Respiration

How Is a Marathoner Different from a Sprinter?

Aerobic vs. anaerobic

Aerobic vs. Anaerobic

Aerobic pathways

• Newer• Require O• Start in cytoplasm• Completed in

mitochondria

Anaerobic pathways

• Older• No O• In cytoplasm

Food Sources

• Autotrophs (producers)

• Hetrotrophs (consumers)

• Both make ATP

CO2

H2O

Glucose

O2

ATP

ECOSYSTEM

Sunlight energy

Photosynthesis in chloroplasts

Cellular respiration in mitochondria

(for cellular work)

Heat energy

Energy Consumption

Why Breathe?

CO2

CO2

O2

O2Bloodstream

Muscle cells carrying out

Cellular Respiration

Breathing

Glucose O2

CO2 H2O ATP

Lungs

Summary Equation for Aerobic Respiration

C6H12O6CO26 H2O ATPs

Glucose Oxygen gas Carbon dioxide

6

Water Energy

O2 6+ + +

Electron Transfers

• Oxidation - lose electron

• Reduction - gain electron

C6H12O6 6 O2 6 CO2 6 H2O

Loss of hydrogen atoms (oxidation)

Gain of hydrogen atoms (reduction)

Energy

(ATP)Glucose

+ + +

Coenzymes

• NAD+ and FAD

• NADH and FADH2

• Carry electrons and hydrogen

Coenzymes

OH H O 2H

Reduction

Dehydrogenase

(carries2 electrons)

NAD 2H

2H 2e

NADH H

Oxidation

+

+

+

+

ETC

H2O

NAD

NADH

ATP

H

H

Controlled release of energy for

synthesis of ATP

Electron transport chain

2 O2

2e

2e

1

2

NADH

NADH FADH2

GLYCOLYSIS

Glucose Pyruvate CITRIC ACID CYCLE

OXIDATIVE PHOSPHORYLATION

(Electron Transport and Chemiosmosis)

Substrate-level phosphorylation

Oxidative phosphorylation

Mitochondrion

and

High-energy electrons

carried by NADH

ATPATPATP

CO2 CO2

Cytoplasm

Substrate-level phosphorylation

Figure 6.6

Overview

• C6H12O6

Glucose

In-text figurePage 136

Glycolysis

Glycolysis

• Two stages

• Energy-requiring steps

– 2 ATP

– Transfers P group

• Energy-releasing steps

– Splits activated glucose

– Forms 2 pyruvate, 4 ATP and 2 NADH

Glycolysis

NAD NADH H

Glucose2 Pyruvate

ATP2P2 ADP

22

2

2

+

+

Figure 6.8_1

Figure 6.8_2

Figure 6.8_3

“Prep” Reaction

Pyruvate is oxidized • 2 C acetyl-CoA

• 3rd C released as CO2

• NAD+ -> NADH

“Prep” Reaction

CO2

Pyruvate

NAD NADH H

CoA

Acetyl CoA(acetyl coenzyme A)

Coenzyme A

Figure 6.8

Citric Acid Cycle

CoACoA

CO2

NAD

NADHFAD

FADH2

ATP P

CITRIC ACID CYCLE

ADP

3

3

3 H

Acetyl CoA

2

Citric Acid Cycle

• Loads e- and H onto NAD+ and FAD

• ATP by substrate-level Phos.

•1 turn yields:– 2 CO2

– 1 ATP,

– 3 NADH

– 1 FADH2

– Regenerates starting product

Citric Acid Cycle

and Steps and

CITRIC ACID CYCLE

Oxaloacetate

CoA

CoA

2 carbons enter cycle

Acetyl CoA

Citrate

leaves cycle

H

NAD

NADH

CO2

Alpha-ketoglutarate

leaves cycleCO2

ADP P

NAD

NADH H

ATP

Succinate

FAD

FADH2

Malate

H

NAD

NADH

Step

Acetyl CoA stokes the furnace.

Steps

NADH, ATP, and CO2 are generated during redox reactions.

Redox reactions generate FADH2 and NADH.

Electron Transport

• Coenzymes deliver electrons• Pump H+ • Forms H+ gradient• H+ flows down gradient• Powers ATP formation (ATP

synthase)

Figure 6.12a

Importance of Oxygen

Intermembrane space

Inner mitochondrial membrane

Mitochondrial matrix

Protein complex

Electron flow

Electron carrier

NADH NAD+

FADH2 FAD

H2OATPADP

ATP synthase

H+ H+ H+

H+

H+H+

H+

H+

H+

H+

H+

H+

H+

H+

P

O2

Electron Transport Chain Chemiosmosis

.

OXIDATIVE PHOSPHORYLATION

+ 212

Figure 6.10

Summary of Energy Harvest

(per molecule of glucose)• Glycolysis

– 2 ATP

• Citric acid and “prep” rxns– 2 ATP

• ETC

– 32 ATP formed

• 686 kcal of energy are released

• 7.5 kcal are conserved in each ATP

• When 36 ATP form, 270 kcal (36 X 7.5) are

captured in ATP

• Efficiency is 270 / 686 X 100 = 39 percent

• Most energy is lost as heat

FYI - Efficiency of Aerobic Respiration

Poisons•Block the movement of electrons (cyanide, CO)

•Block the flow of H+ through ATP synthase (Oligomycin)

H+

H+

H+

H+

H+

H+ H+ H+ H+

H+

H+

H+H+

O2

H2OP ATP

NADH NAD+

FADH2 FAD

Rotenone Cyanide, carbon monoxide

Oligomycin

DNP

ATPSynthase

2

ADP

Electron Transport Chain Chemiosmosis

12

Figure 6.11

Anaerobic Pathways

• Less ATP

• Fermentation pathways

Fermentation Pathways

• Bacteria – Lactobacillus (cheese)

• Animal cells

Fermentation Pathways

• Glycolysis

• 2 ATP

• Regenerate NAD+

Lactate Fermentation

• Muscle cells FAST ATP • Lactic acid builds up

2 Lactate

NAD NADH NADH NAD2 2 22

2 ATP2 ADP 22 Pyruvate

GLYCOLYSIS

P

Glucose

Alcoholic Fermentation• Produces ethanol• Yeast

NAD NADH NADH NAD2 2 2 2

GLYCOLYSIS

2 ADP 2 P ATP

Glucose 2 Pyruvate

releasedCO2

2 Ethanol

22

Figure 6.13B

Figure 6.16

Question of the Day

How does the insecticide rotenone work? Is it safe?