Cellular Respiration (2.8/8.2)


ATP & Cellular Respiration

Cellular Respiration WebQuest

Glycolysis Review:

Krebs Cycle Review:

ETC and Chemiosmosis Review

Cellular Respiration Animation


2.8 Cell respiration

Nature of science:

Assessing the ethics of scientific research—the use of invertebrates in respirometer experiments has ethical implications. (4.5)

Understandings:

Cell respiration is the controlled release of energy from organic compounds to produce ATP.

ATP from cell respiration is immediately available as a source of energy in the cell.

Anaerobic cell respiration gives a small yield of ATP from glucose.

Aerobic cell respiration requires oxygen and gives a large yield of ATP from glucose.

Applications and skills:

Application: Use of anaerobic cell respiration in yeasts to produce ethanol and carbon dioxide in baking.

Application: Lactate production in humans when anaerobic respiration is used to maximize the power of muscle contractions.

Skill: Analysis of results from experiments involving measurement of respiration rates in germinating seeds or invertebrates using a respirometer.

Guidance:

Details of the metabolic pathways of cell respiration are not needed but the substrates and final waste products should be known.

There are many simple respirometers which could be used. Students are expected to know that an alkali is used to absorb CO2, so reductions in volume are due to oxygen use. Temperature should be kept constant to avoid volume changes due to temperature fluctuations.

Aims:

Aim 8: The ethics of the use of animals in experiments could be discussed in relation to respirometer experiments. Large-scale use of food plants for biofuels and the resulting impact on food prices has ethical implications.

Essential idea: Photosynthesis uses the energy in sunlight to produce the chemical energy needed for life.

8.2 Cell respiration

Nature of science:

Paradigm shift—the chemiosmotic theory led to a paradigm shift in the field of bioenergetics. (2.3)

Understandings:

Cell respiration involves the oxidation and reduction of electron carriers.

Phosphorylation of molecules makes them less stable.

In glycolysis, glucose is converted to pyruvate in the cytoplasm.

Glycolysis gives a small net gain of ATP without the use of oxygen.

In aerobic cell respiration pyruvate is decarboxylated and oxidized, and converted into acetyl compound and attached to coenzyme A to form acetyl coenzyme A in the link reaction.

In the Krebs cycle, the oxidation of acetyl groups is coupled to the reduction of hydrogen carriers, liberating carbon dioxide.

Energy released by oxidation reactions is carried to the cristae of the mitochondria by reduced NAD and FAD.

Transfer of electrons between carriers in the electron transport chain in the membrane of the cristae is coupled to proton pumping.

In chemiosmosis protons diffuse through ATP synthase to generate ATP.

Oxygen is needed to bind with the free protons to maintain the hydrogen gradient, resulting in the formation of water.

The structure of the mitochondrion is adapted to the function it performs.

Applications and skills:

Application: Electron tomography used to produce images of active mitochondria.

Skill: Analysis of diagrams of the pathways of aerobic respiration to deduce where decarboxylation and oxidation reactions occur.

Skill: Annotation of a diagram of a mitochondrion to indicate the adaptations to its function.

Guidance:

The names of the intermediate compounds in gylcolysis and the Krebs cycle are not required.

Theory of knowledge:

Peter Mitchell’s chemiosmotic theory encountered years of opposition before it was finally accepted. For what reasons does falsification not always result in an immediate acceptance of new theories or a paradigm shift?

Essential idea: Light energy is converted into chemical energy.

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3.7 RG.pdf
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8.1 RG.pdf
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Jessica Clark,
Jan 13, 2014, 6:53 AM
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Jessica Clark,
Jan 13, 2014, 6:53 AM
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Jessica Clark,
Jan 13, 2014, 6:53 AM
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Jessica Clark,
Jan 13, 2014, 6:54 AM
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