Chapter 9

Front 1

Energy flows into an ecosystems as

Back 1

sunlight and leaves as heat

Front 2

Photosynthesis generates O2 and organic molecules

Back 2

which are used in cellular

Front 3

cells use chemical energy stored in organic molecules

Back 3

to regenerate ATP, which powers work

Front 4

______ consumes organic molecules and O2 and yields ATP

Back 4

Aerobic respiration

Front 5

______ is a partial degradation of sugars that occurs wihtout O2

Back 5

Fermentation

Front 6

Anaerobic respiration is similar to aerobic respiration but ________

Back 6

consume compounds (sulfate as in sulfur bacteria) other than O2

Front 7

_____ includes both aerobic and anaerobic respiration but is often used to refer to aerobic respiration

Back 7

Cellular respiration

C6H12O6+6(O2)->6(CO2)+energy(ATP+heat)

Front 8

The transfer/relocation of electrons during chemical reactions _______

Back 8

releases energy stored in organic molecules

-ultimately used to synthesize ATP

Front 9

Chemical reaction that transfer electrons between reactants are called

Back 9

oxidation-reduction reaction or redox reactions

Front 10

a substance loses electrons or is oxidized

Back 10

Oxidation

Front 11

a substance gains electrons, or is reduced (amount of positive charge is reduced)

Back 11

reduction

Front 12

The electron donor is called the

Back 12

reducing agent

Front 13

The electron receptor is called the

Back 13

Oxidizing agent

Front 14

Some redox reductions reactions do not transfer electrons but

Back 14

change the electron sharing in covalent bonds

-causes release of energy due to change in electron position

Front 15

Change in position means change in ______ of the electron which causes _______

Back 15

potential energy;release of energy

Front 16

high electronegative atom attract electron more towards itself thus

Back 16

causing changes in position of electron and consequent release of energy

Front 17

During cellular respiration the fuel (glucose) is

Back 17

oxidized and O2 is reduced

-indicates that hydrogen is transferred from glucose to oxygen molecule but what is invisible is change in position of electrons as O attract electrons towards itself

Front 18

Organic molecules that have an abundance of hydrogen are

Back 18

excellent fuels

Front 19

In cellular respiration, glucose and other organic molecules are broken down in a series of steps;

Back 19

electron travel with a proton thus as a hydrogen atom

Front 20

Electrons from organic compounds are usually first

Back 20

transferred to an electron carrier NAD+, coenzyme, a derivative of vitamin niacin

Front 21

As electron acceptor, NAD+ functions as an

Back 21

oxidizing agent during cellular respiration

Front 22

Each NADH(the reduced form of NAD+) represents

Back 22

stored energy that is tapped to synthesize ATP

Front 23

NAD+ can accept 2 electron and 1 H+(proton) and release

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H+(proton) in the medium

Front 24

Electrons loose very little of their potential energy when they

Back 24

transferred from glucose to NAD+

Front 25

NADH passes the electrons to the electron transport chain Unlike an uncotrolled reaction, the electron transport chain passes electrons in a

Back 25

series of steps of one explosive reaction

Front 26

Harvesting of energy from glucose has three stages:

Back 26

-Glycosis

-Citric acid cycle

-Oxidative phosphorylation

Front 27

Glycosis

Back 27

Breaks down glucose into two molecules of pyruvate (in the cytoplasm)

Front 28

Citric acid cycle

Back 28

completes the breakdown of glucose (in the mitochindrial matrix)

Front 29

Oxidative phosphorylation

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accounts for most of the ATP synthesis (inner mitochondrial membrane (26/28 glucose molecule) generated by cellular respiration

Front 30

A smaller amount of ATp is formed in

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Glycosis(2ATP/Glucose) and in the citric acid cycle (2ATP/Glucose) by substrate-level phosphorylation

Front 31

Transfer of Phosphate groupnot inorganic phosphate (Pi)

Back 31

which only takes place during oxidative phosphorylation (ADP+iP=ATP)

Front 32

Glycosis has two major phases

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-Energy investment phase

-Energy payoff phase

(Glycosis occurs whether or not O2 is present)

Front 33

Oxidation of pyruvate to Acetyl CoA

Back 33

-Before the citric acid cycle can begin, pyruvate must be convertedto acetyl Coenzyme A (acetyl CoA), which links glycosis to the citric acid cycle

Front 34

Oxidation of pyruvate to Acetyl CoA STEPS

Back 34

This step is carried out by multienzyme complex that catalyses three reactions:

-I Removal of CO2

-II Conversion of NAD+ to NADH

-III Addition of CoA-SH(derived from Vitamin B

Front 35

Glucose produces ____ molecules of Pyruvate

Back 35

2

Front 36

The citric acid cycle or TCA cycle, also called _______ completes the break down of pyruvate to CO2

Back 36

Krebs cycle

Front 37

Pyruvate is 3 Carbon containing compound:

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1 CO2 molecule release at PDH step and 2 CO2 release in TCA cycle

Front 38

The cycle oxidizes organic fuel derived from pyruvate generating

Back 38

1ATP, 3NADH, and 1FADH2 per turn

Front 39

The TCA cycle has 8 steps each catalyzed by a specific enzyme

Back 39

The acetyl group of acetyl CoA joins ther cycle by combining with oxaloacetate, forming citrate

Front 40

Next seven steps decompose the citrate back to

Back 40

Oxaloacetate, making the process a cycle

Front 41

The NADH and FADH2 produced by the cycle relay electrons extracted from

Back 41

food to the electron transport chain

Front 42

Following glycosis and the citric acid cycle, ________ and ______ account for most of the energy extracted from food

Back 42

NADH and FADH2

Front 43

These two electron carriers donate electrons to the electron transport chain which

Back 43

powers ATP synthesis via oxidative phosphorylation

Front 44

The electron transport chain is in the

Back 44

inner membrane (cristae) of the mitochondria

Front 45

Most of the chain's componenets are proteins which

Back 45

exist in multiprotein complezes

Front 46

The carriers alternate ____ and ____ states as they accept and donate electrons

Back 46

reduced and oxidized

Front 47

Electrons drop in free energy as they go

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down the chain and are finally passed to O2 forming H2O

Front 48

Mobile carrier of electron between III and IV

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Cytochrome C

Front 49

Electrons are transferred from NADH or FADH2 to

Back 49

the electron transport chain

Front 50

Electrons are passed trough a number of proteins including

Back 50

cytochromes (each with an iron atom) to O2

Front 51

The electron transport chain generates

Back 51

no ATP directly

Front 52

ETC breaks the large free-energy drop from food to O2 into

Back 52

smaller steps that release energy in manageable amounts

Front 53

Electron transfer in the electron transport chain causes proteins to pump

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H+ from the mitochondrial matrix to the intermembrane space

Front 54

H+ then moves back across the membrane

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passing through the proton pump, ATP synthase

Front 55

ATP synthasse uses the exergonic flow of H+ to

Back 55

drive phosphorylation of ATP

Front 56

The use of energy in a H+ gradient to drive cellular work is an example of

Back 56

chemiosmosis

Front 57

The energy stored in a H+ gradient across a membrane couples

Back 57

the redox reactions of the electron transport chain to ATP synthesis

Front 58

The H+ gradient is referred to as a

Back 58

proton-motive force, emphasizing its capacity to do work

Front 59

During cellular respiration, most energy flows in this sequence:

Back 59

Glucose->NADH->electron transport chain->proton-motive force->ATP

Front 60

About 34% of the energy in glucose molecule is transferred to ATP during cellular respiration,

Back 60

making about 32 ATP (BROWN FAT)

Front 61

Most cellular respiration requires O2 to produce ATP

Back 61

without O2 the electron transport chain will cease to operate

Front 62

In the case electron transport ceases to operate than

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glycosis couples with fermentation or anaerobic respitation to produce ATP

Front 63

Anaerobic respiration uses an electron transport chain with a

Back 63

final electron acceptor other than O2, for example sulfate

Front 64

Fermentation uses ________ instead of an electron transport chain to generate ATP

Back 64

substrate-level phosphorylation

Front 65

Fermentation consists of glycolysis plus reactions that

Back 65

regenerate NAD+, which ccan be reused by glycolysis. Without NAD+ glycolysis will not work thus fermentaton provides NAD+ to the glycolysis by oxidizing NADH

Front 66

Under aerobic conditions TCA cycle recycle

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NAD+ after oxidizing NADH by ETC

Front 67

Two common types of fermentation are

Back 67

alcohol fermentation

lactic acid fermentation

Front 68

In alcohol fermentaion

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pyruvate is converted to ethanol in 2 steps with the first releasing CO2

Front 69

In lactic acid fermentation

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pyruvate is reduced to NADH forming lactate as an end product with no releae of CO2

Front 70

All use glycolysis (net ATP=22) to

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Oxidize glucose and harvest chemical energy of food

Front 71

In all three NAD+ is the

Back 71

oxidizing agent that accpets electrons during glycolysis

Front 72

The processes have different final electron acceptors:

Back 72

an organic molecule (such as pyruvate or acetaldehyde) in fermentation and O2 in cellular respiration

Front 73

_______ carry out fermentation or anaerobic repiration and cannot survive in the presence of O2

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Obligate anaerobes

Front 74

Yeast and many bacteria are _______, meaning that they can survive using either fermentation or cellular respirtaion

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facultative anaerobes

Front 75

In a facultative anaerobe, pyruvate is a

Back 75

fork in the metabolic road that leads to two alternative catabolic routes

Front 76

Ancient prokaryotes are thought to have used glycosis long before

Back 76

there was oxygen in the atmosphere

Front 77

GLycosis occurs in cytoplasm without use of any

Back 77

membrane bound organelle

Front 78

GLycosis and the citric acid cycle are major

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intersections to various catabolic and anabolic pathways

Front 79

_____ is the most common mechanism for control

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Feedback inhibition

Front 80

If ATP concentration begins to drop, respiration speeds up;

Back 80

when there is plenty of ATP, respiration slows down

Front 81

Control of catabolism is based mainly on

Back 81

regulating the activity of enzymes at strategic points in the catabolic pathway