025b metabolism

7/27/2019 025b Metabolism

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The sum total of the chemical processesthat occur in living organisms, resulting

in growth, production of energy,

elimination of waste material, etc.

Anabolism- build up of complex

molecules

Catabolism- break down of complex

molecules

Metabolism


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Fates of

Organic

BuildingBlocks in

ATP

Metabolism

ORGANIC BUILDING BLOCK MOLECULES

Monosaccharides

Amino acids

Acetates

Nucleotide bases

Polymers

&

other

energy

rich

molecules

CO2&

H2O

anabolic

processes

catabolic

processes

ATP

ADP+Pi

energyenergy


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Cellular Respiration

C6H12O6 + 6O2 + 36ADP + 36Pi

6CO2 + 6H2O + 36ATP


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Basic Steps Involved

Glycolysis

Krebs Cycle

Electron Transport System

Acetyl CoA Formation

1

2

3

4


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Overview of

Glycolysis


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Other

Metabolic

Pathways

Fats Glycogen Protein


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GlycolysisC C C C C C

C CC C C

C C C

Net:

2 ATP

2 NADH

2 Pyruvate molecules

4 ATP

2 ATP

Glucose

2 PGAL

2 ADP

4 ADP

2 Pyruvate

2 NAD+

2 NADH

P

C

P


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Balance Sheet for

GlycolysisInput

1 Glucose2 ADP + Pi

2 NAD+

Output2 Pyruvate

2 ATP

2 NADH


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Transition Reaction


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Krebs Cycle

(Citric Acid

Cycle)

Transition

Reaction


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Krebs Cycle (Citric Acid Cycle)


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Balance Sheet for the

Transition Reaction and Krebs

Cycle

Input

2 Pyruvate2 ADP + 2 Pi

8 NAD+

2 FAD

Output

6 CO22 ATP

8 NADH

2 FADH2


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Krebs Cycle

Handles other substrates

Intermediate molecules used:

proteins and lipids

Replenishment of

intermediates necessary

Hans Krebs (1937): paper originally rejected


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Krebs Cycle

Takes 2 completecycles

8 steps, each with

an enzyme


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Krebs Cycle 3


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Oxidative Phosphorylation

ChemiosmosisElectrons are transferred from complex to complex and

some of their energy is used to pump protons (H+) into the

intermembrane space, creating a proton gradient.

ATP synthesis is powered by the

flow of H+ back across the innermitochondrial membrane through

ATP synthase.


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Each Glucose Molecule

CO2 6

NADH 10

FADH2 2

ATP 4


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CO2 6

NADH 10

FADH2 2

ATP 4

used to make ATP


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Electron Transport System 4


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+Pi


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Electron Transport Chain and

Oxidative Phosphorylation Electrons are delivered to O, forming O

O attracts H+ to form H2O


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Figure 24.9

Glycolysis Krebs

cycle

Electron trans-

port chain

and oxidative

phosphorylation

Enzyme

Complex I

Enzyme

Complex III

Enzyme

Complex IV

Enzyme

Complex II

NADH+H+

FADH2

FeegreavtoOk

mo


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Electronic Energy Gradient

Transfer of energy from NADH + H+ and

FADH2 to oxygen releases large

amounts of energy This energy is released in a stepwise

manner through the electron transport

chain


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ATP Synthase

Two major parts connected by a rod

1. Rotor in the inner mitochondrial

membrane2. Knob in the matrix

Works like an ion pump in reverse


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Figure 24.11

Mitochond r ia l matr ix

In termembrane space

ADP

+

A stator anchored inthe membrane holdsthe knob stationary.

As the rotor spins, arod connecting thecylindrical rotor andknob also spins.

The protruding,stationary knobcontains threecatalytic sites that

join inorganicphosphate to ADPto make ATP whenthe rod is spinning.

A rotor in themembrane spins

clockwise when H+flows through it downthe H+ gradient.


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Net ATP Yield

34 to 36 molecules ATP for every

glucose molecule

about 40% efficiency

ATP


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Transition cycle


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Overall ATP

ProductionElectron Transport System 34

Citric Acid Cycle 2Glycolysis 2

SUBTOTAL 38

NADH Transport into Mitochondrion*

-2

TOTAL 36


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Fermentation(Anaerobic Respiration)

L ti A id


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Lactic Acid

Fermentation

C

Glucose 2 Pyruvate 2 Lactic Acid

NAD+

NADH

NAD+

NADH

(Glycolysis) (Lactic acid fermentation)C C C C C C C C C C C


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Glucose

Pyruvate

Acetyl CoA

Ethanolor

LactateKrebs

Cycle

AnaerobicRespiration

AerobicRespiration
http://www.mitochondria.us/index.html


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INQUIRY

1. What is the end product in glycolysis?

2. What substance is produced by theoxidation of pyruvate and feeds intothe citric acid cycle?

3. Name a product of fermentation.

4. What role does O2 play in aerobic

respiration?5. What stage during cellular respiration is the

most ATP synthesized?

6. What is chemiosmosis?

7. When NAD+ and FAD+ are reduced whatdo they form?

8. What are they used for?
http://www.mitochondria.us/index.html

025b metabolism

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