41

Be constantly recycled to provide energy too power the cell

Question 42

Oxidation reactions involve the ______ of electrons

Answer 42

Loss

Question 43

Reduction reactions involve the ______ of electrons

Answer 43

Gain

Question 44

The paired reactions of both oxidation and reduction are called:

Answer 44

Oxidation-reduction or redox

Question 45

The more reduced a carbon atom is, the more free energy is released upon _____________.

Answer 45

Oxidation

Question 46

The carbon atoms in fuels are oxidized to yield ___ and the electrons are ultimately accepted by oxygen to form ___

Answer 46

CO2, H2O

Question 47

Why are fats a more efficient food source than glucose?

Answer 47

Because they are more reduced

Question 48

Oxidation of the carbon atom may form a compound with high _____________-_________potential that can then be used to synthesize ___

Answer 48

Phosphoryl-transfer, ATP

Question 49

Two characteristics are common to activated carriers:

Answer 49

- Carriers are kinetically stable in the absence of specific catalysts - The metabolism of activated groups is accomplished with a small number of carriers

Question 50

What is an activated carrier of phosphoryl groups?

Answer 50

ATP

Question 51

Other activated carriers in biochemistry are often derived from what?

Answer 51

Vitamins

Question 52

NAD+ and FAD carry activated electrons derived from ____________ _________

Answer 52

Oxidation fuels

Question 53

(NADP+) is an activated carrier of electrons for what?

Answer 53

Reductive biosynthesis

Question 54

Coenzyme A is an activated carrier for what?

Answer 54

Acyl groups

Question 55

The transfer of the acyl group is exergonic or endergonic?

Answer 55

Exergonic

Question 56

Why is the transfer of acyl groups exergonic?

Answer 56

Because the thioester is unstable

Question 57

Pantothenate, which is readily obtained from egg yolks, is a component of:

Answer 57

Coenzyme A

Question 58

What vitamins function as coenzymes?

Answer 58

B

Question 59

What are the three regulatory controls in homeostasis?

Answer 59

1. The amount of enzymes present 2. The catalytic activity of enzymes 3. The accessibility of substrates

Question 60

The quantity of enzyme present can be regulated at the level of what?

Answer 60

Gene transcription

Question 61

Catalytic activity is regulated __________________ or by ____________ __________ _______________

Answer 61

allosterically, reversible covalent modification

Question 62

Hormones coordinate metabolic activity, often by:

Answer 62

Instigating the covalent modification of allosteric enzymes.

Question 63

The energy status of the cell is often an important regulator of what?

Answer 63

Enzyme actvity

Question 64

Two common means are used to assess energy status:

Answer 64

Energy charge and phosphorylation potential

Question 65

Opposing reactions such as fatty acid synthesis and degradation may occur in different what?

Answer 65

Cellular compartments

Question 66

Regulating the flux of substrates between compartments is used to regulate:

Answer 66

Metabolism