Ch 7 Cellular Respiration

Front 1

Why do organic compounds possess potential energy?

Back 1

As a result of the arrangement of electrons in the bonds between their atoms

Front 2

Fermentation

Back 2

CATABOLIC PROCESS

-makes a limited amount of ATP from glucose...

-without an ETC

-produces an end product (like alcohol or lactic acid)

Front 3

What is the most efficient catabolic pathway?

Back 3

Aerobic respiration

Front 4

Cellular respiration

Back 4

Catabolic pathways of aerobic & anaerobic respiration

-break down organic molecules & use an ETC for production of ATP

Front 5

Aerobic respiration equation

Back 5

organic compounds + O2

------------> CO2 + water + energy

Front 6

Cellular respiration equation

Back 6

C6H12O6 + 6O2 --> 6CO2 + 6H2O + ATP/ENERGY

Front 7

Is cellular respiration exergonic or endergonic?

Back 7

EXERGONIC

Front 8

What is the free-energy change of cellular respiration?

Back 8

-686 kcal per mol of glucose decomposed

(♢G = -686 kcal/mol)

Front 9

What does a negative ♢G mean?

Back 9

The products of the chemical process store less energy than the reactants

The reaction can happen spontaneously (w/o an input of free energy)

Front 10

How do catabolic pathways (that decompose glucose & other organic fuels) produce energy?

Back 10

The relocation of electrons releases energy stored in organic molecules

-this energy ultimately is used to synthesize ATP

Front 11

Redox reactions

Back 11

Chemical reaction involving the transfer of 1+ electrons from one reactant to another

{short for reduction - oxidation reaction}

Front 12

Oxidation

Back 12

The loss of electrons or protons from a substance

Front 13

Reduction

Back 13

Addition of electrons or protons to a substance

Front 14

Reducing agent

Back 14

The electron/proton donors

(Xe-)

Front 15

Oxidizing agent

Back 15

Electron acceptor

(Y)

Front 16

What is oxidized in cellular respiration?

Back 16

C6H12O6 becomes oxidized

(to 6CO2)

Front 17

What is reduced in cellular respiration?

Back 17

6O2 is reduced

(to 6H2O)

Front 18

In respiration, the oxidation of glucose transfers _________ to a lower energy state. This liberates energy that becomes available for ATP synthesis.

Back 18

Electrons

Front 19

NAD+

Back 19

Coenzyme & electron carrier

Front 20

Why is NAD+ well suited as an electron carrier?

Back 20

Because it can cycle easily b/n oxidized NAD+ and reduced NADH states

Front 21

As an electron {acceptor/donor}, NAD+ functions as an oxidizing agent during respiration.

Back 21

ACCEPTOR

Front 22

How does NAD+ trap electrons from glucose & other organic molecules?

Back 22

Dehydrogenases (enzymes) remove a pair of hydrogen atoms (2 electrons & 2 protons) from the substrate (glucose in this case)...

-Thereby oxidizing it.

-the enzyme delivers the 2 electrons & 1 proton to its coenzyme, NAD+

Front 23

What causes NAD+ have its charge neutralized when reduced to NADH?

Back 23

NAD+ recieves 2 e- and 1 H+

Front 24

What does each NADH molecule formed during respiration represent?

Back 24

Stored energy that can be tapped to make ATP when the electrons complete their "fall" down an energy gradient from NADH to O2

Front 25

How do electrons that are extracted from glucose (and stored as potential energy in NADH) finally reach oxygen?

Back 25

Cellular respiration brings hydrogen & oxygen together to form water

Front 26

Electron transport chain (ETC)

Back 26

Sequence of electron carrier molecules (membrane proteins)

-shuffle electrons down a series of redox reactions that release energy used to make ATP

Front 27

Where are ETCs located?

Back 27

Inner membrane of the mitochondria

Front 28

{In the ETC...} electrons removed from glucose are shuttled by ______ to the "top," higher-energy end of the chain.

Back 28

NADH

Front 29

{In the ETC...} at the "bottom," lower-energy end, ______ captures the electrons forming water

Back 29

O2

Front 30

Electron transfer from NADH to O2 is an {exergonic/endergonic} reaction.

Back 30

Exergonic

Front 31

How is energy released efficiently when electrons are sent down the ETC?

Back 31

Electrons cascade down the ETC from one carrier molecule tonthe next...

-losing a small amount of energy with each step

-until they finally reach oxygen

Front 32

The electrons transfered from glucose to NAD+ fall down an _________ in the ETC to a more stable location in the electronegative oxygen atom.

Back 32

Energy gradient

Front 33

During cellular respiration, electrons travel this "downhill" route...

Back 33

Glucose ---> NADH ---> ETC ---> oxygen

Front 34

3 stages of cellular respiration

Back 34

1. Glycolysis

2. Krebs cycle

3. Oxidative phosphorylation

Front 35

Glycolysis

Back 35

A series of reactions that ultimately splits glucose into pyruvate

Front 36

Where does glycolysis occur?

Back 36

Cytosol

Front 37

Glycolysis begins by breaking glucose into ____________.

Back 37

2 molecules of pyruvate

Front 38

Once created, pyruvate enters the mitochondria and is oxidized to a compound called....

Back 38

Acetyl coA

Front 39

Once pyruvate is oxidized to Acetyl coA, it enters the...

Back 39

KREBS CYCLE

Front 40

In the krebs cycle, the breakdown of ______ to ______ is completed.

Back 40

Glucose to carbon dioxide

Front 41

The energy released at each step of the ETC is stored in a form the mitochondria can use to make ______ from ______.

Back 41

ATP from ADP

Front 42

Oxidative phosphorylation

Back 42

Production of ATP using energy derived from the redox reactions of an ETC

Front 43

Substrate level phosphorylation

Back 43

ATP SYNTHESIS

occurs when an enzyme transfers a phosphate group from a substrate molecule to ADP

Front 44

For each molecule of glucose degraded to CO2 and water by respiration, the cell makes up to about ___ molecules of ATP.

Back 44

32

Front 45

What does the word "glycolysis" mean?

Back 45

"Sugar splitting"

Front 46

In glycolysis, glucose (6 carbon molecule) is split into ______, which are then oxidized. Remaining atoms are rearranged to form _______.

Back 46

2 (3-carbon) sugars;

2 molecules of pyruvate

Front 47

What is the net energy yield from glycolysis?

Back 47

2 ATP

&

2 NADH

Front 48

Is any CO2 released during glycolysis?

Back 48

NO

all the carbon originally present in glucose is accounted for in the 2 molecules of pyruvate

Front 49

Glycolysis occurs whether or not ____ is present.

Back 49

O2

Front 50

If O2 is present, the chemical energy stored in pyruvate & NADH can be extracted by ______, ______, & ______.

Back 50

Pyruvate oxidation,

Citric acid cycle,

Oxidative phosphorylation

Front 51

How much chemical energy does glycolysis release?

Back 51

Less than 25% of chem. energy in glucose that can be harvested by cells

(Most of the energy stays in the 2 pyruvates)

Front 52

If O2 is present, the pyruvate enters a mitochondria, where the ______ of glucose is completed.

Back 52

Oxidation

Front 53

Once inside the mitochondria, pyruvate undergoes a series of enzymatic reactions that do what?

Back 53

Remove CO2,

oxidizes the remaining fragment- forming NADH from NAD+

Front 54

The citric acid cycle generates __ ATP per turn by substrate level phosphorylation.

Back 54

1

Front 55

Where does most of the chemical energy from the citric acid cycle go?

Back 55

Transferred to NAD+ & FAD.

NADH & FADH2 shuttle their cargo of high energy electrons to the ETC

Front 56

For each turn of the krebs cycle, __ carbons enter an acetyl group. __ different carbons leave in CO2 molecules.

Back 56

2;

2

Front 57

What forms citrate?

Back 57

The acetyl group of acetyl coA combines with oxaloacetate ( OAA )

( step 1 )

Front 58

What are the last 7 steps of the citric acid cycle doing?

Back 58

Decompose the citrate back to oxaloacetate

Front 59

For each acetyl group entering the citric acid cycle, ___ NAD+ are reduced to NADH (steps 3, 4, and 8)

Back 59

3

Front 60

In step 6, electrons are transferred to FAD, which accepts __ electrons & __ protons to become FADH2.

Back 60

2;

2

Front 61

In step 5, what produces a GTP molecule?

Back 61

Substrate level phosphorylation

Front 62

What does GTP do?

Back 62

Either used to make an ATP molecule

or

directly power work in the cell

Front 63

Is ATP generated during the citric acid cycle?

Back 63

Yes, ONCE.

step 5

Front 64

Most of the ATP produced by respiration is from...

Back 64

Oxidative phosphorylation...

when NADH & FADH2 {produced by the citric acid cycle} relay the electrons extracted from food to the ETC.

Front 65

How many ATPs are produced from glycolysis & citric acid cycle?

Back 65

Each 2 atp per glucose molecule

(By substrate level phosphorylation)

Front 66

Why is it good that the ETCs are in the cristae?

Back 66

Folds of the cristae make bigger surface area... thousands of ETC can go there

Front 67

During electron transport, electron carriers alternate between... And... States

Back 67

Reduced ; oxidized

As they accept and donate electrons

Front 68

Is the upper part of the ATC less electronegative then the bottom part?

Back 68

Yes

Front 69

Electrons removed from glucose by NAD+ during glycolysis & the citric acid cycle are transferred from NADH to the first molecule of the electron transport chain in...

Back 69

Complex 1

Front 70

Ubiquinone

Back 70

Small hydrophobic molecules that is mobile with in the membrane rather than residing in a particular complex

Front 71

Cytochromes

Back 71

A protein that is a component of electron transport chains

Front 72

What part of cytochrome accept and donate electrons?

Back 72

Their prosthetic group (heme group) has an iron atom that accept and donates electrons

Front 73

Fadh2 adds its electrons to the electron transport chain from within... At a lower energy level than NADH does

Back 73

COMPLEX II

Front 74

Does the electron transport chain provide less energy for ATP synthesis when the electron donor is fadh2 rather than NADH?

Back 74

Yes!

Front 75

Does the ETC make ATP directly?

Back 75

No!

It eases the fall of electrons from food to oxygen, breaking a big free-energy drop into a series of smaller steps that release energy and manageable amounts

Front 76

ATP synthase

Back 76

Membrane protein complex

Functions in chemiosmosis with adjacent electron transport chains using energy from a proton concentration gradient to make ATP

Front 77

Chemiosmosis

Back 77

Energy coupling mechanism that uses energy stored as a hydrogen ion gradient to drive cellular work such as the synthesis of ATP

Front 78

Proton motive force

Back 78

Potential energy stored as a proton electrochemical gradient generated by the pumping of hydrogen ions across a membrane during chemiosmosis

Front 79

Alcoholic fermentation

Back 79

Glycolysis followed by the reduction of pyruvate to ethyl alcohol.

Regenerating NAD+ and releasing CO2

Front 80

Lactic acid fermentation

Back 80

Glycolysis followed by the reduction of pyruvate to lactate.

Regenerating NAD+ with no release of CO2