Chapter 09 AP

8/3/2019 Chapter 09 AP

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Chapter 9: Cellular Respiration


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Word Roots:

cata- = down

an- = up

bio- = life

kinet- = movement

therm- = heat

ex- = out

endo- = within

allo- = different Bioenergetics the study of howorganisms manage their energy

resources.

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Energy

Transfer

In Life


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Reaction Coupling

Catabolic reactions

Fermentation

Cellular Respiration

Anabolic reactions

Macromolecules

ATP

Glucose (C6H12O6) G = - 686 kcal/mol

ADP + Pi + 7.3 kcal/mol ATP

C6H12O6 + 6 O2 6 CO2 + 6 H2O + Energy (ATP + heat)


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Oxidation/Reduction Reactions (Redox)

The relocation of e- releases E from organic molecules.

Loss of is e- oxidation.

Gain of is e- reduction.

LEO the lion goes GER!!!


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e- donor reducing agent.

e-

acceptor oxidizing agent.Note: Redox can happen without a complete transfer of electrons.

Highly electronegative atoms are strong oxidizers Oxygen.


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Pulling e- away from an atom requires energy

e- lose energy when then move from a less electronegative atom to a

more electronegative atom.

e-

O2


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Hydrogen low electronegativity

Oxygen high electronegativity

Hydrocarbons many uphill e-

Gasoline

Glucose

Excellent fuel source lots of e- to travel downhill energy

released.

H

O

e-

www.tva.gov


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Energy Release


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Glucose is broken down in steps.

Electrons are removed transported with protons

Carried by NAD+ - nicotinamide adenine dinucleotide

Niacin

Dehydrogenase

Reduced

Oxidized


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e- transfer to O2 from NADH G = - 53 kcal/mol

FOOD

OXYGEN

ETC

NADH


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The Stages of Cellular Respiration: A Preview


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The Stages of Cellular

Respiration: A Preview

Stage-1: Glycolysis

No O2

Cytoplasm

Substrate LevelPhosphorylation

Catabolic

Dehydrogenases and

NAD+


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Stage-2: Citric Acid Cycle

O2

Mitochondrial Matrix

Substrate Level Phosphorylation

Catabolic

Dehydrogenases and NAD+

Stage-3: Electron Transport Chain

O2

Mitochondrial Inner MembraneOxidative Phosphorylation

Anabolic

Proton Pump and ATP synthase


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Glycolysis

Hexose to Triose

Glucose Oxidized toPyruvate

Energy Investment

Phase

Energy Payoff Phase


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Energy Investment Phase

Step 1:

Hexokinase

Phosphate traps glucose

Increases reactivity


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Step 2:

Isomerases


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Step 3:

Activated for cleavage

Allosterically regulated


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Step 4:

Cleavage

Creation of StructuralIsomers

Step 5:

Isomerase

Active molecule G-3-P


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Energy Payoff Phase

Step 6:

Sugar is oxidized

Very exergonic

Phosphorylation of oxidized sugar


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Step 7:

Substrate Level

phosphorylation

Sugar oxidized to and organic

acid


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Step 8:

Phosphate relocated


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Step 9:

Dehydration reaction

Creation of double bondPhosphate bond unstable


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Step 10:

Substrate level

phosphorylation

Net 2 ATP produced.


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Glycolysis a

review

ATP usedATP produced

NADH produced


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The Glycolysis/Citric Acid Intermediate

O2 Required

Mitochondrial Matrix

Active transport of pyruvate

Creation of Acetyl Coenzyme A

Fully

oxidized

very

little E 2-C molecule

Sulfur-containing

Very

Reactive


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The Citric Acid Cycle

Tricarboxylic Acid Cycle

Krebs Cycle Hans Krebs 1930s

8 Steps

Specific enzymes

Cycle 2 times per glucose

FAD flavin adenine dinucleotide

riboflavin


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Step 1:

2-C + 4-C = 6-C

Coenzyme A recycled

Step 2:

Isomerase


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Step 3:

CO2 released

NAD+ NADH

Step 4:

CO2 released

NAD+ NADH

Coenzyme A added


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Step 5:

Coenzyme A removed

GDP GTP

Substrate-level

phosphorylation ATP!

Step 6:

FAD FADH2


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Step 7:

Hydration reaction

Bond rearrangement

Step 8:

OAA regenerated

NAD+ NADH


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The Citric Acid Cycle A Review

CO2

Per glucose: 4

Per pyruvate: 2

NADH

Per glucose: 6

Per pyruvate: 3

FADH2

Per glucose: 2

Per pyruvate: 1

ATP

Per glucose: 2

Per pyruvate: 1


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Pathway of the Electron Transport Chain

Inner membrane of the mitochondria

Cristae

4 protein components I- IV

Prosthetic groups

e- carriers arranged in a downhill formation

NADH begins at Protein Complex I

FADH2 begins at Protein Complex II


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Protein Complex I

Flavoprotein

Flavin mononucleotide

Iron-sulfide

Ubiquinone

Non-proteinHydrophobic

Mobile

Protein Complex II

FAD

Iron-sulfide


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Protein Complex III

Cytochrome b (heme)

Iron-sulfideCytochrome c1 (heme)

Cytochrome c

Not in a protein

Protein Complex IV

Cytochrome a (heme)

Cytochrome a3 (heme)

Oxygen

Final electron acceptor


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The Electron Transport Chain

Makes no ATP directly

G = -53 kcal/mol

Proton gradient created


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Chemiosmosis Energy coupling

Inner mitochondrial memebrane

ATP synthase

Reverse ion pump

Proton-motive force

Bacteria

Gradient across cell

membrane

Generate ATP

Pump materials

Rotate flagella


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Accounting 101

NADH = Max 3 ATP

10 H+ across membrane

3-4 H+ = 1ATP

FADH2 = max 2 ATP

Shuttle from Cytoplasm

NAD+ - liver cells

FAD brain cells

Total 36-38 ATP produced

40% efficient


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Fermentation

No O2 anaerobic

Substrate-level phosphorylation

NAD+


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Alcoholic Fermentation

Yeast

Bacteria

Lactic Acid Fermentation

Bacteria

Fungi

Muscle cells

Liver recycles lactic acid

Facultative Anaerobes


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Evolutionary Significance

O2 lacking in primitive atmosphere

Heterotroph Hypothesis

Anaerobic Heterotrophs Anaerobic Autotrophs Aerobic

Heterotrophs Aerobic Autotrophs


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Metabolic Pathways -

Catabolism

Proteins

Deamination

Fats

Gycerol G-3-P

Beta oxidation


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Metabolic Pathways Anabolism

Biosynthesis

Create amino acids

Acetyl CoA fatty acids

Dihydroxacetone Phosphate fat

precursor


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Chapter 09 AP