Chapter 3

Front 1

All living organisms require energy to ______?

Back 1

Power muscle.

Pump blood.

Absorb nutrients.

Exchange respiratory gases.

Synthesize new molecules.

Establish cellular ion concentrations

Front 2

Glucose is broken down through _____ pathways.

Back 2

Metabolic.

Front 3

Describe the two classes of energy.

Back 3

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Front 4

Describe chemical energy (one form of potential energy) and the various forms of kinetic energy.

Back 4

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Front 5

List the three important molecules within the body that function primarily in chemical energy.

Back 5

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Front 6

State the first law and second law of thermodynamics.

Back 6

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Front 7

Explain why energy conversion is always less than 100%.

Back 7

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Front 8

Define energy.

Back 8

Capacity to do work

Front 9

What are the 2 classed of energy?

Define each.

Back 9

Potential energy—stored energy (energy of position)

Kinetic energy—energy of motion

Front 10

Potential energy and the plasma membrane

Back 10

Concentration gradient exists across plasma membrane

---Boundary between inside and outside of cell

Front 11

Potential energy and electron shells

Back 11

Electrons move from a higher- to lower-energy shell.

Kinetic energy can be harnessed to do work

Front 12

Potential energy must be converted to_____ energy before it can do work.

Back 12

Kinetic.

Front 13

Define Chemical Energy.

What is it used for?

Back 13

One form of potential energy.

Energy stored in a molecule’s chemical bonds. The most important form of energy in the human body.

Used for: Movement

Molecule synthesis

Establishing concentration gradients

Present in all chemical bonds

Released when bonds are broken during reactions

Front 14

What are the molecules that function in chemical energy storage?

Back 14

Triglycerides (long term energy storage in adipose tissue).

Glucose (glycogen stores in liver and muscle)

ATP (stored in all cells; produced continuously and used immediately)

Front 15

How is a protein used/needed during chemical energy?

Back 15

Stored chemical energy and can be used as a fuel molecule.

Has more important structural and functional role in body

Front 16

What is electrical energy?

Back 16

Electrical energy: movement of charged particles

---E.g., electricity or the movement of ions across the plasma membrane of a neuron

Front 17

What is mechanical energy?

Back 17

Mechanical energy: exhibited by objects in motion due to applied force

---E.g., muscle contraction for walking

Front 18

What is sound energy?

Back 18

Sound energy: molecule compression caused by a vibrating object

E.g., sound waves causing vibration of the eardrum in the ear

Front 19

What are the 5 types of kinetic energy forms?

Back 19

Electrical energy

Mechanical energy

Sound energy

Radiant energy

Heat

Front 20

What is radiant energy?

Back 20

The energy of electromagnetic waves.

Vary in wavelength and frequency .

Higher frequencies with greater radiant energy.

Frequencies higher than visible light

-Penetrate body and mutate DNA

-Cells protected by melanin

Visible light detected by retinal cells of the eye.

-Relayed along optic nerve to brain

Front 21

What is heat?

Back 21

Kinetic energy of random motion.

Usually not available to do work.

Measured as the temperature of a substance

Front 22

What is Thermodynamics?

Back 22

Thermodynamics—study of energy transformations.

Means Heat change.

Front 23

Energy can change forms, EXAMPLES!

Back 23

A burning candle converts chemical energy to light and heat energy.

Retinal cells convert light energy into electrical energy of a nerve impulse.

Chemical energy in food converted to another chemical form, then into mechanical energy

Front 24

What is the first law of thermodynamics?

Back 24

Energy can neither be created nor destroyed; it can only change in form

Front 25

What is the second law of thermodynamics?

Back 25

When energy is transformed, some energy is lost to heat.

-The amount of usable energy decreased

-E.g., moving around to warm up on a cold day

-As chemical energy converts to mechanical energy, heat is produced

Front 26

Gramma rays are the _______ rays in the universe.

Back 26

Dangerous.

Front 27

What is the energy of position?

Back 27

Potential Energy.

Front 28

What is the energy of motion?

Back 28

Kinetic Energy.

Front 29

A sodium ion moving down its concentration gradient is an example of what kind of energy?

Back 29

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Front 30

Muscle contraction is an example of what kind of energy?

Back 30

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Front 31

Explain what occurs in a chemical reaction.

Back 31

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Front 32

Distinguish between reactants and products.

Back 32

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Front 33

Describe the three classifications of chemical reactions.

Back 33

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Front 34

Distinguish between catabolism and anabolism.

Back 34

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Front 35

Discuss the exchange that takes place in an oxidation reduction reaction.

Back 35

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Front 36

Explain ATP cycling.

Back 36

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Front 37

Define chemical reaction rate

Back 37

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Front 38

Explain activation energy.

Back 38

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Front 39

Dene Metabolism.

Back 39

All biochemical reactions in living organisms

Front 40

What is a chemical reaction?

Back 40

Occur when chemical bonds in existing molecular structures are broken.

New bonds formed.

Expressed as chemical equation

Front 41

What is a chemical equation?

Back 41

Reactants and Products.

Front 42

What is a reactant?

Back 42

Substances present prior to start of a chemical reaction.

Written on left side of equation.

Front 43

What is a product?

Back 43

Substances formed by the reaction.

Written on right side of equation.

A + B → C

A and B are reactants C is the product.

Arrow indicates reaction direction.

In a balanced equation, number of elements are equal on both sides of the reaction

Front 44

What are the 3 criteria that chemical reactions are classified based on?

Back 44

1.Changesin chemical structure

2.Changesin chemical energy

3.Whetherthe reaction is irreversible or reversible

Front 45

What are 3 different chemical structure changes?

Back 45

1.Decomposition reactions

2.Synthesis reactions

3.Exchange reactions

Front 46

What is a decomposition reaction?

Back 46

Initial large molecule broken down into smaller structures

AB → A + B

E.g., hydrolysis reaction of sucrose into glucose and fructose

All decomposition reactions in the body are referred to as catabolism or catabolic reactions

Front 47

What is a synthesis reaction?

Back 47

Two or more structures combined to form a larger structure.

A + B → AB

E.g., dehydration synthesis reaction forming a dipeptide

Anabolism is the collective term for all synthesis reactions in the body

Front 48

What is an exchange reaction?

Back 48

Groups exchanged between two chemical structures.

Has both decomposition and synthesis components.

Most prevalent in human body.

AB + C → A + BC

E.g., production of ATP in muscle tissue

Front 49

What is an Oxidation-reduction reaction?

Back 49

Electrons moved from one chemical structure to another.

Structure that loses an electron, oxidized during oxidation.

Structure that gains an electron, reduced during reduction.

Reactions always occur together.

-Electrons may be moved alone or with a hydrogen ion

OIL RIG = Oxidation is the lost of electrons, Reduction is the gain of electrons.

Front 50

Define Nicotinamide adenine dinucleotide (NAD+).

Back 50

Modified dinucleotide containing nicotinamide

Important in ATP synthesis

Front 51

When an energy-rich molecule (glucose) is oxidized, it gives off _______ ______ atoms.

Back 51

2 Hydrogen.

Front 52

NAD+ reduced gains both a ______ ion and ______ ________.

Back 52

Hydrogen.

2 Electrons.

Front 53

What is a exergonic reaction?

Back 53

Reactants with more energy within their chemical bonds than products.

Energy released with net decrease in potential energy.

E.g., decomposition reactions

Front 54

What is a endergonic reaction?

Back 54

Reactants with less energy within their chemical bonds than products.

Energy supplied with a net increase in potential energy.

E.g., synthesis reactions

Front 55

What is ATP cycling?

Back 55

Continuous formation and breakdown of ATP

Front 56

What happens when ATP forms when energy is released in an exergonic reaction?

Back 56

Fuel molecules from food are oxidized.

Energy in their bonds transferred to ADP and free phosphate to form ATP

Front 57

What happens when ATP is oxidized?

Back 57

Released energy used for energy-requiring processes.

Front 58

What happens when only a few seconds of energy worth of ATP is present?

Back 58

Formation of ATP occurs continuously to provide energy.

Front 59

What is the irreversible reaction?

Back 59

Net loss of reactants and a net gain in products

A + B → AB or AB → A + B

Front 60

What is the reversible reaction?

Back 60

Does not proceed only to the right

Reactants become products and products become reactants at an equal rate

No net change in concentration of either reactants or products—equilibrium

A + B ⇆ AB

Front 61

Reversible reaction remains in ___________ if left undistrubed.

Back 61

Equilibrium.

Increase in reactants or decrease in products drives equation to the right.

-----Additional product formed until new equilibrium reached

Decrease in reactants or increase in products drives equation to the left

-----Additional reactants formed until new equilibrium reached

Front 62

What is the reversible reaction for the way carbon dioxide reacts water to form carbonic acid?

Back 62

CO2 + H2O ⇆ H2CO

Front 63

What is the reversible reaction for the way carbonic acid dissociates to yield bicarbonate ion and hydrogen ion?

Back 63

CO2 + H2O ⇆ H2CO3 ⇆ H+ + HCO3–

Front 64

What is the type of reaction that is important for blood transport of carbon dioxide and maintaining acid-base balance?

Back 64

Reversible Reaction?

Front 65

Define Reaction Rate.

Back 65

Measure of how quickly a chemical reaction takes place

Front 66

Define Activation Energy (Ea).

Back 66

Energy required to break existing chemical bonds.

A primary factor determining reaction rate

Front 67

How can you overcome the activation energy?

Back 67

In a lab, increasing temperature provides energy to break bonds.

Significant temperature increase in a cell would denature proteins.

------Protein catalysts called enzymes are used instead

Front 68

Is the formation of a dipeptide a decomposition or synthesis reaction?

Back 68

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Front 69

Is it exergonic or endergonic?

Back 69

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Front 70

Is it an example of anabolism or catabolism?

Back 70

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Front 71

What molecule is formed from exergonic reactions and used as the energy currency for endergonic reactions and other energy-requiring processes in the cell?

Back 71

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Front 72

What is the term for the energy required to break existing chemical bonds?

Back 72

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Front 73

Describe the general function of enzymes.

Back 73

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Front 74

Describe the key structural components of enzymes.

Back 74

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Front 75

Identify the places in the body where enzymes may be found.

Back 75

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Front 76

Explain the steps by which an enzyme catalyzes a reaction.

Back 76

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Front 77

Describe cofactors and their role in reactions.

Back 77

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Front 78

Identify the six major classes of enzymes and the general functions of enzymes in each class.

Back 78

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Front 79

Describe the naming conventions for enzymes.

Back 79

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Front 80

Define how enzyme and substrate concentration affect reaction rates.

Back 80

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Front 81

Explain the effect of temperature on enzymes.

Back 81

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Front 82

Describe how pH changes affect enzymes.

Back 82

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Front 83

What happens when you have a temperature?

Back 83

Your proteins would begin to denature and functions would stop occurring.

Front 84

Describe how competitive and noncompetitive inhibitors control enzyme action.

Back 84

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Front 85

Distinguish between a metabolic pathway and a multienzyme complex.

Back 85

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Front 86

Explain the role of negative feedback in enzyme regulation.

Back 86

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Front 87

Identify and explain the processes involving phosphate that commonly are used to regulate enzymes.

Back 87

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Front 88

Define Catalyst.

Back 88

that accelerate normal physiologic activities

Front 89

Define uncatalyzed.

Back 89

Has no enzyme present.

A.K.A. Spontaneous reaction

Front 90

Define Catalyzed.

Back 90

An Enzyme present.

Front 91

Enzymes______.

Back 91

Decrease activation energy of cellular reactions.

Only facilitate reactions that would already occur.

Increases the rate of product formation.

Front 92

Activation energy ______ to initiate a reaction.

Back 92

Required.

Front 93

The presence of an enzyme lovers require _____.

Back 93

Activation of Energy (Ea).

Front 94

Most enzymes ae _____ ______.

Back 94

Global proteins.

--Range in size from small (60 amino acids) to large (2500 amino acids).

--Unique 3-dimensional structure in protein chain called active site.

--Temporarily forms enzyme-substrate complex.

Front 95

Active site's _____ of shape.

Back 95

Specificity.

Permits only a single substrate to bind.

Helps catalyze only one specific reaction.

Front 96

What are some locations of enzymes?

Back 96

Some remain within cells

--E.g., DNA polymerase, which helps form new DNA

Some become embedded in plasma membrane

--E.g., lactase in walls of small intestine cells helps digest lactose

Some are secreted from the cell

--E.g., pancreatic amylase released from pancreas to participate in starch digestion

Front 97

What happens when an enzyme catalysis?

Back 97

1.Substrate enters active site, forming enzyme-substrate complex 2.Enzyme changes shape slightly, resulting in even closer fit (induced fit model )

3.Change in enzyme shape stresses chemical bonds, permitting new bonds to be formed

4.Products are released; enzyme may repeat the process.

Front 98

Define Cofactor.

Back 98

Molecules or “helper” ions required to ensure that a reaction occurs.

Associated with particular enzyme.

Nonprotein organic or inorganic structure

-Inorganic cofactors attach to enzyme

---E.g., zinc ion required for carbonic anhydrase to function

-Organic cofactors called coenzymes

---E.g., vitamins or modified nucleotides serving as coenzymes

Front 99

What are the 6 major functional classes that enzymes are organized into?

Back 99

1.Oxidoreductase

̶E.g., enzymes in this class participate in oxidation-reduction reactions ̶Dehydrogenase

2.Transferase

̶E.g., all enzymes in this class of a transfer atoms or molecules between chemical structures

̶Kinase

3.Hydrolase 4.Isomerase 5.Ligase 6.Lyase

Front 100

Enzymes names are based on?

Back 100

Name of substrate or product.

Subclass.

Suffix –ase

E.g., pyruvate dehydrogenase transfers hydrogen from pyruvate.

E.g., DNA polymerase helps form DNA.

E.g., lactase digests lactose

Front 101

What are some conditions that influence the reaction rate?

Back 101

Increases in enzyme concentration.

Increases in substrate concentration.

---Increases only up to point of saturation

---Saturation—so much substrate is present that all enzyme molecules are engaged in reaction

Front 102

What is the effect of a 3-dimensional shape of enzymes dependent on temperature for the influence of a reaction rate?

Back 102

Human enzymes function best at optimal temperature.

---Usually 37ºC (98.6ºF).

Moderate fever

---Results in more efficient enzyme activity.

Severe increases in temperature.

---Cause protein denaturation with loss of function

Front 103

What is the effect of pH on the influence of a reaction rate?

Back 103

Enzymes function best at optimal pH.

-Between pH of 6 and 8 for most enzymes

-Changes in H+ disrupt electrostatic interactions

-Enzyme loss of shape, denaturation

-Optimal pH may differ.

---E.g., enzymes working in the lower pH of the stomach

Front 104

Define Inhibitor.

Function/s?

Back 104

Prevents overproduction of product.

Later release of inhibitor allows it to function and catalysis continues.

Inhibitors can be competitive or noncompetitive

Front 105

What is a competitive inhibitor?

Back 105

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Front 106

What may be oxidized to generate ATP?

Back 106

Glucose, amino acids, and fatty acids.

Front 107

What is a noncompetitive inhibitor?

Back 107

Do not resemble substrate.

Bind a site other than active site (allosteric site).

Induce conformational change to enzyme and active site.

Also called allosteric inhibitors.

Not influenced by concentration of substrate

Front 108

What is the metabolic pathway?

Back 108

Series of enzymes.

Product of one enzyme becomes substrate of the next.

Front 109

What is a multienzyme complex?

Back 109

Group of attached enzymes.

Work in a sequence of reactions

E.g., pyruvate dehydrogenase

Front 110

What are some advantages of the multienzyme complex?

Back 110

Less likely substance will diffuse away into different biochemical pathway.

Single complex can be regulated rather than individual enzymes

Front 111

What is the product from metabolic pathway acts as an allosteric inhibitor?

(Pathways regulated through negative feedback)

Back 111

-Turns off enzyme early in pathway.

-As more product accumulates, less product formed.

-As less product accumulates, more product formed

Front 112

What is Phosphorylation?

(Regulation on Enzymes)

Back 112

-Addition of phosphate group.

-Performed by protein kinases.

-Turns on some enzymes; turns off others

Front 113

What is Dephosphorylation?

(Regulation on Enzymes)

Back 113

-Removal of phosphate group.

-Performed by phosphatases

-Turns on some enzymes; turns off others

Front 114

What is the relationship between enzymes and activation energy?

Back 114

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Front 115

What is the active site of an enzyme?

Back 115

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Front 116

Increasing the concentration of a substrate increases the rate of reaction up until what point?

Back 116

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Front 117

Which type of inhibitor resembles the substrate and binds to the enzyme active site?

Back 117

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Front 118

What two processes involve phosphate and are commonly used to regulate enzymes in a metabolic pathway or a multienzyme complex?

Back 118

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Front 119

*Drugs as Enzyme Inhibitors*

Back 119

Drugs increase or decrease specific enzyme activity.

Front 120

Clinical view of Lactose Intolerance

Back 120

-Caused by a deficiency in lactase or abnormal lactase.

-Lactase is required to break bond in lactose into glucose and galactose

-Common in older adults

-Common symptoms: abdominal upset, nausea, diarrhea, bloating, gas

-Treated with lactase enzymes, avoidance of milk, or drinking lactose-free milk

Front 121

Write the overall formula for glucose oxidation.

Back 121

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Front 122

Name the two pathways that generate ATP.

Back 122

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Front 123

List the four stages of glucose oxidation and where each stage occurs within a cell.

Back 123

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Front 124

Summarize the metabolic pathway of glycolysis, including (a) where it occurs in a cell, (b) if it requires oxygen, (c) the initial substrate and final product, and (d) the molecules formed during energy transfer.

Back 124

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Front 125

Explain the enzymatic reaction of the intermediate stage, including (a) where it occurs in a cell, (b) if it requires oxygen, (c) the initial substrate and final product, and (d) the molecules formed during energy transfer.

Back 125

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Front 126

Define decarboxylation.

Back 126

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Front 127

Summarize the metabolic pathway of the citric acid cycle including (a) where it occurs in a cell, (b) if it requires oxygen, (c) the initial substrate and final product, and (d) the molecules formed during energy transfer.

Back 127

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Front 128

Describe the importance of NADH and FADH2 in energy transfer.

Back 128

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Front 129

Explain the actions that take place in the electron transport system.

Back 129

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Front 130

Calculate the number of ATP molecules produced in cellular respiration if oxygen is not available and if oxygen is available.

Back 130

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Front 131

Explain the fate of pyruvate when oxygen is in short supply.

Back 131

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Front 132

Describe the impact on ATP production if there is insufficient oxygen.

Back 132

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Front 133

Describe the entry point in the metabolic pathway of cellular respiration for both fatty acids and amino acids.

Back 133

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Front 134

Define Cellular Respiration.

Back 134

•Exergonicmultistep metabolic pathway•Organicmolecules oxidized and disassembled by a series of enzymes

•Potentialenergy in chemical bonds released•Energyused to make ATP (endergonic process)•Oxygenrequired

Front 135

What is glucose Oxidation?

Back 135

Step-by-step breakdown of glucose with energy release

Carbon dioxide and water formed

Front 136

What is the pathway for ATP production?

Back 136

–Energyfrom broken bonds used to attach phosphate group to ADP

–Energycan be used directly

oLeastcommon

oSubstrate level phosphorylation

–-Energycan be used indirectly

oMostcommon

oEnergyfirst released to coenzymes

oThenenergy transferred to form ATP

oOxidative phosphorylation

Front 137

What is the cellular location of glucose oxidation?

Back 137

Enzymes found in both

Cytosol—semifluid cell contents of the cell Mitochondria—small cellular organelles

(20 different enzymes required)

Front 138

What are the 4 stages of glucose oxidation?

Back 138

1.Glycolysis

oOccurs in cytosol

oDoes not require oxygen

2.Intermediate stage

3.Citric acid cycle

4.Electron transport system

**Stages 2, 3, and 4

oOccur in mitochondria

oRequire oxygen

Front 139

Define Glycolysis.

Back 139

Does not require oxygen.

Ten enzymes in cytosol participate.

Glucose broken down into two pyruvate molecules.

Net production of 2 ATP and 2 NADH molecules

Front 140

Steps of Glycolysis.

Glycolysis: Steps 1–5 Glucose split into two molecules of glyceraldehye 3-phosphate (G3P) ATP “invested” at steps 1 and 3 Phosphate groups transferred to break down products of glucose

Glycolysis: Steps 6–7 Occur twice in glucose oxidation Step 6: Unattached Pi added to substrate; two hydrogen atoms released to NAD+ Step 7: Pi transferred to ADP to form ATP

Back 140

Glycolysis: Steps 8–10 Occur twice in glucose oxidationStep 8: molecule from step 7 converted to an isomerStep 9: loss of water moleculeStep 10: Pi transferred to form ATP

Front 141

What are the regulations of glycolysis?

Back 141

Through negative feedback

ATP acting as allosteric inhibitor to “turn off” phosphofructokinase (PFK)

As ATP increases, PFK inhibited

Glycolytic pathway progressively shut down

As ATP decreases, glycolysis increased

Glycolysis decreased by NADH, citrate, fatty acids, and other fuel molecules

Front 142

What is the final product of glycolysis?

Back 142

Pyruvate.

Front 143

What is the overall chemical reaction for glucose oxidation?

Back 143

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Front 144

What are the four stages of cellular respiration for glucose oxidation, and where does each occur?

Back 144

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Front 145

What are the final net products of glycolysis?

Back 145

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Front 146

What are the final net products the intermediate stage from one molecule of glucose?

Back 146

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Front 147

What energy molecules are produced in breaking down one molecule of glucose in the citric acid cycle?

Back 147

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Front 148

What are the three primary steps that take place in the electron transport system?

Back 148

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Front 149

How many ATP are formed from a NADH molecule during oxidative phosphorylation? A FADH2 molecule?

Back 149

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Front 150

Pyruvate is converted to what molecule if there is insufficient oxygen? Why is this done?

Back 150

**

Front 151

Why is oxygen required to burn fatty acids?

Back 151

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