How living organisms harvest and utilize energy

Teachable UnitHow living organisms harvest and utilize energy

Learning Goals:1. Students will be able to define chemical energy, proton gradient,

chemiosmosis, ATP, oxidation and reduction.2. Students will be able to explain the importance of reduction and

oxidation by the electron transport chain in the generation of the proton gradient across the inner mitochondrial membrane.

3. Students will be able to predict what will happen to the rate of ATP synthesis under the following conditions:

- elimination of the proton gradient;- inhibition of electron transport;- diminished oxygen levels.

4. Students will be able to describe the importance of chemiosmosis to the production of ATP.

A Teachable Tidbit #1:Electrons and protons – Pass it on!

Addressing different learning styles in an introductory biology classroom

Learning Goal:

Students will be able to explain the importance of reduction and oxidation by the electron transport chain in the generation of the proton gradient across the inner mitochondrial membrane.

Learning outcomes of Tidbit #1

• Students will be able to illustrate a model of the flow of electrons through the electron transport chain.

• Students will be able to describe the dynamic nature of electron transport and the generation of the proton gradient across the inner mitochondrial membrane.

Prior Learning/Assumptions

Students have already completed readings, lectures, and in discussions:

- Glycolysis- Citric acid cycle- Electron transport- Oxidative phosphorylation

A) pyruvate

B) water

C) NAD+

D) oxygen

1. The final electron acceptor of the electron transport chain that functions in oxidative phosphorylation is:

A) The pH of the matrix increases.

B) The electrons gain free energy.

C) NAD+ is oxidized.

2. When electrons flow down the mitochondrial electron transport chain (ETC) which of the following

occurs?

3. Flow of electrons down the electron transport

chain directly causes:

A) ATP synthesis.B) formation of a proton gradient.C) NADH reduction.D) production of CO2.

A) a decrease in the pH difference across the inner mitochondrial membraneB) increased oxygen consumption andwater productionC) an increased rate of accumulation of NAD+

4. In the presence of a metabolic poison thatspecifically and completely blocks electron flow down the ETC, which would you expect?

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ATP for lifeATP for life

Coupling of ATP synthesis to electron Coupling of ATP synthesis to electron transfertransfer

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are needed to see this picture.

ATP ATP ATP

H+

H+H+

H+

H+

ATPP i

Cyt c

I

IIIII

IV

Electrons fromreduced carbon

NADH+

FADH2

NAD+

FAD+ 2 H+ + 1/2 O2

H2O

ADP +

Electron transport chainElectron transport and pumping of protons (H+)

to establish a transmembrane H+ gradient

ChemiosmosisATP synthesis driven by the flowof H+ back across the membrane

ATPsynthase

Q

Coupling of ATP synthesis to electron Coupling of ATP synthesis to electron transfertransfer

A) pyruvate

B) water

C) NAD+

D) oxygen

1. The final electron acceptor of the electron transport chain that functions in oxidative phosphorylation is:

A) The pH of the matrix increases.

B) The electrons gain free energy.

C) NAD+ is oxidized.

2. When electrons flow down the mitochondrial electron transport chain (ETC) which of the following

occurs?

3. Flow of electrons down the electron transport

chain directly causes:

A) ATP synthesis.B) formation of a proton gradient.C) NADH reduction.D) production of CO2.

A) a decrease in the pH difference across the inner mitochondrial membraneB) increased oxygen consumption andwater productionC) an increased rate of accumulation of NAD+

4. In the presence of a metabolic poison thatspecifically and completely blocks electron flow down the ETC, which would you expect?

Learning Goal:

Students will be able to explain the importance of reduction and oxidation by the electron transport chain in the generation of the proton gradient across the inner mitochondrial membrane.

Diversity considerations:

-Animation with narration addresses visual and audial learners-Activity addresses kinesthetic learners-As many students can be involved as want to be-Assessment of reading and prior learning-Repeated assessment after activity

The focus of this activity was on ETC dynamics. However, this could easily be linked to several human health problems that have been shown to be associated with mitochondrial defects. Examples include Parkinson’s, bipolar disorder, and obesity.

Dinitrophenol (2,4-DNP), a yellow food dye, was once routinely added to commercial baked goods to make them appear "egg rich." In 1933, this manufactured chemical was introduced as a treatment for obesity. DNP helped patients lose weight.

This proved to be very dangerous; many users suffered injury and death due to elevated body temperature. Over one hundred thousand people took these “anti-fat medicines” before they were abandoned in 1937.